Status Report from the CMS Experiment

Status Report of The CMS ExperimentChristos LeonidopoulosCERN-PHon behalf of the CMS Collaboration102nd LHCC Meeting, CERN7 July 2010

1The Collaboration2AACHEN-1, AACHEN-3A, AACHEN-3B, ADANA-CUKUROVA, ANKARA-METU, ANTWERPEN, ATHENS, ATOMKI, AUCKLAND, BARI, BEIJING-IHEP, BOGAZICI, BOLOGNA, BOSTON-UNIV, BRISTOL, BROWN-UNIV, BRUNEL, BRUSSEL-VUB, BRUXELLES-ULB, BUDAPEST, CALTECH, CANTERBURY, CARNEGIE-MELLON, CATANIA, CCCS-UWE, CERN, CHANDIGARH, CHEJU, ILLINOIS-CHICAGO, CHONNAM, CHUNGBUK, CHUNGLI-NCU, COLORADO, CORNELL, DEBRECEN-IEP, DELHI-UNIV, DEMOKRITOS, DESY, DONGSHIN, DUBLIN-UCD, DUBNA, EINDHOVEN, FAIRFIELD, FERMILAB, FIRENZE, FLORIDA-FIU, FLORIDA-STATE, FLORIDA-TECH, FLORIDA-UNIV, FRASCATI, GENOVA, GHENT, HAMBURG-UNIV, HEFEI-USTC, HELSINKI-HIP, HELSINKI-UNIV, HEPHY, IOANNINA, IOWA, IPM, ISLAMABAD-NCP, JOHNS-HOPKINS, KANGWON, KANSAS-STATE, KANSAS-UNIV, KARLSRUHE-IEKP, KHARKOV-ISC, KHARKOV-KIPT, KHARKOV-KSU, KONKUK-UNIV, KOREA-UNIV, KYUNGPOOK, LAPP, LAPPEENRANTA-LUT, LIP, LIVERMORE, LONDON-IC, LOUVAIN, LYON, MADRID-CIEMAT, MADRID-UNIV, MARYLAND, MEXICO-IBEROAM, MEXICO-IPN, MEXICO-PUEBLA, MEXICO-UASLP, MILANO-BICOCCA, MINNESOTA, MINSK-INP, MINSK-NCPHEP, MINSK-RIAPP, MINSK-UNIV, MISSISSIPPI, MIT, MONS, MOSCOW-INR, MOSCOW-ITEP, MOSCOW-LEBEDEV, MOSCOW-MSU, MOSCOW-RDIPE, MUMBAI-BARC, MYASISHCHEV, NAPOLI, NEBRASKA, NICOSIA-UNIV, NORTHEASTERN, NORTHWESTERN, NOTRE DAME, NUST, OHIO-STATE, OVIEDO, PADOVA, PAVIA, PEKING-UNIV, PERUGIA, PISA, POLYTECHNIQUE, PRINCETON, PROTVINO, PSI, PUERTO RICO, PURDUE, PURDUE-CALUMET, RAL, RICE, RIE, RIO-CBPF, RIO-UERJ, ROCHESTER, ROCKEFELLER, ROMA-1, RUTGERS, SACLAY, SANTANDER, SAO PAULO, SEONAM, SEOUL-EDU, SEOUL-SNU, SHANGHAI-IC, SKK-UNIV, SOFIA-CLMI, SOFIA-INRNE, SOFIA-UNIV, SPLIT-FESB, SPLIT-UNIV, ST-PETERSBURG, STRASBOURG, SUNY-BUFFALO, TAIPEI-NTU, TALLINN, TASHKENT, TBILISI-IHEPI, TBILISI-IPAS, TENNESSEE, TEXAS-TAMU, TEXAS-TECH, TIFR-EHEP, TIFR-HECR, TORINO, TRIESTE, UCDAVIS, UCLA, UC RIVERSIDE, UC SANTA BARBARA, UC SAN DIEGO, UNIANDES, VANDERBILT, VILNIUS-ACADEMY, VILNIUS-UNIV, VINCA, VIRGINIA-TECH, VIRGINIA-UNIV, WARSAW-IEP, WARSAW-INS, WARSAW-ISE, WAYNE, WISCONSIN, WONKWANG, YEREVAN, ZAGREB-RUDJER, ZURICH-ETH, ZURICH-UNIV

