Andrea Ventura University of Salento & INFN Lecce on behalf of the ATLAS Collaboration New Trends in High-Energy Physics Alushta, Crimea, Ukraine, September

Andrea VenturaAndrea VenturaUniversity of Salento & INFN LecceUniversity of Salento & INFN Lecce

on behalf of the on behalf of the ATLAS CollaborationATLAS Collaboration

New Trends in High-Energy PhysicsNew Trends in High-Energy Physics

Alushta, Crimea, Ukraine, September 5, 2011Alushta, Crimea, Ukraine, September 5, 2011

Lecce

05/09/2011 A. Ventura - ATLAS overview

The The LHCLHC is a proton-proton collider running since is a proton-proton collider running since March 2010 at March 2010 at 7 TeV 7 TeV center-of-mass energycenter-of-mass energy

ATLASA Toroidal LHC ApparatuS

LHCLHC presently presently (Summer 2011)(Summer 2011):: Peak luminosity Peak luminosity

2.4·102.4·103333cmcm-2-2ss-1-1

>1000 bunches >1000 bunches colliding in colliding in ATLASATLAS

50 ns bunch 50 ns bunch spacingspacing

5.7 collisions per 5.7 collisions per bunch crossingbunch crossing

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30003000 scientists and scientists and 10001000 students from students from 174174 institutions in institutions in 3838 countries: countries: Albany, Alberta, NIKHEF Amsterdam, Ankara, LAPP Annecy, Argonne NL, Arizona, UT Arlington, Athens, NTU 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 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 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, 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, 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, TU Dresden, JINR Dubna, Duke, Edinburgh, Frascati, Freiburg, Geneva, Genoa, Giessen, Glasgow, Göttingen, LPSC Grenoble, Technion Haifa, Hampton, Harvard, Heidelberg, Hiroshima IT, Indiana, Innsbruck, 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, 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, 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, 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, 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, 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 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 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 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 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, 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, Tokyo ICEPP, Tokyo MU, Tokyo Tech, Toronto, TRIUMF, Tsukuba, Tufts, Udine/ICTP, Uppsala, UI Urbana, Valencia, UBC Vancouver, Victoria, Waseda, Washington, Weizmann Rehovot, FH Wiener Neustadt, Valencia, UBC Vancouver, Victoria, Waseda, Washington, Weizmann Rehovot, FH Wiener Neustadt, Wisconsin, Wuppertal, Würzburg, Yale, YerevanWisconsin, Wuppertal, Würzburg, Yale, Yerevan

05/09/2011 A. Ventura - ATLAS overview 3

ATLAS is a multi-purpose collider detector designed for high precision measurements and for searches beyond the Standard Model.

Physics domain of interest includes: Measurements from QCD processes, B-

physics, W/Z, top, tau, massive di-bosons Higgs searches within and beyond SM New W’/Z’ bosons, SuperSymmetry,

ExtraDimensions and various Exotic Physics scenarios


Examples of searches for new Examples of searches for new resonances resonances shown here (many more results given by F. Derue F. Derue for SM and N. Ruckstuhl for BSM) 4


2T solenoid, toroid system (∫Bdl=1-7.5 Tm)2T solenoid, toroid system (∫Bdl=1-7.5 Tm) Tracking in Tracking in |η||η|2.52.5calorimetry in calorimetry in |η||η|4.94.9

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Design requirements High granularity 4 coverage in solid angle Fast response and readout Radiation hardness

Performance specifications Large acceptance Very good particle ID Precise vertex reconstruction Excellent Jet & Etmiss resolution


• • Inner trackerInner trackerσ/pσ/pTT 0.038%p0.038%pTT 1.5%⨁1.5%⨁

• • EM calorimeter EM calorimeter σ/E σ/E 10%/√E 0.7%⨁ 10%/√E 0.7%⨁

• • Hadronic calorimeterHadronic calorimeter σ/σ/EE 50%/√E 3%⨁50%/√E 3%⨁

• Muon spectrometerMuon spectrometerΔpΔpTT/p/pTT<10% up to 1 TeV<10% up to 1 TeV

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2010

2011

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In 2010: Proton proton collisions ATLAS recorded 45 pb-1 of pp

collisions at 7 TeV In 2011:

Running since March @ 7 TeV Peak luminosity 2.4·1033cm-2s-1

Up to 200pb-1 collected per week >2.5 fb-1data recorded so far Plan is to possibly reach 4-5 fb-1

before the end of the year Beyond:

LHC will run in 2012 Then, long shutdown and run at

higher energy.


