ATLAS first run scenarios for B physics Paula Eerola, Lund University On behalf of the ATLAS collaboration Beauty 2006, Oxford, September 2006

Paula Eerola, Lund University Beauty 2006, Oxford, September This talk includes: Introduction Introduction A summary of the LHC start-up scenario A summary of the LHC start-up scenario B-production in the LHC commissioning run (450 GeV GeV) until the end of B-production in the LHC commissioning run (450 GeV GeV) until the end of The first physics run at 14 TeV The first physics run at 14 TeV a) Role of B-physics and Heavy Quarkonia events in understanding the detector, trigger and online/offline software with 100 pb -1. b) Strategies for B-physics with 100 pb fb -1

Paula Eerola, Lund University Beauty 2006, Oxford, September Introduction ATLAS is a general-purpose experiment, with an emphasis on high-p T physics beyond the Standard Model. ATLAS is a general-purpose experiment, with an emphasis on high-p T physics beyond the Standard Model. ATLAS has also capabilities for a rich B-physics programme, thanks to precise vertexing and tracking, high-resolution calorimetry, good muon identification, and a dedicated and flexible B-physics trigger scheme. ATLAS has also capabilities for a rich B-physics programme, thanks to precise vertexing and tracking, high-resolution calorimetry, good muon identification, and a dedicated and flexible B-physics trigger scheme. ATLAS has a well-defined B- physics programme for all stages of the LHC operation, from the commissioning run all the way up to the highest luminosity running. ATLAS has a well-defined B- physics programme for all stages of the LHC operation, from the commissioning run all the way up to the highest luminosity running.

Paula Eerola, Lund University Beauty 2006, Oxford, September ATLAS B-physics goals: precision measurements and new physics  m s,  s,  s, the weak phase  s Measurement of B s properties Precise measurements of the branching ratios and asymmetries Rare decays Asymmetry parameter  b, P b, life- time measurements  b polarization measurements B c mass, , QCD/EW interplay B c mesons sin(2  ) +  NP CP violation CP-violation parameters CP-violation parameters B-hadron parameters: masses, lifetimes, widths, oscillation parameters, couplings, b-production, etc. B-hadron parameters: masses, lifetimes, widths, oscillation parameters, couplings, b-production, etc. Search for New Physics effects: very rare decay modes, forbidden decays/couplings, etc. Search for New Physics effects: very rare decay modes, forbidden decays/couplings, etc.

Paula Eerola, Lund University Beauty 2006, Oxford, September News from the LHC machine

Paula Eerola, Lund University Beauty 2006, Oxford, September P. Jenni ATLAS Overview Week July 2006 A new LHC schedule and turn-on strategy was presented to the CERN SPC and Council June The main features of the new schedule are:  The beam pipe closure date will be end of August  LHC commissioning run with collisions at the injection energy (√s =900 GeV), scheduled November Luminosity typically L = cm -2 s -1.  During the commissioning run at 900 GeV the LHC will be a static machine, no ramp, no squeeze, to debug the machine and the detectors.  Then there will be a shut-down (typically 3 months) during which the remaining machine sectors will be commissioned without beam to full energy (√s = 14 TeV).  After that the LHC will be brought into operation for the first physics run at 14 TeV, with the aim to integrate substantial luminosity by the end of 2008: goal several fb -1 by the end of New LHC machine schedule

Paula Eerola, Lund University Beauty 2006, Oxford, September The commissioning run b cross section dominates at both √s = 900 GeV and 14 TeV. At √s = 900 GeV the b fraction of total inelastic events is ~10 x smaller than at 14 TeV. The run in 2007 will primarily be a detector and computing commissioning run, much more than a physics run. The run in 2007 will primarily be a detector and computing commissioning run, much more than a physics run. A few weeks of stable running conditions at the injection energy. A few weeks of stable running conditions at the injection energy. b b

Paula Eerola, Lund University Beauty 2006, Oxford, September Triggers for the commissioning running √s = 0.9 TeV, L = cm -2 s -1,  inel =40 mb 4 kHz interaction rate √s = 0.9 TeV, L = cm -2 s -1,  inel =40 mb 4 kHz interaction rate Commissioning the detector, the trigger, the offline reconstruction and analysis chains Commissioning the detector, the trigger, the offline reconstruction and analysis chains Data taking with loose level-1 (LVL1) single muon triggers (p T >5 GeV) or minimum bias triggers Data taking with loose level-1 (LVL1) single muon triggers (p T >5 GeV) or minimum bias triggers The High Level Trigger (HLT) in pass-through mode for testing The High Level Trigger (HLT) in pass-through mode for testing See J. Kirk’s talk on ATLAS triggers See J. Kirk’s talk on ATLAS triggers

