quest for the higgs boson - tifrmazumdar/talks/dst_cms.pdf · 2012-08-31 · the higgs boson...

Discovery of the Higgs Boson and India

Kajari Mazumdar On behalf of India-CMS group

Tata Institute of Fundamental Research Mumbai.

[email protected]

http://www.tifr.res.in/~mazumdar

India at the LHC, DAE-DST meeting, INSA, Delhi August 29, 2012

Eternal question of mankind

High Energy Physics tries to answer these synergy with other fields to push back frontiers of knowledge!

It also brings in technological spin-offs, eg., world-wide-web.

What principles govern the energy, matter, space and time at the most elementary level?

AD

8/29/2012 2 Higgs discovery and India: K. Mazumdar

u

u d

What lies within?

The probe wavelength should be smaller than the distance scale to be probed

•To probe structure of an atom (10 -10 m) need energy probe, E = 10 keV (X-ray) • For probing nucleon structure (10 -15 m) E = 100 MeV (electron)

Electron-Volt=energy gained by an electron in a potential difference of 1 Volt.


Atom Proton

Big Bang

Radius of Earth

Radius of Galaxies

Earth to Sun

Universe

Super-Microscope

LHC

Hubble ALMA

VLT AMS

Dimensions in Physics

• For probing new territory of 10 -20 m we need energy ~10+13 eV = 10 TeV!

1 GeV ~ mass of a proton ~ mass of hydrogen atom = 109 electron-Volt 1 TeV = 103 GeV = 1012 eV 10 TeV ~ 0.2 micro Joule

1 electron Volt (eV)= 1.6*10-19 Joules

100 Watt bulb for one hour > 1MegaJ !


Cartoon of our Universe

Today 13.7 Billion Years

1028 cm

1. Quantum gravity era: t≈ 10-43 s 1032 K (1019 GeV, 10-34m)

3. Protons and neutrons formed: t ≈ 10-4 s, 1013 K (1 GeV, 10-16 m)

•4. Nuclei are formed t = 3 minutes, • 109 K (0.1 MeV, 10-12 m)

Energy =kT Length scale = hc/E

Big Bang

(30 K)

2. LHC 10-12 s, 1016 K (104 GeV, 10-20 m)


All behaviour of matter particles (fermions) can be explained in terms of few forces carried by exchange or carrier particles (bosons).

LHC

Present Wisdom

1) γ for electromagnetic interaction 2) W ±, Z for weak .. 3) 8 gluons for strong ..


BUT MATTER IN THE UNIVERSE IS NEUTRAL, because positive and negative charges cancel each other precisely. THEREFORE: Gravitation is the dominant force in the Universe.

Relative strength of gravitation, weak, electromagnetic, strong ~10 -40 : 10 -5 : 10 -2 : 1

Fundamental Forces


Elementary particles and their masses

• Everyday matter is made up of only up and down quarks, electron.

Matter:

the missing piece till now

• Though mass is a fundamental property of particles, we have lack of wisdom : we do not know the origin of the masses! How do we put everything together?


Five fold symmetry Radial symmetry Reflection/Bilateral symmetry

Dogma of Symmetry

Symmetry has practical uses too. (a) position of pivot in load balance (b) 2 eyes correct judgment of distance.


Highlights of 20th century physics

• Special relativity • General Relativity • Quantum Mechanics • Quantum Field Theory • Standard Model of elementary particles and their interactions

First example of embedded symmetry in physical law: • Newton’s law: F = m a • Covariant under rotations F, a changes in the same way under rotation. • Invariant under Galilean transformations F, a do not change.

Mathematics Physics • Calculus • Complex numbers/functions • Differential geometry • Group theory • Hermitian operators, Hilbert space •….

Any global symmetry leads to some conservation law (Noether, 1915). eg., invariance under space translation momentum conservation.