High data-taking efficiency achieved (>95%)

Operational fractions of single detectors very high (>97%)

Data collected in each analysis depend on the specific detector requirements defined

Inner Trackers Calorimeters Muon detectors Magnets

Pixel SCT TRTLArEM

LAr Had

LAr Fwd

Tile MDT RPC CSC TGC Solenoid Toroid

99.9 99.8 100 89.0 92.4 94.2 99.7 99.8 99.7 99.8 99.7 99.3 99.0

SubdetectorNumber of channels

Approximate operational

fractionPixels 80 M 96.9 %SCT Silicon Strips 6.3 M 99.1 %TRT Transition Radiation Tracker 350 k 97.5%LAr EM Calorimeter 170 k 99.8 %Tile Calorimeter 9800 97.5 %Hadronic Endcap LAr calorimeter 5600 99.6 %Forward LAr Calorimeter 3500 99.8 %LVL1 Calorimeter trigger 7160 99.9 %LVL1 Muon RPC trigger 370 k 99.5 %LVL1 Muon TGC trigger 320 k 100 %MDT Muon Drift Tubes 350 k 99.7 %CSC Cathode Strip Chambers 31 k 97.7 %RPC Barrel Muon Chambers 370 k 97.0 %TGC Endcap Muon Chambers 320 k 98.1 %

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Flexible trigger menu definition continuosly updated with luminosity

Primary (unprescaled) triggers in 2011 3·1033 cm-2s-1 menu include: Electrons: pT>22 GeV Muons: pT > 20 GeV Jets: pT > 240 GeV EtMiss > 60 GeV (Di)photons : pT > 80 (20) GeV …

Tighter triggers planned for 5·1033 menu


electronselectrons

muonsmuonsjetsjets

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Raw data are reconstructed at Tier-0 within 2 days Calibration and Data Quality performed for physics analysis Data are ready for analysis on the Grid within 1 week


Full number of ATLAS jobs per dayFull number of ATLAS jobs per day

SimulationSimulation

AnalysisAnalysis

March 2011 July 2011

Up to 800k jobs per day are processed on Tier-1 & Tier-2’s Analysis Simulation Reprocessing Various

productions Present results

concern data taken until end-July

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Good resolution and linearity down to very low pT for electrons


Excellent di-muon mass resolution (about 2% at the Z peak)

Good resolution on EETTmissmiss

tested on a wide range of ΣET (comparison pp and PbPb)ATLAS-CONF-2010-

057

Systematic error on Jet Energy Scale known to < 3% on a wide jet pT range


ATLAS-CONF-2011-032

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Good data/MC agreement in di-photon invariant mass spectrum even at very low energy (at 0 mass < 20 MeV)


SV0 b-tagging algorithm tuned for 40-60% efficiency against 0.2-1% mistag rate for 20 < pT

jet < 150 GeVATLAS-CONF-2010-099

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For most of 2011 data, 50 ns bunch trains running at LHC

Relevant in-time and out-of-time pileup, with average of <<μμ>=5.7 >=5.7 superimposed events

Distributions of μ for MC in all analyses shown have been reweighted to reproduce data


Z→μμ event with 11 primary verticesZ→μμ event with 11 primary vertices

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Cross sections of several SM processes

Theoretical uncertainties calculated at NLO or higher

Significant improvements in precision from 2010 to 2011 data

After many years, deep knowledge of detector performance


Stat. errorStat+syst.+lumi. error

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More details on SM results in F. Derue’s talkMore details on SM results in F. Derue’s talk

Many interesting Higgs decay channels under investigation Possible hints are at 120-140 GeV (see N. Rucksthul’s talk)


ATLAS-CONF-2011-112

H

ATLAS-CONF-2011-111

H WW(*)ll

At the moment, combining all channels and using up to 2.3 fb -1, ATLAS excludes mH in [146,232] [256,282] [296,466] GeV

