StatusStatusStatus ofofof thethethe LHCbLHCbLHCb ExperimentExperimentExperiment
o Introduction o Detector Status – VELO – RICH – ECAL – Trigger o Physics o Conclusions
Beauty 2000 Sea of Galilee Franz Muheim 13. 9. 2000 University of Edinburgh DedicationDedication
Tom Ypsilantis o conceived RICH detectors 1928 - 2000 in 1977 (with J. Seguinot) o a founding member of LHCb, totally dedicated to the RICH project o a colleague always eager to discuss new ideas o was a good friend for many of us o He will be missed
Sea of Galilee, 13. 9. 2000 Beauty 2000 2 IntroductionIntroduction o CPV only observed in UnitarityTrianglesUnitarityTriangles neutral kaon system Vud Vub* + Vcd Vcb* + Vtd Vtb* = 0 – theoretical uncertainties o Standard Model – 3 generation CKM matrix allows for CPV if h¹0 – predicts large CPV asymmetries for B mesons o No real understanding Vud* Vtd + Vus* Vts + Vub* Vtb = 0 – Baryogenesis: additional source of CPV needed arg Vub = -g arg Vtd = -b – why is strong CPV small? arg Vts = p+ dg Ô New physics around the corner? Sea of Galilee, 13. 9. 2000 Beauty 2000 3 inin BB MesonMeson SystemSystem o Ideal to search for new physics Peskin, EPS 1999 o SM makes accurate predictions – precision tests o CPV in many decays – consistency o Examples – Vub & BB-mixing – sin 2b & sin 2a
– g & dg with Bs mesons
– compare to kaon sector eK & K-> pnn o Can extract parameters of SM and new physics Sea of Galilee, 13. 9. 2000 Beauty 2000 4 LargeLarge HadronHadron ColliderCollider o By 2005: BABAR, BELLE, CLEO-III, CDF, D0, HERA-B Ô 1st test of CKM matrix (r,h) vs sin 2b o LHCb is a 2nd generation experiment Ô precision measurements of CP overconstrain CKM elements LHCLHC Ô large statistics, Bs mesons o LHC is the most intensive source of
B mesons (Bd, Bu, Bs, Bc)
– sbb = 500 mb sinelastic = 80 mb 32 -2 -1 – Luminosity
Sea of Galilee, 13. 9. 2000 Beauty 2000 5 LHCbLHCb ExperimentExperiment o LHCb Detector bbbb angularangular productionproduction – forward single arm spectrometer o Challenges – Trigger: leptonic and hadronic final
states (eg Bd -> pp) – Particle Identification: p-K separation 1 GeV < p < 150 GeV – Vertexing: proper time resolution
43 fs Bs -> Dsp(K) 30 fs Bs -> J/y f
Sea of Galilee, 13. 9. 2000 Beauty 2000 6 LHCbLHCb ExperimentExperiment
o Acceptance 10 - 300 (250) mrad (non)-bending plane
o Open geometry easy access
Sea of Galilee, 13. 9. 2000 Beauty 2000 7 LHCbLHCb ExperimentExperiment
o Vertex o Inner Tracker o Outer Tracker o RICH1 o RICH2 o Calorimeters ECAL HCAL o Muon Detector
Sea of Galilee, 13. 9. 2000 Beauty 2000 8 LHCbLHCb SubsystemsSubsystems SystemSystem TechnologyTechnology o Magnet warm o Vertex Locator r-phi Si strip detectos o Inner Tracker All Si strips or Si / Triple GEM o Outer Tracker1 Straw tube drift chambers o RICH HPD baseline/ MaPMT backup o Calorimeters Preshower: Scintillator/Pb/scint. ECAL: Shashlik, HCAL: Fe-scint. tile o Muons2 MWPC & RPC - single or double gap o Trigger L0 (hardware), L1 (vertex), L2, L3 o Computing3 OO & GAUDI, LHC GRID See separate talks by 1) B. Hommels, 2) E. Santovetti, 3) G. Corti Sea of Galilee, 13. 9. 2000 Beauty 2000 9 LHCbLHCb MilestonesMilestones o Aug 1995: LHCb Letter of Intent o Feb 1998: Technical Proposal o Sep 1998: Approval of TP o 1999 - 2001: Technology choices o Jan 2000: 1st Technical Design Report (TDR) - Magnet o 2000 - 2002 remaining TDRs o now - July 2004: Construction phase o July 2005: 1st beam
