LHCb Status and Prospects Doris Eckstein (CERN) on behalf of the LHCb Collaboration 3rd International Conference on Flavor Physics Chungli, Taiwan, 3-8 October 2005 Introduction Status and Performance of Detector Physics Prospects - Examples

Introduction LHCb experiment to study CP violation in B-hadron decays LHC: pp-collisions @ 14TeV full spectrum of B-hadrons produced B-cross-section large ~500mb Interactions/crossing Pile-up at high luminosity: choose 2x1032 cm-2 s-1 most events have single interactions 1012 b-hadrons per nominal year of data taking (2 fb-1) LHCb: forward spectrometer 15-250mrad acceptance 2 January 2019 Doris Eckstein, ICFP2005

Introduction cont’d LHCb: study CP violation look for New Physics rare B decays Need: efficient trigger on leptons and hadrons efficient particle ID for flavour tagging and background rejection good proper time resolution for time dependent measurements of Bs decays good B mass reconstruction for background rejection 2 January 2019 Doris Eckstein, ICFP2005

Introduction - LHCb detector Kinematics Magnet + Trackers Calorimeters Particle ID RICH1 and RICH2 Calorimeters Muon system Vertex Reconstruction VELO Tracking system VELO Trigger Tracker Inner/Outer Tracker p 250 mrad 10 mrad 2 January 2019 Doris Eckstein, ICFP2005

Detector Status - VELO Downstream Interaction region 42mm 8mm ~1m Silicon microstrip sensors 42 modules around interaction region R-F geometry Strip pitch varies from 40mm to 100mm Sensors close to beam (8 mm) Beetle FE chip VELO hybrid Module production starting 2 January 2019 Doris Eckstein, ICFP2005

Detector Status - VELO Ensure high resolution  short extrapolation distance  small multiple scattering  Sensors are at 8 mm from beam  Sensors in secondary vacuum Roman Pots Mechanics to allow for retraction Vacuum Vessel and stand manufactured. Mechanics to move VELO ready. 2 January 2019 Doris Eckstein, ICFP2005

Detector Performance - Vertexing dIP = 14mm+35mm/pT Impact parameter resolution proper time t=lm/p Proper time resolution is dominated by B vertex resolution Bs→Dsp Impact parameter resolution crucial for proper time resolution ~40 fs for most channels 2 January 2019 Doris Eckstein, ICFP2005

Detector Status - Magnet ∫Bdl = 4 Tm Warm dipole magnet (Al), Fe yoke = 1600 t Regularly reverse field to control systematics Installed in 2004 Field mapping ongoing 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – Tracker Outer Tracker Inner Tracker for Region of high occupancy cm T1, T2, T3 made of Outer Tracker and Inner Tracker Trigger Tracker Measurement in fringe field of magnet Covers full detector acceptance Provide pt for Trigger (together with VELO) 2*2 layers Silicon microstrip sensors 500mm thickness ~200mm readout pitch Production started 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – Tracker Tracking behind the Magnet – IT and OT Inner Tracker: only 2% of area, but 20% of tracks  Silicon microstrip sensors 11 cm strips, ~200mm pitch Outer Tracker: 3 stations each made up of 4 double-layers of Kapton/Al straw tubes glued together to form modules two-sensor ladders: 410 mm thickness Single sensors: 320 mm thickness Modules in production Module production close to completion 2 January 2019 Doris Eckstein, ICFP2005

blue = reconstructed tracks red = detected hits blue = reconstructed tracks VELO TT T1 T2 T3 Detector Performance – Tracking tracks passing through full spectrometer: e ~ 95%, a few percent of ghost tracks Momentum resolution Dp/p ~ 0.4% Mass resolution BsDsp+ Typical sm~15 MeV 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – RICHes For hadron ID Efficient p/K separation up to 100 GeV Aerogel C4F10 gas CF4 gas RICH2: High momentum tracks CF4: 16 - ~100 GeV RICH1: Low momentum tracks Aerogel: 2 - ~10 GeV C4F10: 10 - ~60 GeV 5cm Aerogel n=1.030 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – RICHes Novel photon detectors: Hybrid Photon Detectors  Si pixel detectors encapsulated in photo-tube ~ 500 tubes, each with ~1000 pixels Production underway HPD tubes RICH2 ready for transportation HPDs in production RICH1 in production Outside RICH2 Spherical mirrors aligned to 50mrad 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – Calorimeters Scintillating Pad Detector/PreShower 2.5 X0 Pb between 2 Scintillator planes size corresponds to size of ECAL pads in production Hadronic Calorimeter (HCAL) Fe/Scintillator tile calorimeter, 5.6 lI Granularity varies transversally 13x13 and 26x26cm SPD/PS HCAL HCAL ECAL installed, commissioning starts 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – Calorimeters Electromagnetic Calorimeter (ECAL) Pb-Scintillator Shashlik, 25 X0 granularity varies transversally from 1 to 3 Rm sE/E = 10% /E  1% resolution from testbeam installed Comissioning started 2 January 2019 Doris Eckstein, ICFP2005

