RECENT RESULTS FROM THE TEVATRON AND LHC Suyong Choi Korea University
Contents The experiments Physics Results Heavy flavor Higgs Searches SUSY Searches Exotica Summary and Outlook 2
The Tevatron (1983 – 2011) D-ZeroExperimentD-ZeroExperiment CDFExperimentCDFExperiment 3
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5 >90% data taking efficiency Recorded up to 130 pb -1 per day >90% data taking efficiency Recorded up to 130 pb -1 per day
Measurement of Electroweak Cross Sections 6
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Using full data of 9.7 fb-1 Neural network technique 8
2011 data of 1 fb -1 Boosted decision tree technique 9
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11 Γ = ± (stat.)± (syst.) ΔΓ = ± 0.018(stat.) ± 0.006(syst.) s = ± 0.083(stat.) ± 0.027(syst.)
TOP PHYSICS 12
Top Pair Production Tevatron pb 7 TeV LHC pb 13
Single Top Production Tevatron – 3.6 pb 7 TeV LHC – 86 pb 14
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Physics with Top 16
Tevatron Top Quark Mass Combination GeV uncertainty!
Top Quark Mass at LHC muon+jets channel with 2 b-jet tagged jets 2391 events selected, 92% purity Simultaneous determination of m t,reco and JES. Likelihood fit to extract m t Systematics dominated 18 CMS-PAS-TOP
Determination of Top Quark Width 19
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2 sigma deviation Consistent asymmetry for different charged lepton samples 22
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Asymmetry seen already in lepton rapidity 25
D-Zero 2 sigma deviation No statistically significant enhancement seen dividing into subsamples 26
Charge asymmetry at LHC 27
Top Quark Spin Correlation Top quark decays before hadronization Spin information reflected in direction of decay products On average, no preferred spin polarization But, event-by-event, there is correlation in polarization Lepton is the most sensitive probe of top quark spin polarization ATLAS spin correlation analysis 28
ATLAS Observation D-Zero Evidence for Spin correlation 29
HIGGS SEARCHES 30
CMS Higgs Search Channels Some updated and new channels w.r.t. last year 31
Events separated into 5 classes according to MVA output Photon quality Background modeling: polynomial fit, sideband method 32 CMS-PAS-HIG
Consistency P-value - Probability for background to produce fluctuation as large as observed GeV 1.6 global significance
34 Data excludes Higgs 95% CL – – – – – 147.0
35
CMS Combined Higgs Exclusion Limits Observed 95 CL: – 600 GeV 36 CMS-PAS-HIG
ATLAS Combined Higgs Exclusion 37 Excluded regions: 110 – – – 539
SUSY Higgs Searches 38 One of many categories
SUSY SEARCHES 39
SUSY Searches at CMS Full 2011 data explored Many final states and techniques Single lepton + jets +MET Opposite sign dilepton Same sign dilepton Etc. Interpretation in simplified model spectra Described in J. Alwall, et. Al., PRD ,
Simplified Model Topologies Direct decays Assume sufficient mass splitting between particles 41
Simplified Model Topologies 1 or 2 Cascade decays Mass of intermediate particle 42
Simplified Model Topologies Chargino neutralino 43
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Mass ranges probed 45
EXOTICA 46
47 CMS-EXO
Search for Dilepton Resonances Probe masses of up to 2 TeV Z’ SSM > 2.32 TeV KK graviton (k/M Pl =0.1) > TeV 48 CMS-EXO
Search for Extra Dimensions in Diphoton Channel 49 Phys. Rev. Lett. 108, (2012)
Search for Dijet Resonances 50 CMS-EXO
Search 4 th generation t’ quark 51 CMS-EXO
Summary and Outlook 2011 was a great year for CMS Successful operation, calibration, comprehensive studies High-statistics top quark samples Allowed mass range for SM Higgs narrowed significantly Probed TeV mass ranges 8 TeV center-of-mass energy with more luminosity in 2012 More precision measurements Kinematic reach in searches extended Definite answer regarding Higgs searches 52
53 >90% data taking efficiency Recorded up to 230 pb -1 per day >90% data taking efficiency Recorded up to 230 pb -1 per day Results from 2012 data will be shown in Summer Conferences
BACKUP 54
D-Zero 55
D-Zero Detector Silicon microstrip track er Central fiber tracker 2 T solenoid field Liquid Argon Calo. Good resolution, e/h 3 layer muon system Toroidal magnetic field Top event candidate 56
CMS 검출기 57
Rediscovery of known particles 58 Courtesy of Jim Pivarski Well-understood detector, trigger and software performances
CLs Confidence level for signal hypothesis 59
p-value 60