1. CMS at LHCD. Adamczyk, D. An⇤, D. Anderson, A. Apresyan, A. Barczyk, A. Bornheim,

M. Bredel, J. Bunn, C. Chang, Y. Chen, S. Cury, G. Denis, F. Dias, E. Di Marco,J. Duarte, C. Flamant⇤, P. Galvez, E. Garza⇤, J. Hardenbrook⇤, M. Horton⇤, S. Hu,

I. Kassymkhanova, D. Kcira, V. Lambert⇤, V. Lapadatescu, H. Lee⇤, L. Lee⇤, I. Legrand,S. Lo, Z. Maxa, R. Mao, A. Mott, A. Mughal, H. Newman, S, Nezami⇤, C. Pena,

M. Pierini, C. Rogan, S. Rozsa, N. Sirohi⇤, M. Spiropulu, K. Swanson⇤, A. Takeda⇤,M. Thomas, T. Tong⇤, J. Trevor, V. Timciuc, G. Upadhya⇤, J. Veverka, J.-R. Vlimant,

R. Voicu, A. Wang⇤, R. Wilkinson, S. Xie, Y. Yang, L. Zhang, K. Zhu, R.Y. Zhu

1.1 Executive Summary

The 2011-13 LHC run marked a centennial milestone: the discovery of a Higgs-like particle ata mass near 126 GeV. As no physics Beyond the Standard Model has yet been found, and themeasured Higgs mass is uncomfortably high for minimal SUSY and uncomfortably small for strongdynamics and vacuum stability, the upcoming LHC Run II at 13 TeV from the Spring of 2015 onwill be crucial in elucidating the emerging picture of TeV scale physics.

Caltech’s rigorous preparatory work and data-driven analyses to accurately understand elec-troweak interactions and QCD have been essential prerequisites for the discovery program. Wediscovered the “breaking” of scaling behaviors such as “Berends-Giele” jet multiplicity scaling,testing higher order QCD e↵ects that have not yet been computed theoretically, and continuedour studies of W+jets and Z+jets, QCD multijet and top+jet events, to provide a more accuratedescription and modeling of SM processes in new physics searches. Throughout LHC Run 1 and inpreparation for Run2, our group has been central in many areas including: 1) design and deploy-ment of the trigger menus for luminosities up to 1034 and beyond, 2) precise ECAL laser monitors(with new solid state blue lasers in 2012) and crystal-by-crystal ⇡0/⌘ calibration, 3) the HCALnoise filters both online and in the prompt o✏ine reconstruction, and 4) optimizing the electron,jets, MET and TeV-muon physics object performance in the presence of increased pileup.

A crucial product of the preparatory work on jets and�ET is Spiropulu and Rogan’s breakthrough

development of the razor kinematic variables and ratios in 2009-11, and ongoing advances togetherwith Duarte since then. This has surpassed the sensitivity of many SUSY searches based on earliermethods, and was recently highlighted at the SUSY2013 and ICHEP 2014 conferences, yielding themost stringent constraints on scalar top quarks. The “razor working group” formed by Spiropuluopened a major new theme in CMS’ searches for SUSY, Higgs, and exotic new physics using thefull 2011-12 dataset, while also probing the regions of SUSY space favored by the 2013 Planckdata and relevant to direct dark matter (DM) searches. The razor is now being applied widely: tothe third generation SUSY sector (signatures with sbottom, stop, or stau); to GMSB SUSY withphotons, jets and

�ET in the final state; and to the Higgs decay channel H ! WW with improved

mass resolution to characterize the signal. It is also used extensively by phenomenologists andtheorists to explore the remaining allowed SUSY and other models’ parameter spaces, combiningall available collider, CMB and other DM-related data. Maurizio Pierini joined the group as avisitor this Spring, strengthening our e↵orts in many areas of razor-based analysis, as well asdeveloping and deploying the physics analysis workflow and data quality monitoring processesCMS-wide as part of the Physics Performance and Dataset (PPD) group. In July 2104 Jean-RochVlimant (previously CERN) joined our group. He has an exceptional record in advanced LHC

⇤Caltech undergraduate

1

1.1 Executive Summary 2

physics software and computing and will engage in advanced machine learning methods in view ofthe massive and complex data and analyses of the upcoming LHC runs.

The Caltech group continues its longstanding leading work on H ! ��,WW and ZZ ! 4lepton studies following the discovery, to rigorously characterize the new particle. This has beena major axis of our work, including new analysis methods, calibration, photon ID, energy scaleand selection optimization in the presence of pileup, as well as the SM background descriptionand understanding. A major direction begun in 2012 by Spiropulu, Chen, Di Marco and Xieand highlighted at the ICHEP 2014 conference is the use of new calculations and computationaltechniques to directly probe the tensor structure of the full SM Lagrangian in ZZ ! 4 leptonevents, to determine the spin and CP of the new particle, building on the ongoing Higgs look-alikework since 2010. Together with the H ! WW work using the razor and the work to lower thelepton thresholds and accurately determine the mass scales in several channels, Caltech’s roles arecentral to CMS’ Higgs searches and ongoing studies of the new boson.

The group’s work in CMS on LHC physics was highlighted at ICHEP 2014, where Di Marcopresented “Studies of the Higgs boson spin and parity using the gamma gamma, ZZ, and WWdecay channels”, Duarte presented “Inclusive SUSY Searches”, and Chen presented “E↵ective HiggsCouplings Extraction in the 4 Lepton Channel” which is the main subject of his thesis.

The Caltech group (Newman, Bornheim, Zhu, Di Marco, Yang and Ma, and students Pena,Veverka,Timciuc and undergraduate Lambert) is one of the strongest (if not the strongest) in theECAL community, with leading roles in ECAL monitoring, trigger, calibration, and defining thereconstructed photon objects, ensuring the best possible overall performance of the ECAL 1.

The Caltech group (Spiropulu, Apresyan, Rogan, Xie and students Chen, Mott and Duarte)has established leading roles in HCAL triggering and operations, extraction and workflow of thecorresponding datasets, and especially jets and

�ET signatures. Spiropulu has been the deputy leader

of the HCAL Detector Performance Group (DPG) and led the Noise Working Group developingthe crucial techniques to suppress the HCAL noise both online and o✏ine. Together with Chen,Apresyan, and Mott they developed an e↵ective filtering suite of algorithms that were an essentialpart of CMS’ online operations, o✏ine reconstruction and analysis which have been adapted andare now commissioned for operations with 25 nsec bunch spacing at LHC Run2. Apresyan, who hasbeen

�ET and JetMET Convenor, is now the DPG Coordinator for HCAL performance overseeing

four HCAL subgroups (DQM/Certification, Noise, CMSSW and Simulation).

We also have established leading roles in R&D for the CMS Upgrade at HL-LHC. Caltechalong with ETH proposed a new radiation-hard crystal scintillator LYSO, which has been studiedin our crystal lab by Zhu et al. over the last decade. The group proposed and now leads thedevelopment of a compact cost e↵ective Shashlik design based on LYSO crystal plates for theupgraded forward ECAL at the high luminosity LHC (HL-LHC), and associated physics studies.The first 4 ⇥ 4 Shashlik test matrix was successfully designed and tested at the Fermilab MTestbeamline this year. As detailed further in Section 1.4 of this report, a new thrust led by Spiropulusince 2012 is the development of picosecond-resolution timing devices at the HL-LHC, to addressthe challenges of high pileup and provide improved vertexing, ID and resolution for photons and jetsin the ECAL, as well as triggering. Recent measurements (August 2014) performed in the FNALtest beam showed that a precision of 15-30 psec has been achieved with the detection of shower

1The ⇡0/⌘ ! �� calibration stream developed by our group, together with Caltech’s laser monitor, has provenindispensable to precisely track radiation-induced transparency changes, and maintain the requisite calibration accu-racy crystal-by-crystal over the ECAL barrel, which is crucial for CMS’ sensitivity to H ! �� and other new physicschannels with photons.

1.2 Physics 3

particles using commercial MCP detectors, and with LYSO crystals measured with MCP-PMTsand digitized with fast electronics

Student Alex Mott headed the online deployment of the trigger menus for the entire CMS triggerin 2011-12. He led the studies and implementation of the SUSY triggers, as well as detector-relatednoise filters with Chen and Apresyan that assure the e�ciency and purity of the SUSY triggers.Chen is convening the HCAL noise group in 2013-14, preparing for the 2015 run.

Caltech group members have been appointed to many important management and coordinationroles in CMS: in physics, triggers, reconstruction, detector operations and development, and thePhase 2 upgrades, and as lead authors on many key papers, as well as founding and ongoing leadroles in software and computing, and networking for the field. Several group members have receivedawards and distinctions both within CMS and worldwide for physics and technology contributionsand advances during the grant period. 3 of the 7 CMS 2011 Student Awards for outstandingwork on the detector went to Mott (global trigger menus and online noise filtering), Yang (ECALcalibration) and Chen (HCAL noise), among all the graduate students from 150 CMS institutions.Orimoto, a former Millikan fellow now on the faculty at Northeastern, received a 2009 CMS Postdocaward for her leadership of the ECAL Prompt Feedback Group (PFG).

We note that historically the group has an exceptional record in launching the careers of itsyoung members. The large majority of our grad students and postdocs as well as many of our un-dergraduates remain in HEP, and many have moved on to faculty positions, including: Chris Tully(Princeton), Giorgio Gratta (Stanford), David Kirkby (Santa Cruz), Aaron Dominguez (Nebraska),Toyoko Orimoto (Northeastern) and Martin Gruenewald (Ghent), as well as senior sta↵ memberssuch as Hong Ma (BNL).

1.2 Physics

1.2.1 Higgs Discovery & Properties Measurements Program

H ! �� Discovery & Properties (Mott, Yang, Veverka, Bornheim, Apresyan, Newman,Spiropulu) The H ! �� decay channel is one of the principal discovery modes and provides asensitive means to determine the properties and couplings of the SM Higgs boson.

The discovery analysis in this channel relied on the foundations developed by the Caltechgroup, including the first boosted decision tree (BDT) analysis by Ma, the ECAL calibration with⇡0/⌘’s (Newman, Bornheim, Yang, Pena [201]) combined with the transparency measurementsfrom the laser monitor (Zhu, Zhang [202]), the regression based photon ID methods (Yang [204]),and the energy scale setting and the electron pixel veto e�ciency methods using tagged photonsin Z ! µµ� events (Veverka and Bornheim [203, 18]). Yang’s thesis [204, 68] (with Newman,

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1.2 Physics 4

Bornheim, Gataullin, Di Marco, Mott, and others in the group; completed in Nov. 2012) is theanalysis of this mode, illustrated in Fig. 1.1, that uses the most rigorous calibration and multivariateanalysis methods to improve the ECAL reconstruction of photon clusters. Gataullin and Ma playeda central role in the baseline CMS analysis e↵ort, both for the SM and the Fermiophobic Higgs [17].Mott, Ma, Gataullin, Bornheim and Veverka also made major contributions to the development ofthe diphoton triggers, optimization of the photon identification methods in the presence of pile-up [18] and modeling of the signal lineshape. Yang’s thesis contained an analysis of the variations ofresults based on bootstrap resampling methods as suggested by Newman, which later was appliedin simplified form to gauge the internal consistency of the Higgs results among analyses and runningperiods.