Detector Status – Muon System MWPC’s Triple-GEM in inner part of M1 (highest rate region) Projective pad geometry (used in Trigger) Muon-Identification Efficiency ~95% for <1% pion misidentification MWPC’s in production GEM production will start soon calorimeters 2 January 2019 Doris Eckstein, ICFP2005

Detector Performance – Particle ID K/p separation by RICH Pion id efficiency ~97% Pion misid ~3% Kaon id efficiency ~88% Kaon misid ~12% Signal Background Large rings: aerogel Small rings: C4F10 Lepton ID by Calorimeters and Muon System: <e(mm)> = 94% <e ( m)> = 1% <e(ee )> = 81% <e( e)> = 1% 2 January 2019 Doris Eckstein, ICFP2005

Trigger 40 MHz 1 MHz Recent change: L0 High pt hadron, lepton, g Flag multiple interactions, busy events Hardware (custom boards), latency 4ms Calo, Muon, Pileup, SPD L1 Combined high pt, high IP Software (PC farm), partial event information,decision in 1ms VELO, TT HLT Software (PC farm), complete event, 10ms Full information from detector On tape 40 MHz 1 MHz 40 kHz 2 kHz L0, L1 L0×L1 Recent change: Full detector information read out at 1 MHz Zero suppressed Combined software trigger 2 January 2019 Doris Eckstein, ICFP2005

Physics Prospects – Baseline Measurements Bs mixing (new physics effects in box diagrams) Dms from Bs→Dsp fs and DGs from Bs→J/yf CKM angles from different processes to over-constrain unitary triangle sin(2b) from Bd → J/yKs Important check/comparison with B-factories g from various channels different sensitivity to new physics g from Bs → DsK time dependent asymmetries g from B → pp, Bs → KK time dependent asymmetries g from B → D0K*0 decay rates a from Bd → rp rare B decays (b → s processes, NP now yet well constrained) Bs → mm down to SM BR Bd → K*mm : measure forward-backward asymmetry 2 January 2019 Doris Eckstein, ICFP2005

Physics Prospects – Dms Decay time resolution Bs  Ds-p+ Proper time resolution ~ 40 fs S/B~3 80k events/year Dms=25ps-1 1 year of LHCb data Statistical uncertainty on amplitude of Bs oscillation as function of Dms 5σ measurement in 1 year of running for Δms up to 68 ps-1 (far beyond Standard Model expectation Δms < 26 ps-1) oscillations clearly observed with 1 year of data taking! Once oscillations are established, determine Δms with σ(Δms) ~ 0.01ps-1 stat. 2 January 2019 Doris Eckstein, ICFP2005

Physics Prospects – g from Bs→DsK u b c Bs Ds- K+ Interference of tree diagrams yields phase of g+fs fit four time dependant decay rates: Bs → Ds-/+ K+/- fs measured through Bs→J/yf Free of new physics contributions in penguin diagrams Measured g not affected by new physics in Bs mixing Discrepancy with indirect g from CKM fit will signify new physics in mixing Sensitivity after 1 year: Dms 20ps-1 25ps-1 30ps-1 s(g) 14.2 16.2 18.3 2 January 2019 Doris Eckstein, ICFP2005

Physics Prospects – g from B→hh Bd ->pp 25k events/year Bs -> KK 37k events/year Bd/s /K /K Bd/s time dependent asymmetries for Bd→pp and Bs→KK ACP(t) = Adir cos(Dm t) + Amix sin(Dm t) Parameters: Mixing phases fd or fs  through Bd→J/yKs and Bs→J/yf Penguin/Tree=deiq U-spin symmetry: dpp=dKK, qpp=qKK 4 observables, 3 unknowns: solve for g Dms=20ps-1, DGs/Gs=0.1, g=65o, q=160o, d=0.3, Fs=-0.04 One year: s(g) ~ 5+ uncertainty from U-spin symmetry breaking Sensitive to new physics in penguin 2 January 2019 Doris Eckstein, ICFP2005

Summary The detector is designed for precise vertexing and tracking and excellent particle identification. LHCb has a high performance trigger dedicated to B physics. LHCb will extend the B physics results from B-factories and Tevatron due to the high statistics expected and the full spectrum of B-hadrons available. LHCb spectrometer construction is progressing well. Overall commissioning will start end of 2006. We are looking forward to first data in 2007! 2 January 2019 Doris Eckstein, ICFP2005