182 Institutions 3000 scientists and engineers 2000 Authors2Reminder: we went from this

3.8T Superconducting SolenoidAll Silicon Tracker (Pixels and Microstrips)Lead tungstate E/M Calorimeter (ECAL)Redundant Muon System(RPCs, Drift Tubes, Cathode Strip Chambers)Hermetic (|| 1 GeVMC based correction applied according to cluster and energy0.43 nb-1 1.46M 0 0.43 nb-1 25.5k 25.5K PT() > 0.5 GeV, PT(pair) > 2.5 GeVCalorimetry: 0 and Statistics refer to < 0.5 nb-1 Very useful tool to intercalibrate the crystals Good agreement in width and Signal/Background ratio Masses agree with expectations to within 1%29DATADATAMCMC29Calorimetry: Missing ETCalorimetric MET (GeV)30

Jets reconstructed with the anti-kT R=0.5 algorithm Dijet selection : Jet P > 25 GeV, > 2.1, || < 3 Loose ID cuts on number of components and neutral/charged energy fraction30

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/Onia

Calorimetric di-jet events32Dijet mass(j1, j2)

# of Calo TowersFraction of EM energy in Calo-Jets

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/OniaTracking distributionsMuon distributions35

Global Muons: matched tracks from Muon system and Tracker Global Muons and pT distributions dominated by light hadron decay muons (red) good agreement with MC prediction, including heavy flavor decays (blue) punch-through (black) fakes (green)

Global Muons

pT spectrum distribution

distributionTracking distributions36 distribution distributionTracker Material Budget37

distribution distributionTracker Material Budget38

pixel cluster charge

Tomography

39

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/Onia

3D impact parameter value and significance all tracks with pT> 1GeV belonging to jets with pT > 40 GeV and || < 1.5 - PFlow Jets anti-kT R=0.5)

Excellent alignment and general tracking performance

b-tagging 3D IP significance414142

Two b-jets candidateb-tagging example4242

CMS experiment at LHC, CERNRun 136100 / Event 2568584382010-25-5 03:43:48 CEDTB- J/yK- candidate

CMS experiment at LHC, CERNRun 136100 / Event 2568584382010-25-5 03:43:48 CEDTB- J/yK- candidate

All other tracks: pT > 1.0 GeV/c

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/OniaParticle Flow Particle Flow: Full Event reconstruction Topological matching between charged particle momenta measured with tracker with clusters in calorimeter Corrects for energy loss along trajectories Better precision, full event info

High-level object: requires holistic detector view Excellent tracker High E/M calorimeter granularity (0.017 0.017) Strong magnetic field to separate tracks

CMS very well suited for P-Flow reconstruction4646Particle Flow MET47

Particle Flow MET48

Laser forgotten onNeed cleaning strategies developed based on timing constraintsParticle Flow MET49

Comparison between calorimetric and Particle-Flow MET(Minimum bias events)

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/Onia51J/ +Ongoing studies: Momentum scale corrections by studying mass as a function of , pT (material budget) Efficiency studies with tag-n-probe Flight distance with determination of prompt and bJ/ + terms

Signal events: 4150 222Sigma: 43.1 1.9 (stat.) MeVM0 : 3.094 0.001 (stat.) GeVS/B= 5.22/dof = 1.056 nb-1 5152J/ + : The Best OfSelection of central (barrel), high-quality dimuons: Resolution: 43.1 MeV 21.0 MeV56 nb-1

5253J/ + plus friends

60 nb-1 5354J/ + plus friendsNot enough statistics to disentangle all resonances (yet)