A symmetry of a physical system is a physical or mathematical feature of the system (observed or intrinsic) that is "preserved" under some change. Ex.1: The temperature of a room is invariant under a shift in the measurer's position translational symmetry. Ex.2: Symmetry of mathematical functions: a2c + 3ab + b2c remain unchanged under exchange of a and b.

Symmetry considerations

Electromagnetism Maxwell’s equations: • First attempt to combine electricity and magnetism. • Invariant under Lorentz transformation. • Also invariant under gauge transformation.

• Define scalar (φ) and vector (A) potentials related to electric & magnetic fields : E = −∇φ − ∂A/∂t, and B = ∇ × A • E and B remains unchanged even if we change the potentials as : φ′ = φ − ∂Λ/∂t and A′ = A + ∇Λ, where Λ is a function of (x, t).

Gauge transformation


• Quantum Mechanics is invariant under a change in the phase of the wave function: Ψ’ = e iθ Ψ

• The electromagnetic interaction can naturally be introduced into QM by demanding that the Lagrangian should be invariant under local (space-time dependent) phase transformations: Ψ’ = e iΛ (x,t) Ψ • For historical reasons, this invariance under local phase transformation is called GAUGE symmetry. • However, when the derivative terms in the Lagrangian act on Λ(x,t), the invariance is spoilt due to extra terms. • To cancel these extra terms and restore the invariance, one has to introduce a vector field into the theory. • This vector field transforms under gauge transformations, exactly as the electromagnetic field (as shown in previous slide). Therefore, we identify this vector field with the electromagnetic field which mediates interaction among charged particles.

Gauge symmetries


•The GAUGE principle: The requirement of invariance under gauge symmetry creates the interaction. • Invariance under the symmetry requires the photon to be massless. • This matches well with experimental observation of infinite range of EM interaction.

• Quantum electrodynamics is the most successful theory: predicts correctly the magnetic moment of the electron to 12 significant digits! • This success paves the way to apply similar ideas for weak and strong interactions. • The gauge symmetries involved here are more complicated, but the mediators of interactions could be invoked naturally from the principle of invariance.

• Now carriers of weak interaction are charged (eg. in Beta decay: n p e+ ne) W+, W- should couple to photon Electromagnetic and weak interactions are combined together in a single Electroweak theory Carriers (boson) : photon (γ) , W+, W- and Z 0 . ……… Standard Model encompasses electroweak and strong interactions.

Standard Model of Particle Physics

Nobel prizes in 1979 1984 2004


Spontaneous Symmetry Breaking

In nature we have examples where the symmetry gets broken up spontaneously! • A ferromagnet below Curie temperature has all the spins aligned to the direction of the magnetisation. there is a preferred direction in the system • But above the Curie temperature the spins are randomly oriented all directions are equally preferred.

• Invariance under the symmetry requires all the carrier particles to be massless. • However weak interaction is short-ranged! • Question: How do W and Z particles become massive? SSB

Symmetry disappears at low energy, reappears at high energy. 8/29/2012 14

Higgs discovery and India: K. Mazumdar

1. Francois Englert and Robert Brout at Brussels 2. Peter Higgs in Edinburgh 3. Gerald Guralnik, Carl Hagen and Tom Kibble at London

The mechanism of symmetry breaking in physical systems studied in early 1960s (Nobel prize to Nambu, 2008). During 1964, several groups utilized this idea to explain the phenomenon of mass generation of carrier particles in electroweak theory.

• When the universe was much hotter the particles were massless. • In the process of cooling down some of the symmetries are lost. Electroweak symmetry breaking caused photon to remain massless while W± and Z0 particles became massive. Short range of weak interaction incorporated at low energies.

Origin of mass

Plausible phenomenon:


The price of symmetry breaking : list of the fundamental particles got extended by atleast one new particle of spin 0 The HIGSS BOSON • Simply put, there is an all pervading Higgs field. • All particles necessarily interact with it. •The amount of interaction of a particle in the Higgs field causes its mass. • The Higgs field also interacts with itself as well resulting in its own mass!