Paula Eerola, Lund University Beauty 2006, Oxford, September DecayRate N(ev) for 1 d* N(ev) for 30 d* Min bias hadron   5  X |   |< * Hz b   5  X 60 * Hz b   5  3  X 2 * Hz 2 * Hz b  J/  5  3  X 0.1 * Hz pp  J/  5  3  X 1 * Hz pp   5  3  1.7 * Hz *) 1 full day is 8.64 * 10 4 s, 30% machine and data taking efficiency assumed √s √s =900 GeV, L=10 29 cm -2 s -1 Rates and statistics b b b

Paula Eerola, Lund University Beauty 2006, Oxford, September Event statistics with B and Quarkonium muonic decays bb   5 X bb   5  3 X pp  J/  (  5  3) X pp   (  5  3) X √s √s =900 GeV, L=10 29 cm -2 s -1 h   5 X bb  J/  (  5  3)X Number of days of data taking Number of events in ATLAS after all cuts 30% machine and data taking efficiency assumed. Reconstruction and trigger efficiencies included.

Paula Eerola, Lund University Beauty 2006, Oxford, September % data taking efficiency included. Efficiency of trigger and analysis cuts included. Event statistics for the commissioning run W  e Z  ee bb   5  3 X pp + bb  J/  (  5  3)X √s √s =900 GeV, L=10 29 cm -2 s -1

Paula Eerola, Lund University Beauty 2006, Oxford, September Conclusions for the commissioning run  Heavy flavours b and c will be a source of ~4.7k single muons and ~370 di-muons given 30 days of beam (30% machine and data taking efficiency).  Soft LVL1 single-muon trigger can be used to select those events.  High-level trigger in pass-through mode.  The dimuon sample includes about 90 J/  and 130  – can serve for first tests of mass reconstruction.  Any heavy flavour physics? Low statistics will not allow separating direct and indirect J/  sources. S/B a factor of 10 worse than at the nominal LHC c.m. energy. Muons from hadron decays dominate the trigger rate due to worse S/B and softer spectrum. The ratio of J/  and  events may be the best bet.

Paula Eerola, Lund University Beauty 2006, Oxford, September The first physics run: B-physics strategies - Serve as a tool for understanding the trigger and the detector: calibration, alignment, material, magnetic field, event reconstruction. - Physics: cross-section measurements at new energy - QCD tests and optimization of B-trigger strategies. - Control B-channels will be used to verify if we measure correctly well known B-physics quantities (with increasing integrated luminosity  real measurements). - Control B-channels will also be used to prepare for high- precision B-measurements and searches for rare decays: tagging calibration, production asymmetries, background channels specific for rare decays.

Paula Eerola, Lund University Beauty 2006, Oxford, September Trigger priorities for the first physics running √s = 14 TeV, L = cm -2 s -1 √s = 14 TeV, L = cm -2 s -1 Many customers for the data Many customers for the data –Data for commissioning the detector, the trigger, the offline reconstruction and analysis chains –Data samples high-p T physics studies –Data samples for B-physics studies Scope depends on luminosity and available HLT resources Scope depends on luminosity and available HLT resources –Data samples for “minimum-bias” physics studies Needed also for tuning Monte Carlo generators used in other physics studies Needed also for tuning Monte Carlo generators used in other physics studies

Paula Eerola, Lund University Beauty 2006, Oxford, September Trigger menus for B-physics The ATLAS B-physics programme is based on LVL1 muon triggers The ATLAS B-physics programme is based on LVL1 muon triggers –Inclusive low-p T single-muon triggers at low luminosity –Low-p T dimuon triggers at higher luminosities Search for specific final states (exclusive or semi- exclusive) in HLT Search for specific final states (exclusive or semi- exclusive) in HLT –Refine muon selection, then reconstruct tracks from B decays in the inner detector (ID) Tracks in ID: track search in the full ID or in regions given by LVL1 Regions of Interests (RoIs), depending on the HLT processor capacity and luminosity Tracks in ID: track search in the full ID or in regions given by LVL1 Regions of Interests (RoIs), depending on the HLT processor capacity and luminosity See J. Kirk See J. Kirk EM RoI e+e+ e-e-