Since the discovery, the Caltech group (Mott et al.) has developed a substantially upgradedstreamlined H ! �� analysis that directly exploits a key strength - the high resolution for photons,evaluated in categories event by event. This has been achieved while eliminating multiple layersof the baseline MVA analysis, which mitigates the impact of mismodeling e↵ects in the simulationand other systematics. The new analysis provides a stable platform for accurate measurement andtesting deviations from the SM. This will be especially important during the 13-14 TeV run, whenthe rate of evolution of the ECAL and other subdetector responses will accelerate under greaterirradiation, and when this e↵ect combined with increased pileup (including out of time pileup with25 nsec bunch spacing) could a↵ect the trigger and DAQ performance.

Mott’s improved �� analysis is used in a novel set of Higgs-aware searches for SUSY and alsoprovides a natural connection with the upgrade of the forward ECAL. The measurement of theLagrangian parameters will be improved by selecting the high resolution photons (with varyinge�ciencies) throughout the entire acceptance of the ECAL. The upgrade described in Section 1.3will improve the photon identification and resolution in the ECAL endcap, and thus increase theoverall precision of these measurements. We note that Bornheim has led the CMS e↵ort to studythe performance of the H ! �� analysis with HL-LHC pile-up conditions.

H ! ZZ? ! 4` Discovery (Di Marco, Xie) Since 2012 the Caltech group has led, togetherwith the UCSD group, the optimization of the search for a low mass Higgs in H ! ZZ⇤ ! 4`.The high sensitivity in this channel depends crucially on reconstructing muons and electrons downto the lowest possible pT . The electron identification developed by Di Marco and Xie, suited forelectrons down to pT=7 TeV improved the signal sensitivity for mH < 130 GeV by 15-20% (Fig. 1.2left). Their introduction of regression for the momentum estimation of the electron, using bothECAL and tracker variables, led to an improvement of 20% in the mass resolution of the H ! 4echannel, and to observation of the new boson with 6.8� significance (6.8� expected) in the H ! 4`channel alone, as shown in Fig. 1.2 right.

Di Marco also had the principal role in the calibrations of the electron momentum scale andresolution using Z, J/ and ⌥(1S) resonances. He introduced corrections for the momentum scaleas a function of the electron ⌘ and pT , and reduced the scale systematics to less than 0.3%, asshown in Fig. 1.3 left. Di Marco is the main author of the measurement of the Higgs mass inthis channel, with a fit using per-event mass uncertainties calibrated with dimuon and dielectronresonances on data. Since 2013 Di Marco is the Coordinator of the H ! 4` group and Editor of thepaper. The Caltech group’s contributions to this measurement are documented in multiple CMSAnalysis Notes [125], a Physics Analysis Summary [121], and the 2012 and 2013 papers [120, 124].

H ! ZZ? ! 4` Properties (Chen, Xie, Di Marco, Spiropulu) In light of the upcoming 13 TeVrun, Caltech’s Chen et. al have developed a complete new analysis framework and computationalmethodology to measure the properties directly, thereby entering a new era of precision Higgsmeasurements. Starting from the e↵ective Lagrangian approach [207], and the fully di↵erential

1.2 Physics 5

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Figure 1.3: Left: Relative di↵erence between the dilepton mass peak position in data and simulation asobtained from Z, J/ and ⌥ resonances as a function of the transverse momentum of one of the electronsfor dielectron events in the 8 TeV data. Right: scan of the negative log-likelihood �2� ln L vs the SM Higgsboson mass mH , for each of the three channels separately and for the combination.

cross section for general scalar couplings to ZZ, ��, and Z� including interference e↵ects, allowingfor on- and o↵-shell gauge bosons and the qq background, and a fully parametrized map for thefinal state leptons that accurately reproduces the full detector acceptance and resolution, we havebuilt 8-dimensional reconstruction-level probability distributions (pdfs) as continuous functions ofthe Lagrangian parameters. Fig. 1.4 shows the SM background decomposition as a function of4-lepton mass for phase space cuts similar to CMS analysis: 40 GeV < MZ1 < 120 GeV, 10 GeV< MZ2 < 120 GeV with MZ1 > MZ2.

We have been recently able to perform a fit of the full SM Lagrangian to the data in a computa-tionally tractable manner for the first time, and directly extract simultaneously all the parametersand their correlations. An important advantage of this approach is that the observables we use tobuild the pdfs are well understood: lepton decay angles, dilepton masses and four-lepton masses.We do not contract them into lower dimension composite observables, and thus retain the full dis-crimination power and sensitivity in the measurements. The results of this analysis were presentedby Chen, and highlighted in the plenary sessions at ICHEP 2014.

This analysis also is expected to be an important benchmark in LHC Run 2, where we anticipatemuch smaller statistical errors in the extracted parameters. As an example, in Figure 1.4, we presentthe likelihood scan for a pseudo-dataset of 500 events for the lowest-order CP-odd HZZ couplingcomponent for a toy model point, labeled as the white diamond. In preparation for the study, Chenet al in collaboration with Vega-Morales produced a series of papers [119, 117, 118] documenting

1.2 Physics 6

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Figure 1.4: (Left) Decomposition of the SM background to the Higgs search for the 2e2µ final state. A:s-channel 2e2µ process B: t+u-channel �� C: t+u-channel ZZ D: t+u-channel Z� E: t+u-channel ZZ/Z�/��interference only F: ZZ/Z�/�� s/t-channel interference only; (Right) Example of the likelihood scan usinga pseudo-dataset of 500 events. The two axes are the magnitude and phase of the lowest order CP-oddoperator while fitting the parameters of the order-5 CP-even operators.

the analysis procedure, preliminary results with LHC data and projections, and the calculation andcomputational aspects of the analysis.

H ! WW? Discovery & Properties (Di Marco, Xie, Rogan, Newman, Spiropulu) TheH ! WW decay, with a fully leptonic final state, is the channel with the highest sensitivity forHiggs masses larger than 125 GeV. Di Marco has had the leading role in formulating and optimizingthis analysis in CMS, including the electron identification and analysis techniques to extract thesignal from the start. He served as the Coordinator of the HWW group, and has been the maincontributor throughout the 7 and 8 TeV LHC run. In 2012, Di Marco and Xie reoptimized theelectron identification and improved the methods to estimate W+jets from the data, to furthersuppress the background and more accurately extract the signal, with an observed significance of4.3 � (expected 5.0 �). Given the high branching ratio and good signal/background ratio (⇡ 1/10),we also obtained a measurement of the signal strengths that have implications for both the fermioncouplings and the vector couplings, shown in Fig. 1.5 left.

Given the presence of two neutrinos, the H ! WW channel provides sensitivity to the massmainly through the variation of the cross section with mH. Di Marco, Rogan and Spiropulu appliedan alternative innovative approach to this channel, using an updated version of the razor variableMR [20], and the opening angle of the two leptons in the razor frame, ��R. This improvesthe mass resolution from an e↵ective 30 GeV to 20 GeV, peaking at the true Higgs mass. Theanalysis also uses a di↵erent experimental technique, through a 2D unbinned maximum likelihoodapproach [126]. The S/(S+B) weighted, background subtracted MR distribution for 7 and 8 TeVdata is shown in Fig. 1.5 middle. This technique, as a fully parametric shape analysis, has beenapplied to measure the mass of the observed boson in this channel in the SM hypothesis (µ ⌘ 1)with remarkable precision: mH = 125.5 ± 3.8 GeV, consistent with the mass measured in theH ! �� and ZZ ! 4` channels. The 2D likelihood contour in the µ�mH plane is shown in Fig. 1.5right. This analysis also has improved the precision of the WW SM cross section measurements,and established additional handles to improve the overall Higgs spin measurement through fulluse of the charge and helicity information in the W decays in this channel. Caltech’s studies in2013 using 8 TeV data are described in the CMS Analysis Notes [126, 127], the Physics AnalysisSummary [122] and the paper being submitted as of this writing [123].

H ! Z� Sensitivity and Implications (Bornheim, Xie, Veverka, Pena, Newman) The Higgsboson decay to Z� proceeds through a loop mediated by heavy charged particles at leading order,and is therefore particularly sensitive to contributions from BSM physics. The Caltech group led

1.2 Physics 7

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are weighted according to S/(S+B) in each corresponding bin of the histogram. Right: Confidenceintervals in the (�/�SM ,mH) plane using the fit in the MR-��R distribution, where the solid anddashed lines indicate the 68% and 95% CL contours respectively.

the work on this search as documented in [209]. Xie led the improvement and optimization ofthe lepton selection, as well as the measurement of the selection e�ciency. Bornheim and Xie ledthe improvement of the lepton momentum and photon energy measurements. Bornheim and Penaevaluated and precisely corrected the scale and resolution of the photon energy measurement [210]using the Phosphor fit invented by Veverka to measure photon energy scale and resolution in-situusing radiative Z boson decays to muons Z ! µ+µ��. The wide-ranging work and leadershipof Bornheim in this important area of Higgs physics, as well as the associated work on correctlygauging the scale and resolution are particularly noteworthy.

The limit we set is 3 to 31 times the SM cross section, depending on the mass. A few hundredinverse femtobarns is needed to reach the SM cross section, and a few inverse attobarns is neededto measure the cross section in this decay channel. A significant increase in e�ciency could beachieved by extending the usable kinematic range for photons to larger ⌘ and lower pT , throughthe upgrades discussed in Section 1.4.

Higgs combination (Xie, Chen) The properties of the Higgs boson are best studied when allproduction and decay channels are considered simultaneously and the systematic uncertainties areappropriately correlated. As part of the CMS combination team, Xie and Chen contributed to thedevelopment, implementation, and validation of the benchmark e↵ective physics models, includingevaluation of possible fit biases. Their work focused on measuring the e↵ective Higgs couplings foreach of the benchmark models [211, 212], exemplified by the measurement of the vector (V) andfermion (F) couplings to the Higgs boson. This is shown in Fig. 1.6, along with their results ontesting custodial symmetry using the WW and ZZ decay channels.Double Higgs Production Future Projections (Xie, Lambert, An) Measuring the crosssection for double Higgs boson production is the only method available at the LHC to construct theshape of the scalar potential, including the Higgs self-coupling, which has profound implications inparticle physics and cosmology. Measuring this highly-suppressed process is a challenge, requiringleast 100 times more integrated luminosity than was collected during LHC Run 1, which makes itan ideal benchmark to motivate the HL-LHC and study the particular technology choices for theCMS Phase 2 detector upgrade. Xie and undergraduates An and Lambert carried out the firstcomprehensive simulation study of the double Higgs channel HH ! bb�� in CMS, including thecomplete set of backgrounds. They established the feasibility and characterized the sensitivity ofthis measurement [128, 129] through a maximum likelihood fit they developed to extract the signal

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Figure 1.6: Left: Exclusion limits on the cross section times branching fraction for H ! Z� relative to theSM prediction. Middle: The 68% CL contours for the measurement of the vector (V) and fermion (F)couplings to the Higgs boson for individual decay channels (colored regions) and for the combined result(gray region). The 95% SL contour for the combined result is shown as the thin dashed line. The crossindicates the best-fit values and the yellow diamond indicates the SM values. Right: The likelihood scan vs�WZ, the ratio of the Higgs boson couplings to the W and Z bosons. The solid curve is the data, and thedashed line is the expected median SM result. Crossings with the horizontal red lines denote the 68% CLand 95% CL intervals.