The simplest test of this hypothesis is to observe the Higgs boson experimentally. But we did not know its mass, which could be anything between 0 to 1000 GeV! Pre-LHC experiments and other theoretical considerations restrained the range (114 – 750) GeV

LHC is built to find the Higgs boson OR, resolve the issue of mass generation of the carriers of weak interaction.

Predicament!


Why did the Higgs search become so important?

• The Standard Model of particle physics has the ability to predict the results of experiments. • Since all the past experiments match well to the theoretical description of Standard Model, it is certain that the corresponding theoretical description is correct.

• But the issue of electroweak symmetry breaking, or equivalently, the generation of mass is one of the corner stones of the theory. • So success of standard model crucially depended on the confirmation of the “Higgs mechanism” the existence of the Higgs boson. However, the Higgs particle has been elusive to the experiments until now. Onus was on the experiments to really hunt out the Higgs particle.

Notably, the immensely complex LHC project has lived up to the expectations!!!


What happens in LHC experiment

Proton-Proton 1380 bunch/beam Protons/bunch 2. 1011

Beam energy 4 TeV Luminosity 7.5*1033 /cm 2/s Crossing rate 20 MHz Total event rate 5.4*108 Hz Higgs production <1 Hz

Summer, 2012

2 major multipurpose experiments at LHC • A Toroidal LHC Apparatus (ATLAS) • Compact Muon Solenoid (CMS)

• 80 Million electronic channels per experiment, ready for data/25 ns. 20 years to build, 20 years to operate.


Mandate of the experiments :1. Discover Higgs particle or rule out its existence. 2. Elucidate on physics at the new energy range of TeV 3. Search for the candidate of the dark matter in the universe. …….

• Temperature generated at LHC due to proton-proton collision ~1016 0c, compare with sun: 5506 0c, a matchstick: 250 0c

• LHC machine to be maintained at -271 0c vs. Home freezer: -8 0c, Boomerang nebula: -272 0c, Antarctica: -89.2 0c

LHC: The Giant Marvel of Technology

• 100-150 m under the surface and 27 km at 1.9 K (super-fluid Helium) • Vacuum ~ 10-13 Atm. • SuperConducting coils: 12000 tonnes/7600 km


The missing piece we have been after

A slice of CMS detector

• The detector can only “see” γ, e±, µ ±, π±, n, p, K ! • Measure the position and energy-momentum with high resolution.


Cartoon of presently working CMS Detector Hadron Outer calorimeter TIFR, U.Panjab

Silicon preshower of Electromagnetic Cal BARC, U.Delhi

• Designed meticulously for hard collisions • Serving well even for softer ones


• CMS Collaboration: 1740 Ph.D.s + 1535 students (845 for Ph.D.) + 790 engineers from 179 institutes in 41 countries. •Higgs discovery paper has 75 names from India including retired senior physicists.

Only a fraction of 4300 people who made CMS possible.

CMS detector during assembly on surface to be taken down 100 m into the experimental hall.


Today, ~7 Indian groups in CMS, thriving well. • BARC (7 faculty, 2 students) • Delhi U. (6 faculty, 5 students) • IIT, Mumbai (since 2011) (1 faculty) • NISER (under discussion) • Panjab U. (4 faculty, 10 students) • SINP (since 2011) (5 faculty, 9 students) • TIFR (8 faculty, 8 students) • Visva-Bharati U (1 faculty, 2 students) • Logistic support to Sri Lanka • Currently about 35 physicists, 10 engineers + other technical staff, • 40 Ph.D. students (+15 students who have finished Ph.D. already) Significant contribution from India in various fronts, though limited by ‘distance’ and ‘time-zone’ factors.