Sea of Galilee, 13. 9. 2000 Beauty 2000 10 LHCbLHCb TDRTDR SummarySummary
o Magnet TDR approved April 2000 o Vertex Locator TDR April 2001 o Inner Tracker TDR Sept 2001 o Outer Tracker TDR March 2001 o RICH TDR submitted 7. Sep 2000 o Calorimeters TDR submitted 6. Sep 2000 o Muons TDR Jan 2001 o Trigger TDR Jan 2002 o Computing TDR July 2002
Sea of Galilee, 13. 9. 2000 Beauty 2000 11 MagnetMagnet
o Properties: – Normal conducting (Al) – òBdl = 4Tm – Power 4.2 MW – Yoke 1450 t o TDR – submitted: Jan 2000 – recommended (LHCC) approved: April 2000 (Research Board) o Call for tender – now
Sea of Galilee, 13. 9. 2000 Beauty 2000 12 VertexVertex LocatorLocator
VELOVELO DesignDesign o Si strip detectors p-n, n-n, single sided, double metal read-out 220 mm thick, 1800 wedges o Optimized for Level 1 trigger (L1) Ô Alternate r and phi strip detectors varying strip pitch 20 - 40 mm in r o Detector halves retracted by Si Strip Layout ± 30 mm in y during injection radial phi Ô 8 mm from beam during physics o Radiation damage Ô may replace detectors after a few years
Sea of Galilee, 13. 9. 2000 Beauty 2000 13 VELOVELO DesignDesign
OptimisationOptimisation Toblerone RF shield o Use Liverpool MAP farm (300 Linux PCs) – 3.5 Million events – optimize # of stations, positions, outer & inner radii o 25 stations, mounted in “toblerone” RF shields – 220 k channels – 9.5 hits/ track o Proper time resolution
– st = 43 fs Bs -> Dsp
– sensitive up to xs ~ 75 (1 year)
Sea of Galilee, 13. 9. 2000 Beauty 2000 14 ElectronicsElectronics && MechanicsMechanics
ElectronicsElectronics VertexVertex tanktank o Analogue read-out o Front-end chip design – sub micron - BEETLE – DMILL - SCTA128_VELO o ODE prototype – Testbeam
Sea of Galilee, 13. 9. 2000 Beauty 2000 15 VELOVELO TestsTests o Testbeam – irradiated prototypes Setup – cluster finding efficiency 200 mm p-n “Micron” – resolution – signal shape
Sea of Galilee, 13. 9. 2000 Beauty 2000 16 VELOVELO SummarySummary o Geometry – smallest pitch where most important for impact parameter resolution, at inner radius: “pixels” of 20 x 6300 mm2 – optimum for L1 trigger – constant occupancy < 5 x 10-3 o Thin detectors – read out at outer rim – minimize multiple scattering – S/N ~ 15 sufficient for L1 trigger o Number of readout channels – 220 k reflects in cost DesignDesign CriteriaCriteria optimum for vertexing in LHCb
Sea of Galilee, 13. 9. 2000 Beauty 2000 17 ParticleParticle IdentificationIdentification o LCHb needs excellent charged particle identification 0 m ± o e.g. Bs -> Ds K sensitive to CP angle g å fp- å K+K- 0 m ± Cabibbo suppressed wrt to Bs -> Ds p final state: 3 kaons o Kaon tagging for b production flavour o Large momentum range 1 < p < 150 GeV RICHRICH
Sea of Galilee, 13. 9. 2000 Beauty 2000 18 RICHRICH RingRing ImagingImaging CherenkovCherenkov DetectorsDetectors