Figure 1.7: (Left) diHiggs production cross section for di↵erentps (Middle) The uncertainty on the double

Higgs boson production cross section measurement using 3 ab�1 of integrated luminosity at the LHC, asa function of the width of the di-bjet mass distribution. (Right) The same cross section measurementuncertainty as a function of the integrated luminosity.

cross section, using the diphoton mass and di-bjet mass. Their results, expressed as the relativeuncertainty on the measured cross section as a function of the photon and jet energy resolution,and the integrated luminosity, shown in Figure 1.7, are important in establishing the means bywhich future studies of detector performance based on more detailed simulations, including re-optimizations of b-tagging performance and jet energy resolution in the HL-LHC environment, canbe easily mapped onto the ultimate sensitivity to the Higgs self-coupling parameter.1.2.2 Razor Searches: SUSY, Exotica & Dark Matter

The razor variables and their phenomenology were conceived, invented and developed withinthe Caltech group with colleagues from FNAL and CERN, and a large number of new analysesare being carried out in CMS and ATLAS as well as by the theory and phenomenology commu-nity using these ideas. Rogan’s Ph. D thesis (completed February 2013) focused on this powerfulsearch program by exploiting kinematic variables sensitive to the mass-scale of pair-produced par-ticles decaying to visible and weakly interacting particles, as is characteristic of Supersymmetryand a number of New Physics scenarios that include a Dark Matter candidate. In October 2013we hosted a workshop on new kinematic variables at Caltech (http://hep.caltech.edu/kvnp) thatfurther explored the multifaceted application of razor and razor-like approaches to: BSM searches,Higgs characterization, and in depth understanding and description of SM physics, especially topand vector boson QCD associated production.

Caltech led the most inclusive LHC search for new heavy particle pairs produced atps =

7 TeV. A summary was just published in Phys. Rev. Letters [132], and article has been publishedin Phys. Rev. D. The search used a 2D shape analysis in the razor space of R2, a dimensionless

1.2 Physics 9

ratio related to the missing transverse energy�ET , and MR, an event-by-event indicator of the heavy

particle mass scale. Our razor results from the full 2012 dataset were highlighted at SUSY2013 andICHEP 2014. The latest results, using an upgraded razor analysis led by Duarte that includes thenumber of b-tags in the event as a third dimension in the likelihood, put the most stringent limitson the masses of stops and gluinos, and raise concerns on “naturalness” as the path to solving thehierarchy problem.

Gluinos and top squarks (Duarte, Chen, Apresyan, Di Marco, Mott, Pierini, Spiropulu) Thesesearches exploit the razor variables R2 and MR [135, 136] to separate the SM background (mainlyW/Z+jets and tt+jets) from a potential signal (a bump on a falling spectrum in the R2 vs. MR

plane). The background-only hypothesis, specified through an 3-dimensional analytical model, is ingood agreement with the data. The results (available at twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS13004) are interpreted in terms of exclusion limits on the masses of SUSY par-ticles, using a set of simplified SUSY models [137, 138, 139]. Fig 1.8 shows the 95% C.L. upperlimit on the gluino and top squark production cross sections we obtained as a function of theirmasses in two simplified SUSY scenarios, as shown at the SUSY2013 conference, which were themost stringent limits on these sparticle masses up to that date.

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Figure 1.8: (Left) 95% C.L. upper limit on the gluino production cross section times branchingfraction as a function of gluino mass (for a fixed LSP mass of 50 GeV) in a simplified SUSY topology,consisting of gluino-mediated production of 4 b-jets with missing transverse energy. (Right) 95%C.L. upper limit on the stop production cross section times branching fraction as a function ofthe stop mass (for a fixed LSP mass of 25 GeV) in a simplified SUSY topology, consisting ofstop-mediated production of 2 top quarks with missing transverse energy.

Natural SUSY (Duarte,Pierini, Spiropulu) In 2014 we produced a new set of interpretationsof the razor analysis using a simplified natural SUSY spectrum as a reference. In the context ofthis benchmark the neutralino is forced to be the lightest SUSY particle. The di↵erence in massbetween the chargino and the neutralino is fixed to 5 GeV. Gluino and same-flavor squark pairproduction are considered in separate models, scanning the masses of the produced SUSY particleand the neutralino.

For the top squark, the combined likelihood of the razor hadronic analysis and the exclusivetop squark search in events with single-lepton results in a stronger bound on the top squark mass.These analyses and combinations are now heading for publication and are publicly available attwiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsSUS14011

Dark Matter (Pena, Duarte, Pierini Spiropulu) CMS’ DM searches using monojet [40] andmonophoton [41] events (with large

�ET and a single photon or jet) are known to be competitive with

direct and indirect DM searches, and are the most sensitive for low masses in the Spin Independent(SI) case, as well as for a wide range of masses in the Spin Dependent (SD) case. We haveapplied new razor-based methods to monojet and monophoton events as sensitive probes of BSMphysics [42], with e↵ective field theory as a DMmodel framework, to extend the reach and sensitivityof these searches by exploring a more inclusive multijet topology in a previously unexplored region

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Figure 1.10: (Left) Spin dependent DM-nucleon cross section upper limit as a function of the DMmass. (Right) Spin independent DM-nucleon cross section upper limit as a function of the DMmass. The CMS razor and CMS monojet analysis results are shown as dashed lines while otherdirect DM experimental limits and future projections are shown as solid lines.

of parameter space. The preliminary limits from our analysis of the 8 TeV dataset are shown inFig 1.10) along with other CMS and Xenon results. The razor analysis on the full Run 1 dataset,is now being internally reviewed towards publication as of this writing and will further narrow thesearch for dark matter.

3rd generation leptoquarks, and sbottoms (Chen, Apresyan, Spiropulu) Our group hasperformed the first search at the LHC for third generation Leptoquarks (LQ) that carry bothbaryon and lepton numbers, in events with large

�ET and b-jets. We have set the most stringent

limits on third generation LQs, excluding masses below 450 GeV, and the first stringent limits onsbottom production, excluding sbottom squark masses up to 410 GeV. These analyses have beenpublished in Ref. [216].

Other analyses with the razor framework include a search in events with � 6 jets [214], in tauleptons [130], and in di-photons photons [131], each of which is designed to target interesting BSMphysics, such as light stops in SUSY, light staus, gravity-mediated SUSY breaking, and Kaluza-Klein gravitons.

Resonant Diphoton Razor Analysis (Mott, Spiropulu) Here we search for SUSY events in8 TeV LHC collisions using the razor variables and selecting events with a pair of photons whoseinvariant mass is near the Higgs resonance. The search uses Standard Model Higgs Monte Carlo andsidebands in the m�� spectrum to predict the background shape in the R2 �MR plane for eventsnear the Higgs mass peak. The analysis is done in five exclusive boxes based on event kinematics,photon quality and the presence of bb pairs to improve sensitivity to a wide variety of models. Theselection is left as inclusive as possible, to allow interpretation of a wide set of SUSY models with

1.3 Detector Subsystems and Upgrades 11

Higgses in the final states. This analysis is the focus of the thesis of graduate student Alex Mott,and it will soon enter internal review towards publication.

Recursive Razor & other Razor framework upgrades (Duarte, Rogan, Pierini, Spiropulu)An e↵ort to develop the razor framework further targeting searches of models with “compressedspectra”, i.e. small mass splittings between the new heavy partners is underway. We refer to thisas the recursive rest-frame (RR) reconstruction, introduced in Rogan’s thesis [20]. Since 2012,this approach has been further developed by Duarte and Spiropulu with undergraduates Wangand Upadhya, and has been shown to provide a handle on the spectroscopy of all the particlesin the decay chain. A phenomenological study with collaborators Lykken (FNAL) and Buckley(Rutgers) used the new approach in direct searches for electroweak pair production of new particlesat the LHC. Despite the large background and low signal cross sections we demonstrated how thesesearches can be improved by a combination of new razor variables and shape analysis of signal andbackground kinematics, in final states with a pair of opposite sign leptons plus missing transverseenergy. The work was published at PRD (10.1103/PhysRevD.89.055020) in 2014. Additionally theteam has been working on optimization of the megajet reconstruction algorithms to more accuratelycapture the products in each decay chain in the pair production and deacys of new heavy partners.Undergraduate Edward Garza is working on this topic with Wang at the time of this writing, andthey are marking good progress.

Razor SM backgrounds: W+jet, Z+jet and tt+jets events (Anderson, Lee, Spiropulu,Newman) The Caltech group has had a central role in the thorough understanding and study ofthe SM production of W+jets, Z+jet and tt+jets processes as the foundation of all searches for theHiggs and BSM physics, as well as an invaluable training ground for starting undergraduates andgraduate students in hadron collider physics and precision QCD measurements. We have led theCMS preparation and first papers on W+jets and Z+jets in both the electron and muon channels,and we have launched a new e↵ort to study these SM processes using the razor framework inpreparation for the 2015 Run 2 searches for new physics. Graduate student Dustin Anderson haspresented results on Z+jets and tt+jets using the razor variable space with the 8 TeV data. Givenhis involvement and rapid progress in both the Standard Model and SUSY groups, he has beenasked recently to be the main contact for the validation of the mini-AOD event format in CMS, aswell as the main SUSY/PPD/DQM contact.

1.3 Detector Subsystems and Upgrades

Electromagnetic Calorimeter (ECAL) The ECAL performance relies on precise (laser) mon-itoring and (⇡0/⌘0) calibration, and in-depth understanding of detector and monitoring systematice↵ects on a crystal-by-crystal basis over time. Caltech leads the work in these areas. The crystalsof the CMS ECAL exhibit a dose rate dependent transparency change ranging from a few percentin the barrel to several tens of percent in the endcap. To compensate for the resulting deteriorationof the resolution performance the transparency is measured with a sophisticated laser monitoringsystem and corrected to a precision of around 0.1%. Caltech designed the laser source, installed,commissioned and optimized it at CERN (Zhu, Zhang, Bornheim), and maintains this mission crit-ical device (Bornheim, Di Marco and students). In 2012-13 the old Quantronix lasers were replacedwith state of the art diode pumped lasers from Photonics Industries, that were first commissionedat Caltech before installation at Point 5.

The monitoring of the transparency changes is now a stable and reliable procedure. The focushas now shifted to longterm measurements of the performance of the crystals, in the higher radiationenvironment of the endcap during Run 2, which will also provide important input for our HL-LHC studies and preparations for the CMS Phase 2 Upgrades. The ⇡0/⌘0 calibration, performed

1.3 Detector Subsystems and Upgrades 12

since 2012 by Pena and Bornheim, is now automated and streamlined. The calibration resultsprovide crucial input to the Higgs to diphoton discovery channel. During the shutdown we usedboth the laser monitoring and (⇡0/⌘0) calibration data crystal by crystal as part of the continuedoptimization work on our upgraded H! �� analysis.