India-CMS collaboration

Many members in the audience


Salient contributions from India in CMS experiment 1. Detector R&D in 1990s 2. Study of scintillator material for the electromagnetic detector and design of

its granularity 3. Optimization study of tracker detector material/geometry 4. Fabrication of subdetector systems, installation, testing 5. Physics studies for optimization of detector in preparatory stage 6. Software development for detector simulation 7. Studies with test beam, cosmic ray muons 8. Data collection, data quality monitor 9. Understanding of detector performance, possible improvements 10. Calibration of detector 11. Physics analyses, review of collision data leading to publications 12. Several collaboration-wide responsibilities within CMS 13. Representing collaboration in international conferences 14. In CMS grid computing via Tier2 centre 15. Detector upgrade for future operational phases of LHC including R&D

ALL ARE TEAM WORKS 8/29/2012 24


Precursor to discovery

Before collisions at the LHC Study of 1 Billion cosmic ray muons passing through assembled CMS detector test of detector integration, performance of individual subsystems 23 papers in Journal of Instrumentation several works from India including cover of one paper.

During collision phase • Hands on data from the start • Data quality monitor, trigger monitor • Analyses with early data of 2009 • Data collected during 2010 used for physics commissioning, + establishing known results at LHC, + measurement of processes predicted in Standard Model, which are background to discoveries.

Particle Physics of last century rediscovered at early LHC


• Maintain excellent detector performance in spite of harsh situation. • Proper modeling of condition in simulation essential.

Event rate for a given physical process depends on instantaneous luminosity R= σ L Highest value reached till now: L = 7.54 *1033 /cm 2 /s = 7.54 Hz/nb High luminosity many collisions during single bunch crossing

LHC operation

7 TeV

8 TeV 8 TeV 2012

7 TeV 2011

Data used for discovery: 5.1 fb-1 @ 7 TeV 5.3 fb-1 @ 8TeV ~7*1016 p-p collisions


Foundation for Higgs search

Several contributions from India into this plot, including a few theses. 8/29/2012 27


Contributions related to physics and core software

• Each analysis involves , multiple groups to perform different aspects. • Development of analysis strategy, trigger strategy, management of data, handling simulations, determination of efficiency, acceptance, maintaining all information, developing necessary software ,… • No result belongs to a single person/ group/ country

• Key member for detector simulation of overall CMS experiment. • Additional important contribution towards evolution of GEANT package

• Significant involvement in studies oriented more towards subdetector systems e.g., studies of performance of hadron calorimeter, electromagnetic calorimeter,..

More than 160 publications in peer-reviewed journals, based on collision data result of focused and coordinated preparation over long time with great attention to details. Direct significant contribution from India in about 30 published papers.

Towards physics output


Current involvements CMS physics

Key players from India in wide range of topics: • Search for Higgs boson in multiple final states • Electroweak physics • Diboson production • Properties of QCD multi-jets events • Prompt single and double photon production • Soft interactions • Searches for SuperSymmetry • Searches for exotic physics relevant at TeV energy scale resonances, extra-dimensions, substructure of quarks, .. • Model independent search for discovery physics Significant involvement in heavy ion physics as well: • With dimuon final state: Observation of first Z in heavy ion, Quarkonia production and sequential suppression of J/psi, Upsilon. • Inclusive Jets, dijet imbalance, prompt photon, jet shapes, .. Presentation of results in international conferences on behalf of CMS collaboration Significant roles in review of analyses.

Every collision at LHC has interesting physics

Today we celebrate only the discovery of the Higgs boson

Unfortunately, no time to discuss individual topics or highlight Indian contribution towards specific analyses.


Higgs production at LHC

gluon-gluon fusion Vector boson fusion Associated productions with W, Z, top

Theoretical prediction of production rate of Higgs boson as a function of its mass. Strong interaction corrections for the rate Higgs production in gg H process are substantial. First calculated in 2003 by V.Ravindran (HRI, Allahabad), (in the hall) J.Smith and W.L.van Neerven. Nuclear Physics B 665 (2003) 325.


