Early Physics Prospects at CMSJeffrey Berryhill/FNAL CMS CenterBeyond the Standard Model: from the Tevatron to the LHCSept. 17 2008

What happened September 10th?

CERN celebrates first complete proton beam circulation in LHC

Both beam lines sustained for minutes at a time

CMS, ATLAS, LHCb and ALICE all report beam halo eventsFermilab/USCMS celebrates with all-nightpajama party

CMS beam halo observed in the remote operations center

Worldwide press and live BBC coverage

Possible 2008 Run Plan

Establish collisions at 900 GeV this monthEstablish 10 TeV collisions within 30 days~30 days of physics delivering ~10 pb-1 to detectorsCoasting for one month in most advanced mode (1% of design lumi) delivers ~40 pb-1Retrain the quenching dipoles during winter shutdown to allow 14 TeV collisions in 2009

Mid-Oct.

10 TeV vs. 14 TeV

10 TeV operations is a temporary measure to minimize dipole quenches seen at 14 TeV(limited to a specific manufacturer).

Dipoles to be re-trained to restore response forgotten from surface tests, in time for 2009 run

Running at 10 TeV instead of 14 TeVdegrades cross sections of processes far from the LHC kinematic limit by about a factor 2

Discovery potential is largely maintained even with a (unanticipated)prolonged running period at 10 TeV

21014

2009 Run Plan and Beyond

BCNo beamBeam2009Commission beams for 14 TeV collisionsPlan for 150 days of pp physics running, w/efficiency for physics 40%

Phase B: 1-10% of design lumi, ~few 100 pb-1Phase C: 10-20% of design lumi, minimum bunch spacing, ~few fb-1

>=2010: attain 1034 design lumi, collect up to 60 fb-1/year, collect 300 fb-1SuperLHC: IR+detector upgrades, 1035 lumi, 600 fb-1/year, collect 3 ab-1

Train to7TeVMachine checkoutBeam Setup75ns ops25ns ops IShutdown

CMS Status

All subdetectors have been installed and have

recorded cosmic ray data with central trigger/DAQ

Growing pains:ECAL endcaps all made it in at the last minute, however trigger

electronics there is arriving late (Nov.) for 2008 run* *No electron or photon trigger for |eta| > 1.5BUT readout is operational for otherwise-accepted events 3.8T solenoid cavern-tested

only 10 days ago, understanding fringe field and mechanical(!)impact on rest of CMS

Troubleshooting front-end

electronics noise

CMS Physics Program

Characterized roughly by epochs of log10(Integrated luminosity):

2008:0-1 pb-1 Channel-level detector calibration & alignment. Measurements of minimum bias pp and low PT leptons and jets. Modest W and Z signals possibly observable.

2008?2009?1-10 pb-1 Commissioning of high PT electrons, muons, and jets. Thousands of Z to dileptons, 10X more W to leptons Plentiful high-PT jet sample, small top signal possible 2009:10-100 pb-1 Re-discovery of the Standard Model. Precision W/Z/top cross sections, diboson production + discovery potential in some channels (jets, CMSSM SUSY, TeV Z). b-jet commissioning. Usable missing ET resolution and jet energy scale.

CMS Physics Program

2009?2010? 0.1-1 fb-1 Gold rush phase begins: usable calibration and commissioning for all high PT physics objects (taus). Tevatron sensitivity usurped over a broad range of channels. SM Higgs evidence from 160 to 400 GeV. 2010 and beyond1-10 fb-1 SM Higgs discovery, high-mass BSM discovery

10-100 fb-1 precision BSM, or evidence for stingier scenarios (VBF) It is a prerequisite to almost any search or discovery to successfully complete the 1/10/100 pb-1 commissioning and SM re-discovery program

CMS Physics Program

0-1 pb-1 calibration, alignment. Measurements of minimum bias pp and low PT leptons and jets. Very low lumi, very open trigger.

In-situ ECAL and HCAL response calibration (phi symmetry et al.)Tracking/muon chamber efficiency of muons w/ J/y and UpsilonUnderlying event measurement at 10-14 TeVLow PT electron, photon, and conversion studiesFirst look at jets Track multiplicity in minbias @ 1pb-1

p0 calibration of ECAL

CMS Physics Program

Z ee signal @10 pb-1W mn signal @10 pb-11-10 pb-1 Commissioning of high PT electrons, muons, and jets. thousands of electron and muon pairs from Zs essential for optimizing lepton triggering, reconstruction, and IDUsability of missing ET diagnosed with large (10^5) W sample

EWK xsecs and ratios are first precision tests of CMS analysis capability

CMS Physics Program

10-100 pb-1 Re-discovery of the Standard Model. Precision W/Z/top cross sections, diboson production + discovery potential in some channels (jets, CMSSM SUSY, TeV Z). Usable missing ET resolution and jet energy scale. Multi-TeV q/g compositeness sensitivity once JES is knownTop dilepton signal @100 pb-1 with commissioned MET, btagging, JES. Top lepton+jets can ultimately be a calibration sample for them!