RICH1 RICH2 o Acceptance Photo detectors – 300 mrad RICH 1 – 120 mrad RICH 2 o Radiators / thresholds – Aerogel C4F10 CF4 p 0.6 2.6 4.4 GeV K 2.0 9.3 15.6 GeV
Sea of Galilee, 13. 9. 2000 Beauty 2000 19 PhotoPhoto DetectorsDetectors C F Aerogel 2 4 10 o Photo detector area: 2.9 m small rings large rings o Single photon sensitivity: 200 - 600 nm, quantum efficiency>20% o Good granularity: ~ 2.5 x 2.5 mm2 o Large active area fraction: ³ 73% o LHC speed read-out electronics: 40 MHz o LHCb environment: magnetic CF4 fields, charged particles
HPDHPD oror MAPMTMAPMT
Sea of Galilee, 13. 9. 2000 Beauty 2000 20 HybridHybrid PhotoPhoto DiodesDiodes
PixelPixel HPDHPD (baseline)(baseline) o Quartz window, thin S20 photo cathode òQE dE = 0.77 eV -20 kV o 32 x 32 Si pixel array: 500 mm o Cross-focusing optics – demagnification ~ 5 – 50 mm point-spread function – 20 kV operating voltage o Encapsulated binary electronics o Tube, encapsulation: DEP o Pixel sensor: CERN 6161 pixelpixel HPDHPD
o Existing prototype F = 80 mm external read-out Sea of Galilee, 13. 9. 2000 Beauty 2000 21 HPDHPD R&DR&D ResultsResults TestbeamTestbeam o Testbeam Setup – RICH 1 prototype – 3 HPDs o Figure of merit -1 – N0 » 225 - 250 cm
LEDLED
Spectrum
Sea of Galilee, 13. 9. 2000 Beauty 2000 22 HPDHPD ElectronicsElectronics PixelPixel chipchip
Occupancy ~3 % RICH 1 < 1% RICH 2
o ALICE / LHCb
50 mm o pixel size 50 mm x 425 mm o 8 pixels = 1 LHCb unit o 40 MHz read-out clock o in production (IBM) o Bump bonding: chip-sensor
Sea of Galilee, 13. 9. 2000 Beauty 2000 23 MAPMTMAPMT (backup)(backup) MultianodeMultianode PhotoPhoto MultiplierMultiplier TubeTube
o 8x8 dynode chains, pixel 2x2 mm2 o Gain: 3.105 at 800 V o UV glass window Bialkali photo cathode, QE = 22% at l = 380 nm
o MAPMT active area fraction: 38% (includes pixel gap) o Increase with quartz lens with one flat and one curved surface to 85%
Sea of Galilee, 13. 9. 2000 Beauty 2000 24 MAPMTMAPMT R&DR&D ResultsResults 3x33x3 ClusterCluster TestTest
o Beam test – RICH 1 Prototype o Observe in data . – CF4 @ 700 mbar 6.51 ± 0.34 p.e o Expect from simulation o 40 MHz Read-out: 6.21 p.e. APVm chip Sea of Galilee, 13. 9. 2000 Beauty 2000 25 RICHRICH PerformancePerformance o Simulation p-K separation – based on measured test beam HPD data – global pattern recognition – background photons included o # of detected photons – 7 Aerogel 33 C4F10 18 CF4 o Angular resolution [mrad] – 2.00 Aerogel 1.45 C4F10 0.58 CF4
Sea of Galilee, 13. 9. 2000 Beauty 2000 26 - + BBd ->-> pp pp
o sensitive to CKM angle a
o Adir and Amix depend also on |P/T| and strong phase d 0 0 o sa ~ 2 - 5 in 1 year – a dependent Tree T Penguin P – if |P/T| from elsewhere o Backgrounds have
Sea of Galilee, 13. 9. 2000 Beauty 2000 27 m ± BBs ->-> DDs KK
o Both diagrams of O(l3) Ô expect large o Rate asymmetries measure angle g-2dg o Expect 2400 events in 1 year of data taking Ô s(g-2dg) = 60 .. 140
Sea of Galilee, 13. 9. 2000 Beauty 2000 28 RICHRICH ConstructionConstruction RICHRICH 11 Kapton Seal
14% X0
Photo detectors Mirrors
Sea of Galilee, 13. 9. 2000 Beauty 2000 29 RICHRICH ConstructionConstruction IIII RICHRICH 22 o Submitted 7.9. 2000