Hadron Calorimeter (HCAL) The HCAL is the essential subsystem for jet and�ET recon-

struction, crucial for all discovery analyses with jets (such as Dark Matter searches, Higgs andother VBF measurements.). Caltech (Apresyan, Chen, Mott and Spiropulu) led the work on theHCAL noise filtering at the trigger, online and o✏ine reconstruction levels, as well as all the dataquality monitoring (DQM) since 2009. Preparing for LHC Run 2 with higher luminosity, the focusof the HCAL noise group, led by Chen, has been two-fold: upgrading the baseline noise filters,and developing a new pileup-insensitive energy reconstruction. Chen (with A. Toropin) used aparameterized model of the HCAL pulse shape from the pileup deposits in minimum bias eventsto subtract the out-of-time (OOT) pileup. He derived a correction from this model and was ableto eliminate the bias in the energy measurement. The Caltech noise filters we developed for Run1 [153] based on pulse shape have been upgraded to provide the overall likelihood of a readout boxbeing noisy, while the filters we developed that use the number of hits above energy threshold arebeing reoptimized for high pileup conditions during Run 2.

One of the major CMS upgrade projects during Long Shutdown 1 (LS1) was the replacementof the photodetectors of the outer hadron calorimeter (HO) with silicon photomultipliers (SiPMs),providing significantly improved stability and a higher signal to noise ratio. Xie established a leadrole in the project by coordinating the entire SiPM quality certification team in the operationof the front-end readout module burn-in teststand, as well as the analysis of the resulting qualitycertification data. He developed and improved many of the analysis methods, including the analysisof the long term stability of the SiPM readout modules from which a number of issues significantfor its operation in the next LHC run have been discovered. He led the e↵ort to define the criteriafor SiPM certification, and successfully installed and set up the teststand for operation at the CMSassembly hall at Point 5. Prior to and during Run2, Xie will play a leading role in commissioningHO and developing new methods and algorithms to exploit the improved detector, to achieve therequired triggering and energy measurement resolution. Notably Spiropulu, Chen and Apresyanhave been asked by the CMS management in the Summer of 2014 to assist the HCAL DPG groupin aspects of detector performance and noise filtering technology transfer and oversight in view ofthe upcoming Run 2.

Trigger (Duarte, Wang, Mott, Pierini, Chen, Rogan, Spiropulu) Since 2010, Caltech hashad major development, deployment and operational roles in the CMS trigger group, in additionto designing new physics-motivated trigger suites (such as the razor suite for searches and thediphoton suite for the Higgs) and the filters that mitigate HCAL noise at the trigger level. Forthis work Mott was awarded one of the 7 subsystem detector awards in 2011. In 2012-13, Mottcontinued his work designing, deploying and validating all 25 physics trigger menus (each containinghundreds of trigger paths) and over 40 special purpose (for example calibration, alignment etc.)run configuration menus used by CMS. The high level trigger (HLT) monitoring software suitedeveloped by Mott was deployed as the sole tool for online monitoring of the HLT, as well as allHLT data-certification and validation. His HLT suite, which has been successful in quickly spottingand immediately resolving a number of data quality issues to ensure the data quality during LHCRun 1, will be extended to cover the more di�cult conditions of LHC Run 2.

The Caltech group also is developing special triggers for Higgs properties measurements in thedi-photon channel, and more sophisticated versions of the razor trigger suite to maintain and extendCMS’ sensitivity to BSM phenomena amidst the more challenging luminosity and pileup conditions

1.4 Upgrade of the CMS detector for HL-LHC 13

of Run 2. Ann Wang with Duarte have presented a comprehensive proposal to the trigger studiesgroup that is incorporated in the trigger menus that are being currently designed for the upcomingRun.

1.4 Upgrade of the CMS detector for HL-LHC

The HL-LHC is planned to provide 2.5 inverse attobarns with instantaneous luminosities leveledat 5 ⇥ 1034cm�2s�1, corresponding to a peak pileup of 140 minimum bias collisions per bunchcrossing, starting approximately in 2025. Precision measurements of the recently discovered Higgs-like particle and the mechanism of electroweak symmetry breaking will be major physics goals, aswell as continued searches for new physics with greatly extended reach.

Upgrade of the CMS forward detector region (Newman, Bornheim, Apresyan, Di Marco,Duarte, Anderson, Flamant, Pena, Zhu) The Technical Proposal for the CMS Phase 2 Upgrade [106]includes a forward ECAL upgrade to address the degradation induced by electromagnetic andhadronic radiation in the crystals [104, 232] and readout devices. The Caltech group has leadingroles in R&D for the ECAL upgrade that build on the group’s ongoing R&D program on LYSOcrystals [108, 109, 110, 111, 112, 233]. Recent studies by Zhu et al. have shown that these crystalsare radiation hard up to the electromagnetic dose levels (⇠ 100 MRads) expected in the ECALendcap at the HL-LHC. (Additional discussions of crystal R&D at Caltech are found in the CrystalDetector R&D Chapter of this report.) Figure 1.11 (Left) shows the concept, a very compact LYSO+ Tungsten sampling “Shashlik” calorimeter with longitudinal fibers to extract the light, designedand proposed by our group for the Phase 2 CMS endcap ECAL [113], that would have the neededradiation hardness and resolution. The design has the advantages of a small Moliere radius (14mm) for superior electromagnetic shower containment and hence photon ID in the presence of highpileup, short length (12 cm of LYSO and W layers for 24 X0) and high light output per GeV. Afirst Shashlik prototype matrix has been constructed in collaboration with Virginia, Notre Dame,Minnesota, Iowa and other CMS collaborators, and has been successfully tested at the FermilabM4 test beam this Spring and Summer. Caltech’s participation in the test beam campaign atFermilab using a Shashlik test matrix and precision timing devices (as discussed next), includesbenchmarking the performance of the detectors and understanding their combined use in this newregime, as well as guiding the R&D process towards a full scale detector upgrade for the HL-LHC.

PU=20PU=140PU=140, 'tmax(jet) 150 ps

VT = 10 ps

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Figure 1.11: (Left) LYSO/W sampling calorimeter forward ECAL concept for the HL-LHC. (Middle)

tz-vertex resolution as measured with the time-of-flight (TOF of all energy deposits in a jet) for a dijetsignature. (Right) Monte Carlo simulation of tz-vertex resolution in events where the Z boson decays to apair of electrons, measured with a varied TOF resolution.

Picosecond TOF system (Spiropulu, Bornheim, Apresyan, Xie, Duarte, Pena, Anderson,Flamant, Newman, Zhu) Following Spiropulu’s proposal (Alushta 2011) to include a precisiontiming detector in the CMS Phase 2 Upgrade program, studies by our group have shown how ahigh resolution timing detector could provide the necessary handles to distinguish energy depositsfrom pileup, and optimize physics object reconstruction at HL-LHC. This program has already

1.4 Upgrade of the CMS detector for HL-LHC 14

Figure 1.12: Measurements ofthe time resolution for di↵erentelectron beam energies, obtainedwith an LYSO crystal mountedon a Hamamatsu R3809 MCP-PMT, fitted to a model incorpo-rating a stochastic term scalingas 1/

pE, and a constant term.

shown the promise of this approach to improve the object ID, energy resolution and correct vertexID e�ciency by (1) discriminating and suppressing physics objects or components of objects fromPU, (2) cleaning up ECAL calorimeter clusters based on the shallower depth and hence earliertimes of min-bias (PU) hits in the crystals, for photons that have no associated tracks, as well asfor electrons, (3) identifying the hard scatter vertex for neutral objects by finding a set of timesconsistent with a single z-vertex position after correcting for the candidate flight path, (4) improvingthe �/⇡0 separation through a similar method, and (5) distinguishing spatially overlapping verticesthat are separated in time.

Spiropulu with the Caltech team have launched an R&D program, referred to as CPT (CMSPrecision Timing) towards the feasibility, development and construction of a high precision timingsystem for the Phase 2 CMS upgrade. The progam includes both a strong simulation e↵ort anda strong hardware R&D e↵ort. The goals of the precision timing system include excellent energyresolution and identification e�ciency for photons, electrons, jets and missing transverse energyin the extreme pileup environment of the High Luminosity LHC run. We are investigating twooptions for calorimeter elements capable of high precision timing: a) scintillating crystal layers asan active medium to detect the energy and position of the high energy particles and their time ofarrival simultaneously [234], and b) a dedicated detector based on microchannel plates (MCP) tomeasure secondary shower particles [235]. The benefit of precision timing on the physics objectreconstruction in the HL-LHC environment has been studied in the context of preparations of theCMS Phase 2 upgrade Technical Proposal, and is documented in Section 9 of the correspondingdocument [236]. To be utilized e↵ectively it has been found that the timing measurement needs tobe very closely linked to the electromagnetic energy measurement, ideally based on the same activedetector element.

In the past year we have conducted several rounds of experiments at Spiropulu’s CPT Lab inLauritsen, using the lab’s cosmic ray and picosecond laser test stands), and at the Fermilab testbeam facility, to investigate the feasibility of the precision calorimeter options. To perform theseexperiments, we have utilized the resources provided by the Caltech PMA division, funding from USCMS (that prompty recognized the value of this line of R&D work), as well as sharing of resourceswith the precision timing group at Fermilab. Our results have been widely presented within theCMS collaboration, as well as at international conferences (CALOR 2014, TIPP 2014, NDIP 2014),and have been published in NIM A [235]. The results are indeed very encouraging. Based on themost recent test beam results, we now have a proof of concept of the technical feasibility of a devicecapable to achieve a resolution of a few tens of psec, as shown in Figure 1.12.

At the August 25, 2014 CMS Management Board, the CMS upgrade management recognizedthe importance of the timing R&D, and proposed the formation of a CMS Fast Timing WorkingGroup. We have been contacted as initiators and leaders of this work to advise on the selection of a

1.4 Upgrade of the CMS detector for HL-LHC 15

coordinator of this group. To form a fast timing upgrade project with international participation,we plan to work closely with our CERN and European colleagues who have expressed interest inour timing R&D program during the past year.

[1] E. Di Marco et al., “Search for the Higgs boson decaying to WW in the fully leptonic final stateat 8 TeV,” CMS Note, 2012.

[2] E. Di Marco et al., “Search for the Higgs boson decaying to WW in the fully leptonic final stateat 8 TeV,” CMS Note, 2012.

[3] E. Di Marco et al., “Higgs boson decaying to WW in the leptonic final state using 2011 and2012 data,” CMS Note, 2013.

[4] CMS Collaboration, “Search for the standard model Higgs boson decaying to W+W� in thefully leptonic final state in pp collisions at

ps = 8 Tev,” CMS PAS, 2012.

[5] CMS Collaboration, “Search for a standard-model-like Higgs boson with a mass of up to 1 TeVat the LHC,” CMS PAS, 2012.