Strategy for experimental Search •Since the Higgs mass is not known, need to consider all the decay modes at different mass values. •Divide the mass region according to the decay mode which is easy to identify and equip the detector accordingly. 1) For Higgs mass below 140 GeV look for H 2γ, H WW(*), H ZZ(*) 2) For mass 140 -180 GeV, H WW, H ZZ(*) 3) Above 180 GeV, H ZZ

High demands on the detectors at lower values of Higgs mass, the natural width is very small, the detector resolution should be excellent.

Branching ratios (%) H WW* : 23 H ZZ* :2.9 H bb : 56 H cc: 2.8 H ττ : 6.2 H µµ: 0.021 H gg : 8.5 H γγ : 0.23 H γ Z : 0.16

For MH= 125 GeV, Γ Η= 4.2 MeV


Higgs decaying to a pair of photons

• Simple and clean signature: final state with 2 energetic photons. • Narrow peak to be identified on top of huge continuously falling background in the invariant mass distribution.

• Crucial for mass resolution: individual energy measurement s and angle between 2 photons.

The calorimeter material chosen to have compact detector with good energy, position, and angular resolutions Excellent mass resolution of about 1%

m2γγ= 2 E1 E2 (1-cosα)

simulation

Work done in India during 1990s : • Radiation hardness test of inorganic crystals, organic scintillators. • Simulation study of crystal granularity in electromagnetic calorimeter.

signal

Background


Reconstructed H 2 photons event in CMS detector


CMS result for 2 photon final state

• Observed significance 4.1 σ • Probability for a background fluctuation to be at least as large as the observed maximum excess at 125 GeV : 20 in a Million.


H ZZ(*) 4leptons • One of the best performing search channels in large range of Higgs mass. easily identifiable final state with energetic electrons, muons little background • Extremely demanding for the experiment requiring highest possible efficiency and lepton identification and isolation. • Mass resolution ~ 1%

Recovery of final state radiation off e, µ

• 2 pairs of oppositely charged leptons of same flavour • From complete information of the final state leptons analyse the angular correlation discriminate against background processes

Lots of work from India in different final states, at the preparatory stages as well as in analyses.


Observed significance 3.2 σ

CMS result from 4lepton final state

Expect: 7.5 signal + 3.8 background events, Observed: 9 events around 125.6 GeV


Higgs search in different final states (total 45)

• Data from 2011 and 2012 • 5 decay modes combined • Excess of events around 125 GeV with significance 5 σ Fitted mass: 125.3 ± 0.7 GeV

Result consistent with poduction of Standard Model Higgs boson

Published in Physics Letters B

High mass Resolution channels


Comparing with Standard Model predictions

Seminar on July 4, 2012 followed by Press release

Link to page and screenshot

http://cms.web.cern.ch/news/observation-new-particle-mass-125-gev

Hindi version of press release put up at CMS public page


Detector hardware from India Outer hadron calorimeter (HO): crucial for containment of energetic hadronic jets improves performance of physics with jets and missing energy crucial for discovery Preparation Simulation and test beam studies Fabrication at TIFR and Panjab University. • 432 plastic scintillator trays ~ 2.5 m* 40 cm • 72 honeycomb housing

• Quality control at every stage tools developed test of light transmission across spliced fibres study of signals due cosmic ray muons, radioactive sources • Accessories for 2154 photo-detector readouts

• Control boards for next version of photo-sensors (Silicon Photo Multiplier) being fabricated and tested.

CMS achievement award to HO installation team 8/29/2012 39


From Tile to Tray

Tower structure for calorimeter

Tray packing

Construction of HO

WLS fibres spliced to clear optical fibres. Optical fibres grouped together as pigtail, connected to photosensors few meters away

Tray: 4-6 units + Wavelength shifting fibres

8/29/2012 40

Higgs discovery and India: K..Mazumdar

Silicon Preshower

Participation from BARC+ Delhi University • Fabrication at industry at Bangalore with close supervision of physicists, engineers. • Characterization studies. • India supplied 1500 silicon strip detectors out of total 4200 covering an area of about 17 m2 • Detector: 32 strips with a pitch of 1.8mm and are of 63 mm x 63 mm • First ever construction of large area silicon detectors in the country. •High quality of detectors comparable to international suppliers.

