Highlights and Searches in ATLAS Dave Charlton University of Birmingham on behalf of the ATLAS Collaboration 1 EPS-HEP Grenoble, 25 July 2011
Highlights and Searches in ATLAS ATLAS status and data Performance Dave Charlton Beyond Standard Model searches University of Birmingham A few words on the Higgs on behalf of the ATLAS Collaboration Other plenary talks: EW, top, b, QCD, H 2 EPS-HEP Grenoble, 25 July 2011
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38 Countries 174 Institutions 3000 Scientists 1000 Students 4
38 Countries 174 Institutions 3000 Scientists 1000 Students Albany, Alberta, NIKHEF Amsterdam, Ankara, LAPP Annecy, Argonne NL, Arizona, UT Arlington, Athens, NTU Athens, Baku, IFAE Barcelona, Belgrade, Bergen, Berkeley LBL and UC, HU Berlin, Bern, Birmingham, UAN Bogota, Bologna, Bonn, Boston, Brandeis, Brasil Cluster, Bratislava/SAS Kosice, Brookhaven NL, Buenos Aires, Bucharest, Cambridge, Carleton, CERN, Chinese Cluster, Chicago, Chile, Clermont-Ferrand, Columbia, NBI Copenhagen, Cosenza, AGH UST Cracow, IFJ PAN Cracow, SMU Dallas, UT Dallas, DESY, Dortmund, TU Dresden, JINR Dubna, Duke, Edinburgh, Frascati, Freiburg, Geneva, Genoa, Giessen, Glasgow, Göttingen, LPSC Grenoble, Technion Haifa, Hampton, Harvard, Heidelberg, Hiroshima IT, Indiana, Innsbruck, Iowa SU, Iowa, UC Irvine, Istanbul Bogazici, KEK, Kobe, Kyoto, Kyoto UE, Lancaster, UN La Plata, Lecce, Lisbon LIP, Liverpool, Ljubljana, QMW London, RHBNC London, UC London, Lund, UA Madrid, Mainz, Manchester, CPPM Marseille, Massachusetts, MIT, Melbourne, Michigan, Michigan SU, Milano, Minsk NAS, Minsk NCPHEP, Montreal, McGill Montreal, RUPHE Morocco, FIAN Moscow, ITEP Moscow, MEPhI Moscow, MSU Moscow, LMU Munich, MPI Munich, Nagasaki IAS, Nagoya, Naples, New Mexico, New York, Nijmegen, Northern Illinois, BINP Novosibirsk, Ohio SU, Okayama, Oklahoma, Oklahoma SU, Olomouc, Oregon, LAL Orsay, Osaka, Oslo, Oxford, Paris VI and VII, Pavia, Pennsylvania, NPI Petersburg, Pisa, Pittsburgh, CAS Prague, CU Prague, TU Prague, IHEP Protvino, Regina, Rome I, Rome II, Rome III, Rutherford Appleton Laboratory, DAPNIA Saclay, Santa Cruz UC, Sheffield, Shinshu, Siegen, Simon Fraser Burnaby, SLAC, South Africa, Stockholm, KTH Stockholm, Stony Brook, Sydney, Sussex, AS Taipei, Tbilisi, Tel Aviv, Thessaloniki, Tokyo ICEPP, Tokyo MU, Tokyo Tech, Toronto, TRIUMF, Tsukuba, Tufts, Udine/ICTP, Uppsala, UI Urbana, Valencia, UBC Vancouver, Victoria, Waseda, Washington, Weizmann Rehovot, 5 FH Wiener Neustadt, Wisconsin, Wuppertal, Würzburg, Yale, Yerevan
2T solenoid, toroid system (∫Bdl=1-7.5 Tm) ATLAS Detector ATLAS Detector Tracking to |η|=2.5, calorimetry to |η|=4.9 6
Data Collection Data Collection 2010 operation: gradual (~exponential) ramp-up of instantaneous luminosity 2010: 45 pb -1 2011 – sustained delivery of integrated luminosity efficiency ε≈ 94% 1 fb -1 of 2011 data recorded by 17 June 1.75 Peak luminosity 1.28 x 10 33 cm -2 s -1 2011 to-date: ε≈95% Best in a day: 63 pb -1 Results with up to 1.2 fb -1 7
Pile-up Challenge Pile-up Challenge 50 ns bunch trains for ~all 2011 data Substantial in- and out-of-time pileup ● Much progress understanding impact on performance, with data & simulation ● Continuing detailed performance studies Characterise by μ – mean number of interactions per bunch-crossing <μ>=5.7 Z → μμ event with 11 primary vertices 8
Luminosity Measurement Luminosity Measurement Absolute luminosity calibration ● beam-beam (van der Meer) scans One scan in Oct 2010 ● both with special and physics beams Quality of VdM scans was excellent Several relative measures of instantaneous luminosity in physics ● Powerful cross-checks Pileup dependence of different luminosity estimators → small additional uncertainty in 2011 relative to 2010 ∆L/L = ±3.4% (2010, prel) ∆L/L = ±3.7% (2011, prel) see also V Hedberg parallel talk,C Gabaldon poster
trigger L1 item L1 Rate EF Rate Trigger Trigger (Hz) (Hz) e20_medium EM14 8500 50 2e12_medium 2EM7 5700 1 Primary triggers are kept stable, e.g. ● Inclusive e p T >20 GeV g80_loose EM30 700 3 2g20_loose 2EM14 750 2 ● Inclusive μ p T >18 GeV mu18 MU10 5300 40 ● Inclusive jet p T >180 GeV 2mu10 2MU10 100 1 ● E T miss > 60 GeV xe60 XE40 300 4 ● Diphoton p T > 20 GeV j180 J75 200 6 ● ... tau29medium_xe35 TAU11_XE20 3800 6 Such triggers are not prescaled tau16_e15 TAU6_EM10 7500 6 Supplemented by supporting & monitoring triggers Sophisticated and flexible menus j75_xe45 J50_XE20 500 10 Rates at 10 33 cm -2 s -1 Reliable extrapolation to higher luminosity/pileup 20 GeV e trigger at L1, L2 & EF