[6] CMS Collaboration, “Evidence for a particle decaying to W+W- in the fully leptonic final statein a standard model Higgs boson search in pp collisions at the LHC,” CMS PAS, 2012.

[7] CMS Collaboration, “Update on the search for the standard model Higgs boson in pp collisionsat the LHC decaying to W+W- in the fully leptonic final state,” CMS PAS, 2013.

[8] E. Di Marco et al., “Search for the Higgs boson in W+W� ! 2l2⌫ in pp collisions atps=7 TeV

with razor variables,” CMS Note, 2012.

[9] E. Di Marco et al., “Higgs boson decaying to WW in the leptonic final state measurement usingrazor variables,” CMS Note, 2013.

[10] E. Di Marco et al., “Search for the standard model Higgs boson in the decay channel H !ZZ ! 4 leptons with 10.3 fb�1 of data,” CMS Note, 2012.

[11] E. Di Marco et al., “Spin measurements of the new boson observed around 125 GeV,” CMSNote, 2012.

[12] E. Di Marco et al., “Observation at 4.5 standard deviations of a standard model Higgs-likeboson with mass mh = 126.2 ± 0.7 GeV,using H ! ZZ ! 4l events with 17.3 fb�1 of data atps = 7 and 8 TeV,” CMS Note, 2012.

[13] E. Di Marco et al., “Study of the resonance with mass 126 GeV in the context of the searchfor the standard model Higgs boson in the decay channel H ! ZZ ! 4` in pp collisions atps=7 TeV and 8 TeV and measurements of its properties,” CMS Note, 2012.

ii

iii

[14] CMS Collaboration, “Evidence for a new state in the search for the standard model Higgsboson in the H ! ZZ ! 4` channel in pp collisions at

ps = 7 and 8 TeV,” CMS PAS, 2012.

[15] CMS Collaboration, “Updated results on the new boson discovered in the search for the stan-dard model Higgs boson in the H ! ZZ ! 4` channel in pp collisions at

ps = 7 and 8 TeV,”

CMS PAS, 2012.

[16] CMS Collaboration, “Properties of the Higgs-like boson in the decay H ! ZZ ! 4` in ppcollisions at

ps = 7 and 8 TeV,” CMS PAS, 2013.

[17] M. Gataullin et al. “Search for a Higgs boson decaying into two photons in proton-protoncollisions recorded by the CMS detector at the LHC”AN-2011/206

[18] A. Bornheim, M. Gataullin, J. Veverka, “Photon Pixel Match Veto E�ciency MeasurementZ ! µµ� Events Selected at 7 TeV” AN-2011/089

[19] CMS Collaboration, “Search for the standard model Higgs boson decaying into two photonsin pp collisions at

ps = 7 TeV, Phys. Lett. B 710, 403 (2012)

[20] C.S.Rogan Ph.D Thesis, “Searches for new symmetries in pp collisions with the razor kinematicvariables”, Caltech (2013) http://thesis.library.caltech.edu/7671/

[21] Joe Lykken Maria Spiropulu Roberto Vega-Morales Yi Chen, Emanuele DiMarco and Si Xie.Directly Extracting the ZZ Couplings of the Higgs Boson in the Golden Channel.

[22] Joe Lykken Maria Spiropulu Roberto Vega-Morales Yi Chen, Emanuele DiMarco and Si Xie.Directly Extracting the ZZ Couplings of the Higgs Boson in the Golden Channel: TechnicalDetails.

[23] Shashank Shalgar Yi Chen, Kunal Kumar and Roberto Vega-Morales. Re-Scrutinizing theHiggs Signal and Background in the Golden Channel.

[24] E. Di Marco et al. “Electron reconstruction in CMS” AN-2009/164

[25] CMS Collaboration, “Measurement of W+W� production and search for the Higgs boson inpp collisions at sqrt(s) = 7 TeV”, Physics Letters B 699, 25 (2010)

[26] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, EPS 2011 dataset” AN-2011/148

[27] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, EPS 2011 dataset” AN-2011/201

[28] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, LP 2011 dataset” AN-2011/364

[29] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, 4.6 fb-1” AN-2011/432

[30] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, 4.6 fb-1, cut based analysis” AN-2011/460

[31] E. Di Marco et al. “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, 4.6 fb-1, shape analysis” AN-2011/463

iv

[32] CMS Collaboration, “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, EPS 2011 dataset”, CMS PAS 2011/003

[33] CMS Collaboration, “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, LP 2011 dataset”, CMS PAS 2011/014

[34] CMS Collaboration, “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, 4.6 fb-1”, CMS PAS 2011/024

[35] CMS Collaboration, “Search for the Standard Model Higgs Boson in the WW decay with thefully leptonic final state, 4.6 fb-1”, Phys. Lett. B 710 (2012) 91-113

[36] S. P. Martin, “A Supersymmetry primer,” In *Kane, G.L. (ed.): Perspectives on Supersym-metry II* 1-153 [hep-ph/9709356].

[37] J. L. Feng, “Dark Matter Candidates from Particle Physics and Methods of Detection,” Ann.Rev. Astron. Astrophys. 48, 495 (2010) [arXiv:1003.0904 [astro-ph.CO]].

[38] Search for Pair Production of Third-Generation Scalar Leptoquarks Using Events Producedin pp Collisions at

ps = 7 TeV Containing b-jets and Missing Transverse Energy, CMS-EXO-

11-003.

[39] A. Apresyan, Y. Chen, J. Duarte, J. Hardenbrook, E. Di Marco, J. D. Lykken, A. Mott,T. Orimoto, M. Pierini C. Pena, W. Reece, C. S. Rogan, E. Salvati, S. Sekmen, M. Spiropulu,and S. Vijay. CMS Analysis Note (AN-12-259): Search for Dark Matter direct production in 8TeV p-p collisions with the Razor variables. 2012.

[40] CMS Collaboration. Search for dark matter and large extra dimensions in monojet events inpp collisions at

ps = 7 TeV. 2012.

[41] CMS Collaboration. Search for Dark Matter and Large Extra Dimensions in pp CollisionsYielding a Photon and Missing Transverse Energy. 2012.

[42] Patrick J. Fox, Roni Harnik, Reinard Primulando, and Chiu-Tien Yu. Taking a Razor to DarkMatter Parameter Space at the LHC. 2012.

[43] CMS Collaboration. Search for supersymmetry with taus using the razor variables. CMS PAS,2012.

[44] CMS Collaboration. Search for supersymmetry with photons using the razor variables”, journal=.

[45] Serguei Chatrchyan et al. Inclusive search for supersymmetry using the razor variables in ppcollisions at

ps = 7 TeV. 2012.

[46] J. Duarte et al. Inclusive razor search for susy atps = 8 TeV with 19.3 fb�1. CMS Note,

2013.

[47] CMS Collaboration. Inclusive razor search for squarks and gluinos in events with b-jets atps = 8 TeV. CMS PAS, 2013.

[48] C. Rogan. Kinematics for new dynamics at the LHC. 2010. CALT-68-2790.

v

[49] Serguei Chatrchyan et al. Inclusive search for squarks and gluinos in pp collisions atps =

7 TeV. Phys. Rev. D., 85, 2012.

[50] Johan Alwall, Philip Schuster, and Natalia Toro. Simplified Models for a First Characterizationof New Physics at the LHC. Phys. Rev., D79:075020, 2009.

[51] Johan Alwall, My Phuong Le, Mariangela Lisanti, and Jay G. Wacker. Searching for gluinosat the Tevatron and beyond. Int. J. Mod. Phys., A23:4637–4646, 2008.

[52] Daniele Alves, Nima Arkani-Hamed, Sanjay Arora, Yang Bai, Matthew Baumgart, et al. Sim-plified Models for LHC New Physics Searches. 2011.

[53] Zhao-Huan Yu, Xiao-Jun Bi, Qi-Shu Yan, and Peng-Fei Yin. Detecting light stop pairs incoannihilation scenarios at the LHC. 2012.

[54] Karol Krizka, Abhishek Kumar, and David E. Morrissey. Very Light Scalar Top Quarks at theLHC. 2012.

[55] Antonio Delgado, Gian F. Giudice, Gino Isidori, Maurizio Pierini, and Alessandro Strumia.The light stop window. 2012.

[56] Hyun Min Lee, Veronica Sanz, and Michael Trott. Hitting sbottom in natural SUSY. JHEP,1205:139, 2012.

[57] Ezequiel Alvarez and Yang Bai. Reach the Bottom Line of the Sbottom Search. JHEP,1208:003, 2012.

[58] J. Duarte et al. Search for direct stop production at 8 TeV with the razor. CMS Note, 2013.

[59] CMS Collaboration. Search for direct stop production at tps = 8 TeV with the razor. CMS

PAS, 2013.

[60] V. Timciuc, “Di-Electron Mass Resolution and Energy Scale”, (Exotica Resonances Meeting),https://indico.cern.chcontributionDisplay.py?contribId=2&confId=142182

[61] V. Timciuc, “Electron Energy Scale and Dielectron mass Resolution with 4.7 fb-1”, (HighMass Dielectron Meeting),https://indico.cern.chcontributionDisplay.py?contribId=0&confId=163111

[62] A. Bornheim et al., “Measurement of the CMS ECAL scale and resolution performance fromZ! �� decays and determination of the signal line shape for H ! ��”, CMS AN-2011/204

[63] V. Timciuc, “Pre-approval Z’ analysis (EXO-11-019)”, (Physics Plenary during CMS week 27June - 1 July),https://indico.cern.chcontributionDisplay.py?contribId=9&confId=143977

[64] CMS Collaboration, “Search for Resonances in the Dilepton Mass Distribution in pp Collisionsat

p(s) = 7 TeV”, (Summer 2011), CMS PAS EXO-11-019

[65] Christoph Englert et al. “Autofocusing searches in jets plus missing energy”, Phys. Rev D 83,095009 (2011).

[66] Zvi Bern et al “Precise Predictions for W+4-Jet Production at the Large Hadron Collider”Phys. Rev. Lett. 106, 092001 (2011).

vi

[67] B. Clerbaux et al.,”Search for High-Mass Resonances Decaying to Electron Pairs in the CMSExperiment”, CMS AN-2011/159

[68] Y. Yang et al. “ECAL calibration, photon energy scale, photon resolution performance andsystematic e↵ects of cluster corrections : impact on the Standard Model H ! �� search”, CMSAN-2012/214

[69] V. Timciuc, for the CMS Collaboration , “Search for High-Mass Resonances in the Dilep-ton Final State with the CMS Detector.”, XXXI Physics In Collision 2011 Proceedings,arXiv:1111.4528 hep-ex, CMS CR-2011/273

[70] CMS Collaboration, “Search for Resonances in the Dilepton Mass Distribution in pp Collisionsat

p(s) = 7 TeV.” CMS PAPER EXO-11-019 (now in Collaboration Wide Review)

[71] CMS Collaboration, “A search for excited leptons in pp Collisions at sqrt(s) = 7 TeV,” Phys.Lett. B 704, 143 (2011).