CMS Discovery Phase

Light SM Higgs discovery @ 10 fb-1MSSM gluino/squark 5s discovery @ 1fb-1M(1/2) < 650 GeV, M(0) < 1.5 TeV

LM1 discovery with < 10 pb-1(if you understand jets and MET but that will take ~10-100 pb-1)Heavy SM Higgs discovery @ 5 fb-1

CMS vs. ATLAS

ATLAS has better: HAD calorimetry,~6 months head start in commissioning

CMS has better:ECAL E resolutionTrack/muon P res.

CMS vs. CDF/D0

Advantages for CMS:

ECAL granularity and resolution is excellent

Tracking, ECAL and muon acceptance lead to good lepton trigger and ID out to eta of 2.5

3.8T magnet plus 200 m^2 of silicon lead to better IP and momentum resolution

Muons are everywhere redundantly triggered and tracked with RPCs

CMS vs. CDF/D0

BUTEven at 1% design lumi, CMS trigger is much more selective/less efficient. No inner tracking in the low-level trigger (bad for b,t).

The high mass tracker causes electron, photons, and pions to shower!

S/B often worse at 14 TeV: signal xsecs are 10X but tt, bb, multijet, and V+jet background xsecs are typically >10X

Biggest Tevatron edge by far is detector and analysis experience,

they will have better sensitivity per/event produced, so they will have unique results for medium x searches (read: Higgs) some time after the crossover point of ~100pb-1@LHC

Once the LHC enters the fb-1 epoch, brute force wins the day.and the experience gap will close in time as well

Caveats for BSM

Missing ET commissioning will be a rocky road as we

characterize and eliminate all the unsimulated instrumental backgrounds

Signatures resulting in only b or tau particles will be difficult to

trigger on. Needs an e, mu, photon or something else to improve level 1 efficiency.Lower ET and non-isolated object topologies will be prescaled away

as lumi grows D0 raw missing ET in Run IIRun IIV. Shary CALOR04Need to understand

MET from collisions (pileup)MET from LHC (halo)MET from CMS (noise)

Before MET for physics is usable

Caveats for BSM

Signatures somewhat out of time ( ~10ns) particles will have

triggering problems (25 ns bunch crossing timing requirements for the trigger, trigger rules prohibiting consecutive bunches to trigger, limited time sampling of readout)

Very non-prompt (many cm) or kinked track signatures may also

be difficult to distinguish from tracker conversions/interactions

Caveats for BSM

Non-Vanilla physics objects will require a good deal of foresight to detect (reconstruction software and triggering). Ask experimenters to get started now!

Even seemingly vanilla signatures may not survive trigger evolution to higher lumi. Talk to your experimenter friends often about the trigger menu.

Although on paper discovery should be instantaneous in some BSM scenarios, there will be a protracted period of debugging and commissioning through the first 100 pb-1 which must occur to make any discovery a sound one.

These are exciting times!

Backups

MET Plans:From 1023 to 1027 /(cm2sec) 14 TeVFrom Dan Green

L for 1 month run (106 sec)Integrated LTriggerProcessComments1023100 mb-1NoneI~ 50 mbInelasticnon-diffInput to tweak Pythia10241 b-1Setup JetInelasticnon-diffCalib in azimuth102510 b-1Jet(gg) ~ 90 b(ggg) ~ 6 bg+g -> g+gg+g -> g+g+gEstablish JJ cross section1026100 b-1Jetg+g -> g+gg+g -> g+g+gDijet balance for polar angle Establish MET10271 nb-1JetSetup Photon(q) ~ 20 nbg+g -> g+gg+g -> g+g+gq+g -> q+ Dijet masses start jet balanceJ+ calib

Rough Plan for TausEstablishing basic trigger functionality:Tuning initial L1 tau definition and veto bitsTau trigger efficiency measurement using offline electrons and jets:Trigger efficiency measurements without real taus:Measurement using offline electrons:Measurement with tight offline taus (fakes):Final validation will need clean tau samplesRe-measure efficiencies using clean Zmt(et) Use inclusive m(e) triggersEstablishing basic functionality:Offline efficiency measurement using high quality electrons:Basic understanding of conversion finding:Further progress requires clean tau samples:Measure other ID efficiencies, energy calibration etcUse Zmt(et) using inclusive m(e) triggerBottom Line: Taus will be the last object to commission

0-0.1 pb-11-10 pb-110-100 pb-1 ?100-500 pb-1 ?10-100 pb-1 ?100-500 pb-1 ?