Detector Performance and Data Quality Detector Performance and Data Quality Data-taking efficiency >95% Operational fractions of detector also >~97% Data for analyses depends on specific detector requirements Of 1.24 fb -1 collected by end June, between 1.04 and 1.21 fb -1 for most results presented “All good” fraction will increase by ~7% in reprocessing campaign starting now (fine- grained flagging of calo noise bursts) 11
Computing Grid Delivers Physics Computing Grid Delivers Physics Production jobs running at CERN Tier-0 vs time Data preparation: ● First-pass reco. at Tier-0 within ~2 days ● Calibration/DQ good for physics analysis ● Data analysable on Grid within ~1 week July March Tier-1 and Tier-2's process ~ ⅔ M jobs per day ● simulation ATLAS jobs per day across all Tier-1 & Tier-2s ● re-reconstruction (campaigns) 800k ● group production (ntuples...) ● physics analysis analysis The high quality computing system allows us to show results on data taken until the end of June simulation Payback for the years of investment and hard work March July
Performance for Physics Performance for Physics e 2010 jets ATLAS-CONF-2011-032 3 % Measure ε to ±1% at high p T from data, also down to 4 GeV, using J/ψ, W, Z E scale to 0.3-1.6% over |η|<2.47 to 1 TeV see also T Theveneaux-Pelzer poster 2011 pileup → higher prel. JES error for E T <100 GeV jets ( ±2-5% for |η|<2.1 ) Perfect MC align t μ |η|<2.5 miss E T Comparing pp and PbPb Measure ε to ±<1% at high p T from data Δp T /p T =13% at 1 TeV (barrel)
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see also A Gibson parallel talk,T Dietzsch poster Dijet Resonance Search Dijet Resonance Search Search for peaks in the m jj spectrum Examples: q*, axigluon, colour-octet scalar models – also generic limits q* ATLAS-CONF-2011-095 Model Expected limit Observed limit Obs. 2010 q* 2.77 2.91 2.15 Generic limits on axigluon 3.02 3.21 2.10 dijet resonances of c.o.s (s8) 1.71 1.91 - specific widths 95% CL limits in TeV 2010 analyses studying also angular distributions: New J Phys 13 (2011) 053044
Dilepton Resonances Dilepton Resonances e + e − and μ + μ − invariant mass distributions Look for Z' and RS graviton (G*) production Z → ee ee Z' 264k selected Z → ee Model Observed 95% CL limit 2010 Z' SSM 1.83 TeV 1.048 TeV G* (k/m PL =0.1) 1.63 TeV - μμ 16 see also T Hryn'ova parallel talk, S Heim, S Viel posters
eμ μ Resonance Search Resonance Search e Search in s-channel for eμ resonances e - d ν τ λ 312 λ′ 311 d μ + Example straw-man models: ● ν τ in RPV SUSY, with only λ' 311 , λ 312 ≠ 0 ● SM-like Z' with non-diagonal couplings σ(Z') < 11 fb at 95% CL for m Z' >700 GeV ATLAS-CONF-2011-109 17 see also T Hryn'ova parallel talk
miss Lepton + E T miss Lepton + E T Search in transverse mass spectra for e/μ + E T miss W → μ ν Constrains a sequential SM-like W' ~4.3 M selected W → μν ℓ W' ν Channel Expected limit Observed limit Obs. 2010 e ν 2.17 2.08 1.37 μ ν 2.08 1.98 1.29 both 2.23 2.15 1.49 18 95% CL limits in TeV see also T Hryn'ova parallel talk
see also S Lai parallel talk, F Seifert poster Physics with Taus Physics with Taus Z ττ → cross- Preliminary Preliminary section μh μh measurement eh eμ 2010 2010 μμ Constraints on A/H/h → ττ production in SUSY models eμ4 ν , eτ had 3 ν , μτ had 3 ν 2010 2010 channels 19
miss Monojet: Jet + E T miss Monojet: Jet + E T High-p T jet opposite ~no activity ● Standard Model: Z → νν ● Large-extra dimensions with unobserved graviton 4+n dimensions, 4+n-dimensional Planck scale M D 3.16 TeV 2.27 1.99 TeV TeV Lower limits on m D If we only consider ŝ < m D ², m D > 1.68 TeV for n=6 20 see also A Gibson parallel talk, V Rossetti poster
jet = 602 GeV p T miss = 523 GeV E T A high-p T monojet event – SM interpretation Z → νν + jet 21
Massive Di-Bosons Massive Di-Bosons Low cross-sections: observation is a step towards searching with these final states σ tot (WZ)=21.1± 3.1 ±1.2±0.9 pb σ tot (ZZ)=8.4± 2.7 ± 0.4 ±0.3 pb 2.3 2.8 0.7 SM NLO: 17 pb SM NLO: 6.5 pb ATLAS-CONF-2011-099 ZZ WZ M T (W → ℓν) in events with a Z → ℓℓ candidate ATLAS-CONF-2011-107 WW, WZ and ZZ diboson signals established in double leptonic decay channels 22 WW: ATLAS-CONF-2011-110 see also A Oh parallel talk
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