60 nb-1 54

Event selection: Muon id cuts Isolation, pT and MET cuts Monte Carlo: Event count normalized to integrated luminosityW candidateW observation

55# of candidate (MT > 50 GeV) = 137# of expected signal (MT > 50 GeV) = 128 # of expected background (MT > 50 GeV) = 737 nb-1 55 Event selection: Muon id cuts Loose isolation, pT cuts Monte Carlo: Event count normalized to integrated luminosityZ + observation

Z candidate

56#of candidate = 25#of expected signal = 24.7 #of expected background = 0.08 60 nb-1 56

Detector & Physics PerformanceCalorimetryJets

Tracking b-tagging

Muon EWK/Onia Particle Flow Electron EWK/Onia58J/ e+e Higher background, tighter selection compared to muon channel Challenging analysis, Particle-Flow selection crucial Very promising preliminary results, signal clearly established

Signal events: 132 14Sigma: 98 12 (stat.) MeVM0 : 3.070 0.013 (stat.) GeV37 nb-1 58Two event selections: Basic electron ID, no MET cuts More advanced electron ID, cuts on ET, MET, ETW e observation 59

173 candidates with MT > 50 GeVMC: Sig=163, Bkg=5196 candidates with MT > 50 GeVMC: Sig =176, Bkg =1151 nb-1 59 Event selection: Two electrons with ET > 20 GeV Monte Carlo: Event count normalized to integrated luminosityZ e+e observation Zee candidate60

52 nb-1

#of candidate = 18#of expected signal = 19 #of expected background = 0.8 60Summary7 TeV collisions: a very exciting run!The CMS detector is working according to design First performance results are very encouraging Its behavior can be reproduced in Monte Carlo simulation Our level of understanding for this early commissioning phase is very advanced

The rediscovery of the SM has begun We are setting the grounds for challenging it as early as the end of 2010

6262EpilogueThe technology of the LHC accelerator and experiments is unprecedented

Massive amount of work and preparation invested in building and commissioning hardware & softwareBut: we do not forget that the real challenges are still ahead (for all of us)

We should consider this truly exciting period as the beginning of a marathon6363The Beginning of The Journey

Credit for Da Vinci drawings: Sergio Cittolin Credit for material used in this talk: LHC, CMS64Backup65

The CMS DetectorMUON BARRELCALORIMETERS PixelsSilicon Microstrips210 m2 of silicon sensors9.6M (Strip) & 66M (Pixel) channels

ECAL76k scintillating PbWO4 crystals Cathode Strip Chambers (CSC)Resistive Plate Chambers (RPC)Drift Tube Chambers (DT)Resistive Plate Chambers (RPC)Superconducting Coil, 4 TeslaSteel YOKETRACKERMUONENDCAPSHCALPlastic scintillator/brasssandwich

6666Muon pT resolution with cosmics

1B events of (mostly muon) cosmic events collected make muons the best understood reconstructed object in CMS

Compare muon pT in upper, lower detector halves to evaluate resolution6712% resolutionat 1 TeV

0 , distributions

Relative calibrationprecision ~ 2%target ~0.5% at 10pb-10s and ECAL calibration0 and symmetry ECAL Barrel ECAL Barrel68HLT: CPU performance & pile-up69First look at impact of pileup on CPU-performance

1 coll/bunch2 coll/bunchHave deployed multiple-vertex trigger to facilitate pile-up studies with real data6970J/ + Run range: 132440-139370 Common selection: No scraping Tracker Muons of opposite charge Pixel layers >= 2 Tracker hits >= 12 Tracker chi2 < 3 Mu pT > 2.5 Mu segments >=2 Matched L1DoubleMuOpen vertex Prob > 0.05 70Run 136100, Event 256858438 Measured Parameters:

3-trk vertex that is displaced from the PV by 2mm (18s).

Our background is dominated by real J/yDimuon mass in data (points) compared to MC (hist)