[72] E. Di Marco et al. “W+jets and Z+jets studies with 2011A data” AN-2012/508

[73] A. Bornheim, O. Bondu, S. Gascon-Shotkin, M. Gataullin, H. B. Newman, J. Veverka. PhotonEnergy Scale Studies with Z ! µµ� Events Selected at 7 TeV. CMS Analysis Note, CMS-AN-2011-088, 2011.

[74] J. Veverka, A. Bornheim, M. Gataullin. Photon Pixel Match Veto E�ciency Measurementwith Z ! µµ� Events Selected at 7 TeV. CMS Analysis Note, CMS-AN-2011-089, 2011.

[75] T. Bolton, et al. Measurement of inclusive W� and Z� cross sections and limits on anomaloustrilinear gauge boson couplings at 7 TeV. CMS Analysis Note, CMS-AN-2010-279, 2011.

[76] S.Chatrchyan, et al. Measurement of W� and Z� production in pp collisions atps = 7 TeV.

Phys. Lett. B, 701:535, 2011.

[77] CMS Collaboration. Study of V + � final states. CMS Physics Analysis Summary, CMS-PAS-EWK-10-008, 2011.

[78] J. Veverka. Photon Energy Scale with FSR Photons: Closure Test of Baseline Energy Scalefrom Z ! µµ�. CMS V� Meeting, 28 October 2011. https://indico.cern.ch/event/160813.

[79] J. Veverka. Photon energy scale: Update on Closure Test of Baseline Energy Scale fromZ ! µµ�. CMS V� Meeting, 11 November 2011. https://indico.cern.ch/event/162607.

[80] J. Veverka. FSR Z ! µµ� energy scale/resolution measurement: Introducing PHOS-PHOR Fit. CMS Ecal DPG/Egamma POG meeting on Clustering, 6 February 2012.https://indico.cern.ch/event/176399.

[81] J. Veverka. PHOSPHOR Fit Update. CMS DPG/PH Egamma Meeting, 22 March 2012.https://indico.cern.ch/event/183123.

[82] J. Veverka. Photon energy scale and resolution with Z ! µµ� using the PHOSPHOR fit. CMSEgamma Identification Meeting, 13 April 2012. https://indico.cern.ch/event/186547.

[83] J. Veverka, Y. Yang. Photon performance measurements with Z ! µµ� Events Selected at 7TeV. CMS Analysis Note, CMS-AN-2012-043, 2012.

vii

[84] A. Askew, et. al. Study of W� and Z� production at CMS withps = 7TeV . CMS Analysis

Note, CMS-AN-2011-251, 2012.

[85] CMS Collaboration. Study of V + � final states. CMS Physics Analysis Summary, CMS-PAS-EWK-11-009, 2012.

[86] ”Fast Detectors and Electronics for Future Experiments” G. Varner, CSS2013, Snowmass onthe Mississippi, July 2013, http://goo.gl/rXhi1G

[87] Large-Area Picosecond Photo-Detectros Project, http://psec.uchicago.edu

[88] SUSY 2013, Trieste, ”Searches for SUSY with the CMS experiment”http://susy2013.ictp.it/lecturenotes/03 Wednesday/Richman.pdf

[89] LHC CERN-PH Seminar, September 3, 2013, Latest results on searches for Supersymmetryfrom CMS

[90] A. Apreysan et al. “2011 Razor Trigger Suite” AN-2011/219

[91] T. Orimoto, Y. Ma, C. Henderson, and S. Simon, ”Search for Randall-Sundrum Gravitons inthe Diphoton Channel in pp Collisions at

p(s) = 7 TeV, CMS PAS EXO-10-019, 2011

[92] CMS Collaboration,“Search for Signatures of Extra Dimensions in the Diphoton Mass Spec-trum at the Large Hadron Collider”, Phys. Rev. Lett. 108, 111801 (2012)

[93] M. Gataullin et al., “Intercalibration of the CMS Barrel Electromagnetic Calorimeter UsingNeutral Pion Decays,” CMS Detector Note 2007/013, 2007V. Litvin, H. Newman, and S. Shevchenko, “ECAL Barrel Calibration at LHC Startup with⌘ ! �� Decays”, CMS Internal Note 2004/021, 2004

[94] M. Gataullin et al., “Online Selection of ⇡0 ! �� Decays and Performance of the ⇡0 Inter-calibration Method at the LHC Startup”, CMS Detector Note 2009/006, 2009M. Gataullin et al., “Online Selection of ⌘0 ! �� Decays and Performance of the ⌘0 Intercali-bration Method at the LHC Startup”, CMS Detector Note 2009/007, 2009M. Gataullin et al., “Intercalibration of the CMS Barrel Electromagnetic Calorimeter UsingNeutral Pion Decays from 2006 Test Beams”, CMS Detector Note 2007/007, 2007

[95] Y. Yang, A. Bornheim, M. Gataullin, CMS AN-2011/507, “Calibration of the CMS ECALwith ⇡0/⌘ Decays with 2011 Data”, 2011M. Gataullin et al., “⇡0 Calibration Trigger Performance and InterCalibration of the CMSECAL with 7 TeV Data”, CMS Analysis Note 2010/216, 2010M. Gataullin, R. Paramatti, et al., “Calibration of the CMS ECAL at 7 TeV”, CMS PAS-EGM-10-003, 2010.

[96] A. Bornheim et al., “Performance of the CMS ECAL”, CMS PAS-EGM-11-001, 2011.

[97] X.D. Qu et al., Radiation Induced Color Centers and Light Monitoring for Lead TungstateCrystals, IEEE Trans. Nucl. Sci. NS-47 (2000) 1741.

[98] L.Y. Zhang, K.J. Zhu and R.-Y. Zhu, Monitoring Light Source for CMS Lead Tungstate CrystalCalorimeter at LHC, IEEE Trans. Nucl. Sci. NS-48 (2001) 372.

viii

[99] L.Y. Zhang, K.J. Zhu, D. Bailleux, A. Bornheim and R.-Y. Zhu, Implementation of a SoftwareFeedback Control for the CMS Monitoring Lasers, IEEE Trans. Nucl. Sci. NS-55 (2008) 637–643.

[100] L.Y. Zhang et al., Installation of the ECAL Monitoring Light Source, CMS Internal Note2001/008.

[101] D. Bailleux et al., ECAL Monitoring Light Source at H4, CMS Internal Note 2003/045.

[102] R.-Y. Zhu, http://www.hep.caltech.edu/⇠zhu/talks/ryz 101207 laser.pdf, Monitoring LaserUpgrade, talk given at the CMS ECAL Plenary Meeting at CERN, December 7, 2010.

[103] R.-Y. Zhu, http://www.hep.caltech.edu/⇠zhu/talks/ryz 120228 laser.pdf, Photonics DP2-447 Laser, talk given at the CMS ECAL General Meeting at CERN, February 28, 2012.

[104] R.-Y. Zhu, http://www.hep.caltech.edu/⇠zhu/talks/ryz 101209 pwo.pdf, �-Ray InducedLight Loss in PWO Crystals, talk given at the CMS Forward Calorimetry Task Force Meetingat CERN, December 9, 2010.

[105] R.H. Mao, L.Y. Zhang, R.-Y. Zhu, Quality of Mass Produced Lead Tungstate Crystals, IEEETrans. Nucl. Sci. NS-51 (2004) 1777 and Nucl. Instr. and Meth. A537 (2005) 406.

[106] CMS Collaboration, Technical Proposal for the Upgrade of the CMS Detector through 2020,CMS U1 TDR 2011/01/14.

[107] Liyuan Zhang, Rihua Mao and R.-Y. Zhu, Fast Neutron Induced Nuclear Counter E↵ect inHamamatsu Silicon PIN Diodes and APDs, IEEE Trans. Nucl. Sci. NS-58 (2011) 3249–1256.

[108] J.M. Chen, L.Y. Zhang and R.-Y. Zhu, Large Size LYSO Crystals for Future High EnergyPhysics Experiments, IEEE Trans. Nucl. Sci. NS-52 (2005) 3133–3140.

[109] J.M. Chen, L.Y. Zhang and R.-Y. Zhu, Large Size LSO and LYSO Crystal Scintillators forFuture High Energy Physics Experiments, IEEE Trans. Nucl. Sci. NS-54 (2007) 718–724 andNucl. Instr. and Meth. A572 (2007) 218–224.

[110] J.M. Chen, R.H. Mao, L.Y. Zhang and R.-Y. Zhu, Gamma-ray Induced Radiation Damage inLarge Size LSO and LYSO Crystal Samples, IEEE Trans. Nucl. Sci. NS-54 (2007) 1319–1326.

[111] R.H. Mao, L.Y. Zhang and R.-Y. Zhu, Gamma Ray Induced Radiation Damage in PWO andLSO/LYSO Crystals, Paper N32-5 in NSS 2009 Conference Record (2009) 2045–2049.

[112] R.H. Mao, L.Y. Zhang and R.-Y. Zhu, E↵ect of Neutron Irradiations in Various CrystalSamples of Large Size for Future Crystal Calorimeter, Paper N32-4 in NSS 2009 ConferenceRecord (2009) 2041–2044.

[113] R.-Y. Zhu, http://indico.cern.ch/getFile.py/access?sessionId=0&resId=4&materialId=0&confId=97272, Forward Calorimetry Ideas, talk given at the CMS Forward Calorimetry TaskForce Meeting at CERN, June 17, 2010.

[114] R.H. Mao, L.Y. Zhang and R.-Y. Zhu, Optical and Scintillation Properties of Inorganic Scin-tillators in High Energy Physics, IEEE Trans. Nucl. Sci. NS-55 (2008) 2425–2431.

ix

[115] R.-Y. Zhu, Crystal Calorimeters in the Next Decade, in Proceedings of XIII InternationalConference on Calorimetry in Particle Physics, Ed. M. Fraternali et al., IOP Conference SeriesVolume 160 (2009) 012017.

[116] R.H. Mao, L.Y. Zhang and R.-Y. Zhu, Quality of a 28 cm Long LYSO Crystal and Progresson Optical and Scintillation Properties, Paper N38-2 in IEEE NSS 2010 Conference Record(2010).

[117] Joe Lykken Maria Spiropulu Roberto Vega-Morales Yi Chen, Emanuele DiMarco and Si Xie.Directly Extracting the ZZ Couplings of the Higgs Boson in the Golden Channel.

[118] Joe Lykken Maria Spiropulu Roberto Vega-Morales Yi Chen, Emanuele DiMarco and Si Xie.Directly Extracting the ZZ Couplings of the Higgs Boson in the Golden Channel: TechnicalDetails.

[119] Shashank Shalgar Yi Chen, Kunal Kumar and Roberto Vega-Morales. Re-Scrutinizing theHiggs Signal and Background in the Golden Channel.

[120] Measurement of the production and decay of a higgs boson in the four-lepton final state.(CMS-Paper-HIG-13-003), 2013.

[121] Properties of the higgs-like boson in the decay h ! zz ! 4` in pp collisions atps = 7 and 8

tev. (CMS-PAS-HIG-13-003), 2013.