Position sensitive silicon preshower in endcap enhances performance of electromagnetic calorimetry in CMS.

Crucial for Higgs 2 photon decay, to differentiate from background processes mimicking same final state.


32-strip silicon detector developed by BARC

Front end electronics developed by CERN

Assembly of detectors: Micromodules & ladders (15 man-months from India)

Ladder with 7 modules

Silicon strip detectors

Prototype & production design

Assembled ladders in endcap psoition


Resistive Plate Chambers

Restoration of the full TDR, RE4 (±)

Present experiment runs with 3 endcaps

• Currently CMS detector has limited coverage for muon trigger. • To be enhanced with additonal layer of RPC in endcap region. for |η| =(1.2 -1.6) • Improvement in physics with muons.

Total 200 chambers : CERN, Belgium, India 50 chambers to be made in India (BARC, Chandigarh) + cooling accessories for 200 chambers

Common technical specification and protocols for production and QC discussed and agreed among the three sites with detailed Database for production and tests maintained and available to all.


Cu Faraday with Mylar : 25 sets

Cu Read Out Strips : 50 sets

Screen Covers : 25 sets

Platform for mylar cutting

Production of Chambers and cooling accsessories

Some features for cooling accessories • Semi-hard DHP copper for the plates, & pipes (70 to 95 HV10) • Cutting, bending and testing of Cu-tubes • Cu pipes soldered to Cu plates @ 200oC (with cooling) • Leak test with Argon at 20 bar Plexiglass spacers for guiding co-axial

cables


• Upgrades are required to improve the physics performance with future operation of LHC (higher energy, higher luminosity). • Current detector design based on technologies available 20-15 years back.

• India is participating in several of the R&D activities for the upgrade: A) Photo-sensor replacement in hadron calorimeter: Phase 1: Silicon photomultiplier tube for HO Control boards bein fabricated and tested in India. Phase 2: a) CMOS based development of SiPM: R&D being pursued well. b) R&D for front and backend electronics for improvement in readout of hadron calorimeter including improved trigger capabilities. B) Instrumentation of forward region for muon measurement R&Ds with micro-gap chambers C) Silicon based tracking detectors which are radiation hard

Upgrade of CMS detector


Conclusion

• The discovery of a resonance is just the beginning of an exciting and important era in our understanding for the deepest secrets of nature. • Miles to go before we sleep : need to learn the property of this resonance in detail. Presumably it is THE HIGGS BOSON. • LHC machine is performing fantastically Stay tuned for the updates! • Proton-on-proton collisions at energy 8 TeV will conclude by end of this year. • In next 2 years’ time LHC will be ready to deliver collisions at almost double the energy. • There may be other significant results/discoveries in near future.


We are extremely fortunate to be part of the saga of the unbelievable pursuit for the unimaginable.

Thanks

• To all the funding agencies for financial supports. • To our respective home institutes for support and encouragement.


Backup


Current involvements in Physics Physics Analyses in p-p collision: • Search for the Higgs boson (Delhi, Panjab, SINP, TIFR, Visva-Bharati) • Electroweak physics (Panjab, TIFR): Drell-Yan process, W-charge asymmetry • Diboson production ( Delhi, Panjab , TIFR): Wγ, WW, ZZ processes • Vector Boson + jet production (Panjab, TIFR) • Study of properties of QCD (TIFR, Panjab, Visva Bharati) event shape, inclusive cross-section multi-jets events • Prompt photon studies (Delhi) • Soft interactions (Panjab, TIFR): underlying events, multi-parton interactions • SUSY searches : SUSY particles, MSSM Higgs (TIFR) • Exotica searches (several) resonances in di-tau, photon final states (Panjab, SINP, TIFR) extra-dimensions in diphoton channels (SINP) • Model independent analysis for discovery (Delhi) Analyses with Heavy-Ion data: • Study of suppression in the production of J/psi, upsilon, Z resonances (BARC) • jet shapes (BARC) 8/29/2012 49 Higgs discovery and India: K. Mazumdar

