The LHCb Experiment II Detector XXXIV SLAC Summer Institute, 17-28 July, 2006 Tatsuya NAKADA CERN and Ecole Polytechnique Fédérale de Lausanne (EPFL)
1) Introduction Physics requirements for the detector - large acceptance for the both b and b final states - trigger sensitive on hadronic, semileptonic and leptonic final states - efficient, flexible and robust trigger - lepton and hadron particle identification e/μ/ / /K/p - good propertime resolution - good mass resolution T. Nakada SLAC Summer Institute, July 2006 2
pt of B-hadron 10 2 ATLAS/CMS 100 μb LHCb LHCb Spectrometer 10 230 μb 1-2 0 2 4 6 eta of B-hadron Shifted IP point Good mass and eigentime resolution: VELO + tracking system Hadron identification: RICH system L0 Lepton and Hadron p T trigger: Calorimeter and muon system T. Nakada SLAC Summer Institute, July 2006 3
bb pair production kinematics b parton-1 parton-2 b b p b p b-b correlation b b b b Both b and b are in the spectrometer. No T. Nakada SLAC Summer Institute, July 2006 4
f pp @ LHC = 40 MHz simple first level trigger needed Single p T trigger for μ, e, h p L p p T p muon system: low track density e and h: calorimeter E T measurements T. Nakada SLAC Summer Institute, July 2006 5
p < p min p > p min However. p > p min muon: identification Fe hadron: energy resolution E /E 70%/ E central detector forward detector p p L > p min p p p T > p min p p p p T threshold can be set low: high b efficiency T. Nakada SLAC Summer Institute, July 2006 6
Momentum spectrum and decay distance for B mesons are larger in the forward region. average B decay distance in the detector ~1cm Good proper time resolution. T. Nakada SLAC Summer Institute, July 2006 7
2) Status of the Experiment CERN LHC IP8: LHCb pit Brazil, China, France, Germany, Italy, Netherlands, Poland, Romania, Russia, Spain, Switzerland, UK, Ukraine, USA 600 people, 75 MCHF T. Nakada SLAC Summer Institute, July 2006 8
LHC <L> ~ 2 10 32 (L nominal = 10 34 ), b = 500 μb ( inelastic = 80 mb), 10 12 bb/10 7 sec B u,d,s,c, b, b, and other b-hadrons T. Nakada SLAC Summer Institute, July 2006 9
LHC tunnel radiation protection wall electronics huts with readout electronics and CPU farm LHC tunnel Muon Calo RICH-2 OT/IT Magnet TT RICH-1 VELO <L> ~ 2 10 32 (L nominal = 10 34 ), b = 500 μb ( inelastic = 80 mb), 10 12 bb/10 7 sec B u,d,s,c, b, b, and other b-hadrons T. Nakada SLAC Summer Institute, July 2006 10
LHCb Spectrometer OT Muon System Magnet RICH1 VELO TT RICH2 Calo. System T. Nakada SLAC Summer Institute, July 2006 11
Beam pipe 10mrad stainless steel cone Al bellows Al exit window of VELO tank 25mrad Be cone 10mrad Be cone T. Nakada SLAC Summer Institute, July 2006 12
Magnet assembled, positioned, aligned, and field map measured - the field was measured with a precision of 3 10 4 fulfils the requirement - good symmetry between the two polarities: B/<B>~ 3 10 4 small fake P violation Magnet is now operational T. Nakada SLAC Summer Institute, July 2006 13
VErtex LOcator 300 μm Si sensor as close as 8mm from the beam collision point ~ 1m r-sensors 4 45 o sectors beam axis -sensors 10 o -20 o stereo angle 84 mm T. Nakada SLAC Summer Institute, July 2006 14
Si in secondary vacuum with the Roman pot technology Being lowered and Installed at final position vacuum vessel in its support T. Nakada SLAC Summer Institute, July 2006 15
Detector Module Impact parameter resolution 160 140 IP resolution [μm] 120 100 80 60 40 20 750 0 B decay tracks 500 250 0 0 0.5 1 1.5 2 2.5 3 3.5 4 1/p T [GeV/c] 1 T. Nakada SLAC Summer Institute, July 2006 16
Outer Tracker and Silicon Tracker ~1.4 1.2 m 2 Inner Tracker Outer Tracker Trigger Tracker Silicon Tracker T. Nakada SLAC Summer Institute, July 2006 17
Straw drift chambers Outer Tracker 40μm Kapton XC-160 + Laminated Kapton-Al connecting two small modules around the beam pipe All the detector module construction completed T. Nakada SLAC Summer Institute, July 2006 18
Module Support C-frame -prototype tested -all produced and delivered at CERN -ready for loading the modules OT support hanging structure installed T. Nakada SLAC Summer Institute, July 2006 19
Trigger Tracker ~1.4 1.2 m 2 Silicon Tracker Inner Tracker ~130 45 cm 2 500 μm Si Si ladder production in progress 410 μm Si 320 μm Si T. Nakada SLAC Summer Institute, July 2006 20
Typical event display: Red = measurements (hits) Blue = all reconstructed tracks T1 T2 T3 VELO TT Average # of tracks in b-events: 34 VELO, 33 long, 19 T tracks, 6 upstream, 14 downstream Total 106 reconstructed tracks ~ 20 to 50 hits assigned to each long track 98.7% correctly assigned long track efficiency ghost rate T. Nakada SLAC Summer Institute, July 2006 21
0.7 VELO + ST + OT + Magnet 0.6 0.5 Δp/p [%] 0.4 0.3 0.2 0.1 0 800 B decay tracks 600 400 200 0 0 20 40 60 80 100 120 140 p [GeV/c] momentum resolution Proper time resolution ~ 40 fs B s D s + T. Nakada SLAC Summer Institute, July 2006 22