[122] Search for the standard model higgs boson decaying to ww in leptonic final states atps = 7

and 8 tev with the cms experiment. (CMS-PAS-HIG-13-003), 2013.

[123] Search for the standard model higgs boson decaying to ww in leptonic final states atps = 7

and 8 tev with the cms experiment. (CMS-Paper-HIG-13-023 under publication), 2013.

[124] Serguei Chatrchyan et al. Study of the Mass and Spin-Parity of the Higgs Boson Candidatevia Its Decays to Z Boson Pairs. Phys. Rev. Lett., 110:081803, 2013.

[125] E. Di Marco et al. Measurement of the production and decay of a higgs boson in the four-lepton final state. CMS Analysis Note, 2013/108, 2013.

[126] Chen Y. et al. Higgs boson decaying to ww in the leptonic final state measurement usingrazor variables. CMS Analysis Note, 2013/002, 2013.

[127] J. Brochero et al. Higgs boson decaying to ww in the leptonic final state using 2011 and 2012data. CMS Note, 2013.

[128] Measurement of the higgs boson pair production cross section at 14 tev in the decay channelto two photons and two b-jets. Technical Report CMS-PAS-FTR-13-001, CERN, Geneva, 2013.

[129] Measurement of the higgs pair production cross section at 14 tev in the decay channel to twophotons and two b-jets. Technical Report CMS-AN-13-050, CERN, Geneva, 2013.

[130] CMS Collaboration. Search for supersymmetry with taus using the razor variables. CMSPAS, 2012.

[131] CMS Collaboration. Search for supersymmetry with photons using the razor variables”,journal =.

x

[132] S. Chatrchyan et al. Inclusive search for supersymmetry using razor variables in pp collisionsat

ps=7 TeV. Phys. Rev. Lett., 111:081802, Aug 2013.

[133] J. Duarte et al. Inclusive razor search for susy atps = 8 tev with 19.3fb�1. CMS Note, 2013.

[134] CMS Collaboration. Search for supersymmetry with razor variables in events with b-jets at8 TeV. CMS PAS, 2013.

[135] C. Rogan. Kinematics for new dynamics at the lhc. 2010. CALT-68-2790.

[136] Serguei Chatrchyan et al. Inclusive search for squarks and gluinos in pp collisions at sqrt(s)= 7 TeV. Phys. Rev. D., 85, 2012.

[137] Johan Alwall, Philip Schuster, and Natalia Toro. Simplified Models for a First Characteriza-tion of New Physics at the LHC. Phys. Rev., D79:075020, 2009.

[138] Johan Alwall, My Phuong Le, Mariangela Lisanti, and Jay G. Wacker. Searching for gluinosat the Tevatron and beyond. Int. J. Mod. Phys., A23:4637–4646, 2008.

[139] Daniele Alves, Nima Arkani-Hamed, Sanjay Arora, Yang Bai, Matthew Baumgart, et al.Simplified Models for LHC New Physics Searches. 2011.

[140] Zhao-Huan Yu, Xiao-Jun Bi, Qi-Shu Yan, and Peng-Fei Yin. Detecting light stop pairs incoannihilation scenarios at the LHC. 2012.

[141] Karol Krizka, Abhishek Kumar, and David E. Morrissey. Very Light Scalar Top Quarks atthe LHC. 2012.

[142] Antonio Delgado, Gian F. Giudice, Gino Isidori, Maurizio Pierini, and Alessandro Strumia.The light stop window. 2012.

[143] Hyun Min Lee, Veronica Sanz, and Michael Trott. Hitting sbottom in natural SUSY. JHEP,1205:139, 2012.

[144] Ezequiel Alvarez and Yang Bai. Reach the Bottom Line of the Sbottom Search. JHEP,1208:003, 2012.

[145] J. Duarte et al. Search for direct stop production at 8 tev with the razor. CMS Note, 2013.

[146] CMS Collaboration. Search for direct stop production at tps = 8 tev with the razor. CMS

PAS, 2013.

[147] A.Apresyan, M.Spiropulu, K.Swanson, “HCAL Noise Rate Stability Using Pulse-Shape Fit-Based Filters”, CMS Analysis Note AN-2011/395

[148] A. Apresyan, A. Bornheim, J. Olsson, M. Spiropulu, “Impact of anomalous signals in CMSElectromagnetic calorimeter on jet reconstruction”, CMS Analysis Note AN-2011/481

[149] CMS Collaboration, “Missing transverse energy performance of the CMS detector”, 2011JINST 6 P09001

[150] CMS Collaboration, “MET Performance in 2011 CMS Data”, CMS Detector PerformanceNote

xi

[151] A. Apresyan, S.Bouma, M. Spiropulu, “Optimization of JetMET Data Quality Monitoring”,CMS Analysis Note AN-2011/521

[152] A. Apresyan, S.Bouma, A.Mott, M. Spiropulu, “Studies of b-tagging at High Level Triggerwith combinatorial and iterative tracking”, CMS Analysis Note AN-2011/520

[153] A. Apresyan, “Identification and mitigation of anomalous signals in CMS HCAL” CMS Con-ference Report CMS-CR-2012/238, http://cds.cern.ch/record/1479437/ 2012.

[154] SuperComputing 2011, http://supercomputing.caltech.edu

[155] A PRL and PRD under editing with the razor 2011 results (to be submitted 2012).

[156] CMS AN-2012/163, ”Measurement of the production cross section ratio of WW to Z at 7TeV”

[157] CMS AN-2012/156, ”5/fb Reload: Search for Pair Production of Third-Generation ScalarLeptoquarks Using Events Produced in pp Collisions at sqrt= 7 TeV Containing b-jets andMissing Transverse Energy”

[158] CMS AN-2012/144, ”HCAL Noise WG Summary: on noise filters for 2012 analyses”

[159] CMS AN-2012/121, ”Optimization of Muon Isolation to reduce W+Jets Background andmitigate Pile-up e↵ects in Di-Lepton final states”

[160] CMS AN-2012/091, ”Search for massive new particles in final states with boosted objectsusing the Razor variables”

[161] CMS AN-2012/086, ”Study of associated Higgs (VH) Production with H to W+W� andhadronic V decay with 4.9 fb-1 at 7 TeV”

[162] CMS AN-2012/071, ”Search for the Higgs Boson in H ! W+W� ! 2l2⌫ in pp Collisions ats=7 TeV with razor variables”

[163] CMS AN-2012/036, ”WW cross section measurement in the Fully Leptonic Final State with4.63 fb-1 at 7 TeV”

[164] CMS AN-2011/516, ”An inclusive search for the decays of a new high-mass state with METin multijet events using the Razor variables”

[165] CMS AN-2011/495, ”Razor inclusive search for pair-produced heavy particles at sqrt(s) = 7TeV with ⇠ 4.4fb�1”

[166] CMS AN-2011/458, ”Search for supersymmetry in final states with b-jets using the razorvariables”

[167] CMS AN-2011/457, ”Search for supersymmetry in final states with photons using the razorvariables”

[168] CMS DN-2011/008, ”Studies with the HCAL 2009 Test Beam data”

[169] CMS AN-2011/335, Search for Pair Production of Third-Generation Scalar Leptoquarks Us-ing Events Produced in pp Collisions at s= 7 TeV Containing b-jets and Missing TransverseEnergy

xii

[170] CMS AN-2011/233, Razor inclusive search for pair-produced heavy particles at sqrt(s) = 7TeV

[171] CMS AN-2011/226, Search for Randall-Sundrum Gravitons Decaying into a Jet plus MissingET at CMS

[172] “Inclusive search for squarks and gluinos at sqrt(s) = 7 TEV”, To be submitted, (CMS-PAS-SUS-10-009), 2011, cdsweb hyper link

[173] “Rates of jets produced in association with W and Z bosons”, To be submitted, (CMS-PAS-EWK-10-012), 2011, cdsweb hyper link

[174] “Higgs boson look-alikes at the LHC” A. De Rujula, J. Lykken, M. Pierini, C. Rogan, andM. Spiropulu Phys. Rev. D 82, 013003 (2010). PRD hyperlink

[175] “High-energy physics. Proceedings, 5th CERN Latin- American School”, Recinto Quirama,Colombia, March 15-28, 2009,arXiv:1010.5976, C. Grojean and M. Spiropulu

[176] C. Grojean and M. Spiropulu, “High-energy physics. Proceedings, 17th European School, ES-HEP 2009”, Bautzen, Germany, June 14-27, 2009, arXiv:1012.4643 C. Grojean and M. Spiropulu

[177] HCAL performance from first collisions data. CMS Detector Performance Summary, DPS-2010/025, 2010 (Includes ICHEP filters).

[178] “Calorimetry task force report”, Technical Report CMS-NOTE-2010-007. CERN-CMS-NOTE-2010-007, CERN, Geneva, Mar 2010, cdsweb record

[179] CMS Collaboration, “On measuring missing transverse energy with the CMS detector in ppcollisions at

ps =7 TeV”, CMS PAPER JME-10-009, (2010). to be submitted to JINST

[180] “HCAL Barrel and Endcap fit-based noise discriminants”, DN-2011-005, 2011

[181] “HCAL Noise Working Group Summary for CMS 2010 analyses” DN-2011/006

[182] “Inclusive search for pair-produced heavy particles at 7 TeV”, CMS Analysis Note 2010/288

[183] “Search for SUSY Particles in Ditau Events using MR in CMS 7 TeV data”, CMS AnalysisNote 2010/287,

[184] “Interpreting CMS data in the phenomenological MSSM”, CMS Analysis Note 2011/040

[185] VECBOS working group contibuting Analysis Notes (2010) to V+jets CMS Analysis Note2010/413, and CMS-PAS-EWK-10-012 : CMS Analysis Note 2010/426, CMS Analysis Note2010/342, CMS Analysis Note 2010/424, CMS Analysis Note 2010/425, CMS Analysis Note2010/425

[186] “Measurement of Berends-Giele Scaling and Z+jets/W+jets cross-section ratio with muonfinal states using full Particle-Flow analysis” CMS Analysis Note 2010/384

[187] “Measurement of the Associated Production of Vector Bosons and Jets in proton protoncollisions at 7 TeV”, CMS Analysis Note 2010/413

[188] “Subtracting the background from top quark production in the W + jets measurements”CMS Analysis Note 2010/461

xiii

[189] “Trigger Studies for the SUSY and Exotica Physics Analysis Groups”, CMS Analysis Note2010/032

[190] “Uncorrected Calorimeter MET decomposition using the CMS tracker at the low energy LHCcommissioning runs” CMS Analysis Note 2010/025

[191] “Missing Transverse Energy and decomposition using the event thrust axis atps = 7 TeV”,

CMS Analysis Note 2010/180

[192] “Commissioning of Uncorrected Calorimeter Missing Transverse Energy in Zero Bias andMinimum Bias Events at 900 GeV 2360 GeV runs”, CMS Analysis Note 2010/029

[193] “Measurement of kinematic properties of top and W+jets processes in the muon+3 jetschannel using sPlots”, CMS Analysis Note 2010/251

[194] S. Sekmen, S. Kraml, J. Lykken, F. Moortgat, S. Padhi, L. Pape, M. Pierini and H. B. Prosperet al., “Interpreting LHC SUSY searches in the phenomenological MSSM,” JHEP 1202, 075(2012) [arXiv:1109.5119 [hep-ph]].