• Hardware (R&D, fabrication, quality control) monitor, maintenance, calibration . (BARC, Delhi, Panjab, TIFR, +recently SINP). • Physics before collisions at LHC: preparatory studies with simulation, contributions in LHCC and other milestone documents, trigger and analyses strategy (TIFR). • Software: detector simulation, GEANT specific developments (TIFR, now SINP). • Test Beam activities for HCAL (TIFR, Panjab, + recently SINP). • LHC Tier2 Grid computing centre for CMS (TIFR). • Analysis of real data contribution in publications --- Cosmic muons recorded in CMS (Panjab, TIFR) --- Collision data (both p-p and Pb-Pb) for physics, analyses reviews (everybody) • Detector monitor, strategy for improvement in performance of subdetectors, calibration (HCAL: Panjab, SINP, TIFR ECAL: Delhi, SINP, Tracker: SINP). • Serving in CMS-wide committees (Delhi, SINP, TIFR). • Representing CMS collaboration in international fora (everybody).

Participation of India in CMS experiment till now

8/29/2012 50

1998 Construction of surface buildings for CMS begins.

2000 LEP shut down, construction of cavern begins.

2004 Cavern completed.

10 September 2008 First beam in CMS.

23 November 2009 First collisions in CMS.

30 March 2010 First 7 TeV collisions in CMS.

4 July 2012 Announcement: evidence for a particle at about 125 GeV.

Timeline for CMS experiment

Roman coins excavated from site

http://cms.web.cern.ch/news/observation-new-particle-mass-125-gev

https://cms-docdb.cern.ch/cgi-bin/PublicDocDB/RetrieveFile?docid=6116&filename=CMShiggs2012_Hindi.pdf 8/29/2012 51 Higgs discovery and India: K. Mazumdar

Pecuiliarities about experiments

• Huge mammoth size detectors 40m X 50 m X 50 m, weighing 12.5 kTon • The magnetic field in CMS experiment 4 Tesla ~ 105 times earth’s field • Silicon-based detector at the heart with total area 250 sq. m • 80 thousand scintillator crystals (96% metal by mass), supported by 0.4 mm thick glass/carbon fibre structure. •Brass used as absorbing material came from dismantled artillery shells of Russian warships. •1 sec. running of the experiment produces data volume ~ 10K encyclopedia Britannica. •Data production to reach ~ Tbyte/day when LHC runs in full force. • Good fraction of data analysis from remote centres. 8/29/2012 52 Higgs discovery and India: K. Mazumdar

Our service/tasks in CMS • Requirement: every signing author: 3 months of service • New members: 6 months of service during first year. • Partial exemption for contribution towards CMS computing efforts via CMS T2 at TIFR. • Numerous types of service works envisaged in CMS, some examples: 1. Remote Computing shifts: monitoring worldwide the computing efforts of CMS at BARC, Chandigarh, TIFR 2. Remote Tracker offline monitor from SINP 3. RPC detector studies at CERN Central Facility (RPC-CAF) 4. Detector Physics related: prompt feedback (PFG), data quality monitor (DQM) 5. Study, Monitoring, maintenance of trigger criteria (Offline) 6. Support, maintenance/creation of documentation for softwares, workbook. 7. Membership of some of the committees 8. Central shifts at experimental site: trigger, data acquisition, control, monitor, ..

Almost everybody is doing his/her bit, sometimes extra, compensating for others 8/29/2012 53 Higgs discovery and India: K. Mazumdar

quest for the higgs boson - tifrmazumdar/talks/dst_cms.pdf · 2012-08-31 · the higgs boson...

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