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In MSUGRA limits on gluino/squark masses have been significantly increased from 2010 to 2011


0 leptons channel 1 lepton channel

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Di-jet resonancesDi-jet resonances Dilepton resonancesDilepton resonances

e-e- resonances resonances

Some examples of searches for peaks in invariant mass Some examples of searches for peaks in invariant mass distributions are shown in the following slidesdistributions are shown in the following slides

More details on More details on BSM searches in BSM searches in

N. Ruckstuhl’s talkN. Ruckstuhl’s talk18

At least two jets with pT>30GeV, ||<2.8

Searches for peaks in the mjj spectrum

Most relevant excess in [1.16,1.35] TeV (not significant)


ATLAS-CONF-2011-095

QCD parametrization

BUMPHUNTER tomography

95% CL limit on new physics cross section for simple-gaussian resonance in the region [0.9,4.0] TeV for 4 values of width/mean of mjj

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Three physics models analyzed No evidence of new physics

found with respect to the expected SM QCD background


2010 analyses: New J Phys 13 (2011) 053044

ATLAS-CONF-2011-095

Model95% CL Limits (TeV)

Expected Observed

Excited quarks q* 2.77 2.91Axigluons 3.02 3.21Color Octet Scalar 1.71 1.91

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ATLAS-CONF-2011-083*

Examined scenarios: Z’ (SSM, E6) Randall-Sundrum graviton Contact interactions

Events with two same-flavor leptons Searches for peaks in the mmllll spectrumspectrum

Main SM background is Z/*ll Excellent agreement Data-MC

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No evidence found for new physics signal for various BSM models On 2010 also limits determined for

contact interaction dimuon >5.1 TeV Phys Lett B700 (2011) 163-180


ATLAS-CONF-2011-083*

Model95% CL Limits (TeV)Expected Observed

Z’ (E6) 1.50-1.64 1.50-1.64

Z’ (SSM) 1.83 1.83R-S G, k/M=0.1 1.61 1.63R-S G, k/M=0.01 0.7 0.7

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Events with exactly 1e + 1μ , isolated and with pT >25 GeV

New improved 95% CL limits on BR for ν̃_ mass in SUSY RPV models and also for heavy neutral gauge boson Z’ with LFV couplings.


ATLAS-CONF-2011-109

ν̃ ν̃ ττ → → eeμμ

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95% CL Lower Limits95% CL Lower Limits

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ATLAS experiment at LHC has collected so far >2.5 fb-1 and is working very well.

As of now, no definitive evidence of Higgs production, excluded (@ 95% CL) within SM over the region [146,232] [256,282] [296,466] GeV.

More and more stringent mass limits obtained on SUSY and new BSM phenomena.

Now investigating unexplored regions to possibly discover new physics new physics with increased integrated luminosity (possibly 4-5 fb-1 until end of 2011).



Graviton excitations expected in the di-photon spectrum in R-S warped ED models

Backgrounds: SM , jet and multijets


ATLAS-CONF-2011-044

Number of Extra Dimensions

95% CL Limits (GeV)

Expected Observed

G, k/M=0.02 503 545G, k/M=0.1 975 920

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Events with only one high-pT jet large Et

miss and no leptons Three sets of thresholds used:

lowPt, highPt, veryHighPt EW background: Z/W +jets


ATLAS-CONF-2011-096

MC normalized to data in an orthogonal lowPt subsample

Good agreement between data and SM expected bckg. within stat.+syst. errors

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No evidence found for LED ADD model physics scenarios

Model independent 95% CL limits on A: low/high/veryHighPt : 1.7/0.11/0.035 pb

Limits improved by factors larger than 2 compared to CDFCDF and LEPLEP combined


ATLAS-CONF-2011-096

Number of Extra Dimensions

95% CL Limits (TeV)

Expected Observed

n=2 2.98 3.16 n=3 2.44 2.56 n=4 2.18 2.27 n=5 2.03 2.10 n=6 1.92 1.99

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Documents

Andrea Ventura University of Salento & INFN Lecce on behalf of the ATLAS Collaboration New Trends in High-Energy Physics Alushta, Crimea, Ukraine, September