[195] M. Pierini, H. Prosper, S. Sekmen and M. Spiropulu, “Model Inference with Reference Priors,”arXiv:1107.2877 [hep-ph].

[196] H. Newman, “A New Generation of Networks and Computing Models for High Energy Physicsin the LHC Era”, J. Phys. Conf. Ser. 331 (2011) 012004; Proceedings of the Int’l Conf. onComputing for HEP, Taipei, 2010

[197] R. Voicu et al., “The Dynamics of Network Topology”, Phys. Conf. Ser. 331 (2011) 052033;Proceedings of the Int’l Conf. on Computing for HEP, Taipei, 2010

[198] I. Legrand et al., “Workflow Management in Large Distributed Systems”, Phys. Conf. Ser.331 (2011) 072022; Proceedings of the Int’l Conf. on Computing for HEP, Taipei, 2010

[199] Z. Maxa, B. Ahmed, D. Kcira, I. Legrand, A. Mughal, M. Thomas and R. Voicu, “Poweringphysics data transfers with FDT,” J. Phys. Conf. Ser. 331, 052014 (2011).

[200] J. Adelman-McCarthy, O. Gutsche, J. D. Haas, H. B. Prosper, V. Dutta, G. Gomez-Ceballos,K. Hahn and M. Klute et al., “CMS distributed computing workflow experience,” J. Phys. Conf.Ser. 331, 072019 (2011).

[201] Yong Yang, Marat Gataullin, Adolf Bornheim, “Calibration of the CMS ECAL with ⇡0 ! ��and ⌘ ! �� decays” CMS AN-2011/507Yong Yang for the CMS Collaboration, “Commissioning, Performance and Calibration of Crys-tals of the Electromagnetic Calorimeter of CMS”, CMS CR-2010/270Marat Gataullin, “Intercalibration of the CMS Electromagnetic Calorimeter Using ⇡0 ! ��Decays from 2006 Test Beams”, CMS DN-2007/07Yong Yang,“Online Selection of ⇡0 ! �� Decays and Performance of the ⇡0 InterCalibrationMethod at the LHC Startup”, CMS DN-2009/006

[202] Bornheim, A et al., “Laser monitoring system for the CMS lead tungstate crystalcalorimeter”,CMS-NOTE-2007-028.- Geneva : CERN, 2007 - 41 pCMS Collaboration,“2012 ECAL detector performance plots”, CMS DP-2013/007,

xiv

[203] Jan Veverka, Yong Yang, “Photon performance measurements with Z ! µ+µ�� EventsSelected at 7 TeV”, CMS AN-2012/043

[204] Yong Yang, “Search for a Standard Model Higgs Boson Decaying to Two Photons in CMSat the LHC”, Caltech Thesis, November 2012

[205] Lisa Randall, Raman Sundrum, “A Large Mass Hierarchy from a Small Extra Dimension”,10.1103/PhysRevLett.83.3370

[206] J.C. Collins, D. E. Soper, Phys. Rev. D 16, 2219 (1977)

[207] Yi Chen, Nhan Tran, Roberto Vega-Morales, “Scrutinizing the Higgs Signal and Backgroundin the 2e2µ Golden Channel”, 10.1007/JHEP01(2013)182

[208] Christopher Rogan, “Searches for New Symmetries in pp Collisions with the Razor KinematicVariables at

ps = 7 TeV”, Caltech Thesis, February 2013

[209] A. Bornheim, K.H. Chen, L. Fernanda Chaparro, Z. Demiragli, M. Dordevic, A. Ferapontov,S. Ganjour, K. Hahn, A. Hess, M. Kadastik, C.M. Kuo, A. Kyriakis, Y.J. Lei, S.W. Li, R.S. Lu,L. Lusito, C. Andres Carrillo Montoya, A. Mott, A. Felipe Osorio Oliveros, C. Paus, C. Pena,B. Pollack, L. Rebane, V. Rekovic, J. Carlos Sanabria, K. Singh, F. Stoeckli, S. Stoynev, M.Velasco, J. Veverka, R. Volpe, S. Xie, “Search for the Higgs boson in Z+gamma decays”, CMSAN-12-387

[210] Cristian Pena, Adi Bornheim, Alex Mott, Jan Veverka, Si Xie, Yong Yang, “Measurement ofPhoton Energy Scale and Resolution with Z0 ! µ+µ�� decays in 2011 and 2012 Data”, CMSAN-2012/382

[211] CMS Collaboration, “Search for a standard-model-like Higgs boson with a mass of up to 1TeV at the LHC”, CMS PAS-HIG-12-034,CERN-PH-EP/2013-050, April 2013

[212] CMS Collaboration, “Combination of standard model Higgs boson searches and measure-ments of the properties of the new boson with a mass near 125 GeV”, CMS-PAS-HIG-12-045

[213] Christoph Englert, Emanuale Re, Michael Spannowsky, “Triplet Higgs Collider Phenomenol-ogy after LHC”, arXiv:1302.6505H. Georgi and M. Machacek, Nucl. Phys. B 262(1985) 463.M. S. Chanowitz and M. Golden, Phys. Lett. B 165 (1985) 105

[214] CMS Collaboration, “A search for the decays of a new heavy particle in multijet events withthe razor variables at CMS in pp collisions at

ps = 7 TeV”, CMS-PAS-SUS-12-009

[215] CMS Collaboration, “Search for narrow resonances in dilepton mass spectra in pp collisionsat

ps = 7 TeV”, Phys. Lett. B 714 (2012) 158 DOI:10.1016/j.physletb.2012.06.051, CMS-EXO-

11-019; CERN-PH-EP-2012-157

[216] CMS Collaboration, “Search for third-generation leptoquarks and scalar bottom quarks inpp collisions at

ps = 7 TeV”, arXiv:1210.5627; CMS-EXO-11-030; CERN-PH-EP-2012-297.-

Geneva : CERN, 2012 - 39 p. - Published in : J. High Energy Phys. 12 (2012) 055

xv

Appendix 1.1.2 Other References

[217] D. Alves et al. [LHC New Physics Working Group Collaboration], “Simplified Models forLHC New Physics Searches,” arXiv:1105.2838 [hep-ph].

[218] J. Alwall, P. Schuster and N. Toro, “Simplified Models for a First Characterization of NewPhysics at the LHC,” Phys. Rev. D 79, 075020 (2009) [arXiv:0810.3921 [hep-ph]].

[219] J. Alwall, M. -P. Le, M. Lisanti and J. G. Wacker, “Model-Independent Jets plus MissingEnergy Searches,” Phys. Rev. D 79, 015005 (2009) [arXiv:0809.3264 [hep-ph]].

[220] Comparison of the Fast Simulation of CMS with the first LHC data, 2010, CMS-DP-2010-039.

[221] T. Sjostrand, S. Mrenna and P. Z. Skands, “PYTHIA 6.4 Physics and Manual,” JHEP 0605,026 (2006) [hep-ph/0603175].

[222] W. Beenakker, R. Hopker and M. Spira, “PROSPINO: A Program for the production ofsupersymmetric particles in next-to-leading order QCD,” hep-ph/9611232.

[223] B. Clerbaux et al., “Search for High-Mass Resonances Decaying to Electron Pairs in the CMSExperiment with 4.7 fb�1 of data.” CMS AN-2011/444

[224] L. Randall and R. Sundrum, “A Large Mass Hierarchy from a Small Extra Dimension”, Phys.Rev. Lett. (1999) 3370-3373

[225] H. Davoudiasl, J. L. Hewett, and T. G. Rizzo, “Experimental Probes of Localized Gravity:On and o↵ the wall” Phys. Rev. D63:075004, 2001.

[226] Pati, Jogesh C. and Salam, Abdus, Lepton number as the fourth color, Phys. Rev. D 10,275289 (1974).

[227] B. Schrempp and F. Schrempp, Light leptoquarks, Phys. Lett. B, 153:101,1985.

[228] S. Dimopoulos and L. Susskind, Mass without scalars, Nucl. Phys. B155 (1979) 237-252

[229] S. Dimopoulos, Technicoloured signatures, Nucl. Phys. B168 (1980) 69-62

[230] E. Farhi and L. Susskind, Technicolour, Phys. Rept. 74, 277 (1981)

[231] ”J.L. Hewett and T. G. Rizzo, Low-energy phenomenology of superstring-inspired E6 models,Phys. Rev. D 61 (2000) 016007

[232] P. Lecomte, D. Luckey, F. Nessi-Tedaldi and F. Pauss, “High Energy Proton Induced DamageStudy of Scintillation Light Output from PWO Calorimeter Crystals”, Nucl. Instrum. Methods.A564 (2006) 164–168.

[233] F. Nessi-Tedaldi, G. Dissertori, P. Lecomte, D. Luckey and F. Pauss, Studies of CeriumFluoride, LYSO and Lead Tungstate Crystals Exposed to High Hadron Fluences, Paper N32-3in NSS 2009 Conference Record (2009).

[234] A. Bornheim, Calorimeters for precision timing measurements in high energy physics, Journalof Physics: Conference Series (2014)

xvi

[235] A. Ronzhina, S. Losa, E. Ramberga, M. Spiropulu, A. Apresyan, S. Xie, H. Kim, A.Zatserklyaniy, Development of a new fast shower maximum detector based on microchannelplates photomultipliers (MCP-PMT) as an active element, NIM A 759 (2014) 65-73, (2014),http://dx.doi.org/10.1016/j.nima.2014.05.039

[236] CMS Collaboration, “Technical proposal for the Phase II upgrade of the Compact MuonSolenoid”, (2014)

Appendix 1.1.3 Theses

[237] Yousi Ma (Defended May 7, 2012):Search for Signatures of Extra Dimensions in the Diphoton Mass Spectrum with the CMSDetectorhttp://resolver.caltech.edu/CaltechTHESIS:05182012-101542629

[238] Yong Yang (Defended November 7, 2012)Search for a Standard Model Higgs Boson Decaying to Two Photons in CMS at the LHChttp://resolver.caltech.edu/CaltechTHESIS:12192012-133848927

[239] Chris Rogan (Defended February 12, 2013)Search for New Symmetries in pp Collisions with the Razor Kinematic Variables at

ps = 7 TeV

http://resolver.caltech.edu/CaltechTHESIS:05072013-174540453

[240] Vladlen Timciuc (Defended May 10, 2013)Search for Heavy Neutral Gauge Bosons in the Dielectron Channel with the CMS Detector atthe LHC http://resolver.caltech.edu/CaltechTHESIS:05312013-220518835

[241] Jan Veverka (Defended May 15, 2013)Associated Z� Production Measurement with the CMS Detector http://resolver.caltech.edu/CaltechTHESIS:05302013-043445308

[242] Valere Lambert (Defended May 27, 2014)Multi-model inference ranking and applications to physics at the Large Hadron Collider. Seniorthesis (Major)http://resolver.caltech.edu/CaltechTHESIS:06122014-143656852