RICH Two RICH with three radiators Aerogel RICH1 (25-300 mrad) C 4 F 10 CF 4 RICH2 (15-120 mrad) T. Nakada SLAC Summer Institute, July 2006 23
HPD Photodetectors RICH1 Spherical Mirrors RICH2 Central Tube Beam Pipe Flat Mirror Spherical Mirror Magnetic Shield Flat mirrors Support Structure Photon Funnel + Shielding Prototype mirror from CMA (600 x 600 mm 2 ) Gas Enclosure T. Nakada SLAC Summer Institute, July 2006 24
HPD 80mm 120mm 1024 pixel (500μm 500μm) detector and bump bonded pixel readout electronics. RICH1 RICH1 RICH2 T. Nakada SLAC Summer Institute, July 2006 25
RICH-2 transport to IP8 T. Nakada SLAC Summer Institute, July 2006 26
PID for B and B s KK reconstruction B s D s suppression with PID for B s D s K Comb. suppression with PID for B DK 0 T. Nakada SLAC Summer Institute, July 2006 27
Calorimeter System Ecal Shashlik 25X 0 Hcal Fe-Scintillator tile 5.6 SPD/PS Scintillator-Pb-Scintillator Production completed T. Nakada SLAC Summer Institute, July 2006 28
9.4% E E-cal measured in test beam (0.83±0.02)% 0.02)% (0.145GeV GeV)/E front E-cal installation completed T. Nakada SLAC Summer Institute, July 2006 29
PS/SPD fibre connections Hcal installation completed T. Nakada SLAC Summer Institute, July 2006 30
and being installed T. Nakada SLAC Summer Institute, July 2006 31
Muon System Projective readout based on MWPC s except 3-GEM at M1R1(high occupancy) MWPC production T. Nakada SLAC Summer Institute, July 2006 32
Infrastructure at the pit construction of the chamber mounting wall >50% completed Fe filter and electronics tower ready T. Nakada SLAC Summer Institute, July 2006 33
Current status of the pit (IP8) Muon filter electro. tower OT SPD/Preshower IT Ecal Hcal RICH-2 dipole VELO magnet RICH-1 T. Nakada SLAC Summer Institute, July 2006 34
Trigger and Online Calorimeter, Muon and Pile-up Level-0: medium p T trigger: 40 MHz 1 MHz All the detector data 1 MHz @ 30kB/event commercial components running HLT algorithms Switch CPU. CPU Readout Network Switch CPU. CPU Switch CPU. CPU data logging 2000 Hz storage device T. Nakada SLAC Summer Institute, July 2006 35
Level-0: Muon, Calorimeter (e, h,, 0 ), Pile-up veto, Decision Unit prototypes. Muon processor board Calo selection board Pile-up veto Decision Unit T. Nakada SLAC Summer Institute, July 2006 36
Level-0 efficiencies for offline selected events Hadron Muon ECal Signal efficiency ~50% ~85% ~70% Ouput Rate 700 khz 200 khz ~200 khz L0 setting Type Hadron Electron Photon 0 local 0 global Muon Di-muon p μ T Thresh (GeV) 3.6 2.8 2.6 4.5 4.0 1.1 1.3 T. Nakada SLAC Summer Institute, July 2006 37
Tell1: LHCb common readout board Force10 E1200 network switch CPU farm prototype Optical receiver card Giga-bit Ethernet transmitter card 350 boards ~1800 boxes 3600 CPU s T. Nakada SLAC Summer Institute, July 2006 38
CPU farm: 1800 boxes = 3600 CPU s Start with L0-info, VELO, TT, T and Muon look for events with medium p T tracks with large impact parameters high p T muon tracks di-muon high p T photon Reject events as soon as possible. Later include Calorimeters and RICH exclusive reconstruction of B decays semi-inclusive reconstruction of B decays exclusive D reconstruction etc. On tape: 200 Hz B exclusive, 1.8 khz D +di-muon+single-muon T. Nakada SLAC Summer Institute, July 2006 39
Computing C++ based LHCb complete software suite for simulation, reconstruction, analysis, alignment and calibration, and high level trigger are running under the uniform framework GAUDI LHCb computing model based on - reconstruction, pre-selection and analysis at Tier-1 - simulation at Tier-2 All the computing aspects are periodically tested through Data Challenges simulation and reconstruction jobs running at WLCG sites in DC2006 On going! T. Nakada SLAC Summer Institute, July 2006 40
Preparation for the first data In order to be ready for 1) pilot run @900 GeV in November 2007 2) first physics run @14 TeV in Spring 2008 we have Commissioning Task Force - Defining the mode of operation for data taking, and identifying, producing, implementing and testing all the tools necessary for this operation; - Coordinating the commissioning the sub-systems; - Preparing the detector for steady data taking, through global commissioning, including the pilot run Physics Planning Group - Optimizing physics output for a given running scenario and preparing necessary tools T. Nakada SLAC Summer Institute, July 2006 41
4) Conclusions LHCb expects to take B physics a significant step further than the B factories: - access to other b hadron species + high statistics - excellent vertexing and particle ID - flexible and efficient trigger, dedicated to B physics Many channels with different sensitivities to new physics Construction of the LHCb detector is advancing well Low luminosity (~10 32 ) required for the LHCb experiment will allow to exploit full physics potential from the beginning of the LHC operation, and we will be ready for the pilot run in 2007 and the start of physics exploitation in Spring 2008 T. Nakada SLAC Summer Institute, July 2006 42