Paula Eerola, Lund University Beauty 2006, Oxford, September B cross-section at LHC All LHC experiments plan to measure B-cross section in proton- proton collisions.All LHC experiments plan to measure B-cross section in proton- proton collisions. Measurements will cover different phase space – will be complementary.Measurements will cover different phase space – will be complementary. Partial phase-space overlaps: LHCb, ATLAS, CMS, ALICE - opportunity for cross-checks.Partial phase-space overlaps: LHCb, ATLAS, CMS, ALICE - opportunity for cross-checks. Methods of measurement for low- and medium-p T events in ATLASMethods of measurement for low- and medium-p T events in ATLAS b   6 X ; b →  6  3 X; Exclusive channels B + → J/  K +, B 0 → J/  K 0* b- correlations: B → J/  X + b    =  J/  -   b b b

Paula Eerola, Lund University Beauty 2006, Oxford, September Statistics for cross-section and correlation measurements DecayStatistics with 10 pb -1 Statistics with 100 pb -1 b   6  X 40 M 40 M 400 M 400 M c   6  X 20 M 20 M 200 M 200 M b   X 2 M 2 M 20 M 20 M B  J/  X and b   X B + → J/  K B 0 → J/  K 0* b b c

Paula Eerola, Lund University Beauty 2006, Oxford, September Decay Statistics with 100 pb -1 Measurement pp → J/  6  3  1000 k R(b → J/  )/R(  pp → J/  R(pp →  /R(  pp → J/  b  J/  6  3  X 400 k 400 k  6  3  100 k 100 k B-physics with 100 pb -1 : J/  and  b b

Paula Eerola, Lund University Beauty 2006, Oxford, September B physics with 100 pb -1 : exclusive B decays Decay Statistics with 100 pb -1 Measurement B + → J/  K Important reference and control channel: new channels (B →  ) relative to this. B 0 → J/  K 0* Control channels: masses, lifetimes etc. Sensitive checks for understanding the Inner Detector. B 0 → J/  K s B s → J/   b → J/  Bs → Ds Bs → Ds Bs → Ds Bs → Ds  Hadronic channels – only prepare methods for later measurements.

Paula Eerola, Lund University Beauty 2006, Oxford, September The reconstructed masses and lifetimes of the well- known control channels are sensitive tests of those detector features which have a strong impact on B- physics measurements. DecayStatistics 100 pb -1 Statistical error on lifetime World av today (stat + syst) B+B+B+B+ B + → J/  K % 0.4 % B0B0B0B0 B 0 → J/  K 0* % 0.5 % BsBsBsBs B s → J/  % 2 % bbbb  b → J/  % 5 % Lifetime “reconstruction” with control channels

Paula Eerola, Lund University Beauty 2006, Oxford, September B physics with 100 pb -1 : sensitivity to rare exclusive B decays Decay Statistics or limit with 100 pb -1 Measurement today B + →  K + 23 Belle today 80? Belle today 80? B 0 →  K 0* 12 B s →  9  b →  3 B s →  6.4×10 -8 at 90% C.L. CDF currently 8.0x10 -8 at 90% C.L.

Paula Eerola, Lund University Beauty 2006, Oxford, September B 0 s → µ + µ - with 100 pb -1, 10 fb -1 and 30 fb -1 Integrated LHC luminosity N(signal) after all cuts N(backgr.) after all cuts ATLAS upper limit for Br(B 0 s → µ + µ - ) at 90% C.L. CDF upper limit for Br(B 0 s → µ + µ - ) at 90% C.L. 100 pb -1 ~ 0 ~ × × fb fb -1 ~ 7 ~ × fb fb -1 ~ 21 ~ 60 7 ×10 -9 Discovery channel B 0 s → µ + µ -

Paula Eerola, Lund University Beauty 2006, Oxford, September Conclusions Commissioning run at 900 GeV, very low luminosity Commissioning of the detector, the trigger, the offline reconstruction and the analysis chains. Commissioning of the detector, the trigger, the offline reconstruction and the analysis chains. In 30 days ~4.7k single muons and ~370 di-muons from b and c: first tests of trigger and offline muon reconstruction. In 30 days ~4.7k single muons and ~370 di-muons from b and c: first tests of trigger and offline muon reconstruction. 90 J/  and 130  : first tests of mass reconstruction. 90 J/  and 130  : first tests of mass reconstruction. First physics run at 14 TeV, 100 pb -1 – 1 fb -1 Measurements of B masses and lifetimes: a sensitive test of understanding the detector – alignment, material, magnetic field, event reconstruction etc. Measurements of B masses and lifetimes: a sensitive test of understanding the detector – alignment, material, magnetic field, event reconstruction etc. Cross-section measurements at new energy: QCD tests and also optimization of B-trigger strategies. Cross-section measurements at new energy: QCD tests and also optimization of B-trigger strategies. J/  and  measurements. J/  and  measurements. Control B-channel measurements to prepare for further B physics – precision measurements and new physics measurements. Control B-channel measurements to prepare for further B physics – precision measurements and new physics measurements. With 100 pb -1 ATLAS can achieve a sensitivity of 6.4×10 -8 in the discovery channel Br(B 0 s → µ + µ - ), which is at the level of current Tevatron results. With 100 pb -1 ATLAS can achieve a sensitivity of 6.4×10 -8 in the discovery channel Br(B 0 s → µ + µ - ), which is at the level of current Tevatron results.

Paula Eerola, Lund University Beauty 2006, Oxford, September Thank you!

Paula Eerola, Lund University Beauty 2006, Oxford, September BACKUP SLIDES

Paula Eerola, Lund University Beauty 2006, Oxford, September Process Cross-section at √s = 14 TeV Cross-section at √s = 900 GeV Total LHC bb cross section 500 bbbb25 bbbb Total LHC inelastic  70mb40mb Min bias hadron   6(5)  X |   |< nb nb b   6(5)  X nb60nb b   6(5)  3  X* 200nb2nb b  J/  6(5)  3)  X* 7nb nb pp  J/  6(5)  3  X* 28nb1nb pp   6(5)  3  9nb1.7nb *) Dimuon p T cuts for muon reconstruction and identification are: (6, 3) GeV at 14 TeV and (5, 3) GeV for 900 GeV. For both muons |  |<2.5. Cross sections in ATLAS for muonic channels b b b

Paula Eerola, Lund University Beauty 2006, Oxford, September  The figure shows sources of low-p T muons at 14 TeV.  Muons from hadron decays in flight (“h” in the figure) have a softer spectrum than muons from b.  At 900 GeV their relative contribution is larger – b fraction of total inelastic cross section ~ 10 smaller than at 14 TeV. single-muon di-muon all h h b b c c J/  Sources of low-p T single and double muons LVL1 muon trigger 14 TeV and cm -2 s -1 b

Paula Eerola, Lund University Beauty 2006, Oxford, September Cross sections for several dominant channels: in LHC (yellow) and in ATLAS volume (rest).14TeV900GeV Total LHC inelastic (NSD)  70mb40mb Total LHC bb cross section 500 bbbb25 bbbb jet p T >15GeV |  15GeV |  <2.524 bbbb Min bias   X |   |< nb1400nb b-jet p T >15GeV |  15GeV |  <2.5370nb jet p T >50 GeV |  50 GeV |  <2.545nb bb   X |   |< nb60nb bb   X |   |< nb2nb pp   |   |<2.5 9nb1.7nb pp  J/  X |   |<2.5 28nb1nb b-jet p T >50 GeV |  50 GeV |  < nb bb  J/  X |   |<2.5 7nb0.1nb *)  muon pT cuts for 14TeV (900 GeV)

Paula Eerola, Lund University Beauty 2006, Oxford, September rates 30d = 10 6 s jet p T >15GeV |  15GeV |  < Hz Min bias   X |   |< Hz b-jet p T >15GeV |  15GeV |  < Hz jet p T >50 GeV |  50 GeV |  < Hz bb   X |   |< Hz bb   X |   |< Hz 200 pp   |   |< Hz 170 pp  J/  X |   |< Hz 100 b-jet p T >50 GeV |  50 GeV |  < Hz 63 bb  J/  X |   |< Hz GeV cm -2 s -1 rates, statistics

Paula Eerola, Lund University Beauty 2006, Oxford, September bb   5 X bb   5  3 X pp+bb  J/  (  5  3) X pp   (  5  3) X Event statistics with B and Quarkonium muonic decays √s √s =900 GeV, L=10 29 cm -2 s -1 40% machine and data taking efficiency assumed. No reconstruction efficiencies included.

Paula Eerola, Lund University Beauty 2006, Oxford, September % data taking efficiency included. Efficiency of all analysis cuts included. W  e Z  ee √s √s =900 GeV, L=10 29 cm -2 s -1

Paula Eerola, Lund University Beauty 2006, Oxford, September Detector configuration during the first physics run B-layer OK. B-layer OK. ID complete, only TRT C-wheels staged ID complete, only TRT C-wheels staged HLT configuration: full 45kHz LVL1 capacity. HLT configuration: full 45kHz LVL1 capacity.