Mirrors Side view
Top view
12.4% X0
Photo detectors
Sea of Galilee, 13. 9. 2000 Beauty 2000 30 CalorimetersCalorimeters
0 o L0 trigger - high pT hadrons, electrons, photons, p o electron, photon, p0 particle identification
ECALECAL HCALHCAL o Shashlik Pb/scintillator tiles, o Fe/ scintillator tiles,
l shifting fibres, PMT, 25 X0 l-shifting fibres, PMT, 5.6 l
50 m2
Sea of Galilee, 13. 9. 2000 Beauty 2000 31 ScintillatorScintillator // ll--ShifterShifter o Radiation – Inner most module 0.25 Mrad/year Dose e.m. o Extensive R&D – irradiation up to 5 Mrad hadronic – annealing for 175 h Scintillator l - shifter Resolution
Sea of Galilee, 13. 9. 2000 Beauty 2000 32 SPDSPD // PreshowerPreshower o Scintillator Preshower Scintillator Pad Detector Pads/ Pb 2X0 / PS Scintillator e-p separation o improved ECAL E resolution o l-shifting fibres read-out by MAPMTS Fibre/MAPMT optical coupling
o electron - photon separation, L0 trigger
Sea of Galilee, 13. 9. 2000 Beauty 2000 33 ECALECAL PerformancePerformance
s (E) 10% JointJoint CalorimeterCalorimeter TestTest = Å1.5% E E
Energy resolution Preshower Testbeam
ECAL HCAL
o HERA-B ECAL with similar design works well: p0 and h peak
Sea of Galilee, 13. 9. 2000 Beauty 2000 34 HCALHCAL PerformancePerformance
Testbeam 50 GeV Energy s (E) 80% pions = Å5% resolution E E
o Since TP: HCAL length shortened 7.3 l to 5.6 l – tiny effect on resolution o HCAL design- similar to ATLAS tile calorimeter
Sea of Galilee, 13. 9. 2000 Beauty 2000 35 CalorimeterCalorimeter ConstructionConstruction
o TDR submitted o Construction starts 2001
HCALHCAL modulemodule ECALECAL
Sea of Galilee, 13. 9. 2000 Beauty 2000 36 Front-EndFront-End ElectronicsElectronics
F/E chip amplifier integrator
12 bit ADC
FPGA pedestal subtraction
o Radiation hard: single event upsets L0 pipeline, derandomizer Sea of Galilee, 13. 9. 2000 Beauty 2000 37 TriggerTrigger SystemSystem
o Luminosity – bunch crossings with one pp interaction – radiation damage, occupancy, pile-up 32 -2 -1 –
– 40 MHz interaction rate, sinel / sbb =160 – bb rate 105 s-1, low interesting branching fractions, eg. B(B®pp) = 5 x 10-6 o Multilevel L0: Hardware L1: Vertex L2 & L3: Full event
Sea of Galilee, 13. 9. 2000 Beauty 2000 38 TriggersTriggers
LevelLevel 00 1 MHz o suppression x 40 latency: 4 ms o high pT muons Muon 0 o high pT electrons, photons, p ECAL Hardware o high pT hadrons E&HCAL o Pile-up veto, Interaction rate 12.3 MHz
L1L1 VertexVertex triggertrigger 40 kHz LevelLevel 22 && 33 o suppression x 25, latency: 500 ms o L2: vertexing with all o 1) track finding with r strips tracking systems 2) primary vertex o L3: full event 3) secondary tracks information 4) use phi strips - 3d vertices DAQ: 200 Hz 5) secondary vertices Sea of Galilee, 13. 9. 2000 Beauty 2000 39 TriggerTrigger EfficienciesEfficiencies
L0(%) L1(%) L2(%) Total(%) m e h all
Bd®J/y(ee)KS + tag 17 63 17 72 42 81 24 Bd®J/y(mm)KS + tag 87 6 16 88 50 81 36 Bs®DsK + tag 15 9 45 54 56 92 28 * Bd®DK + tag 8 3 31 37 59 95 21 + - Bd®p p + tag 14 8 70 76 48 83 30 o Trigger efficiencies are ~ 30 % o hadron trigger is important o Tagging: efficiency 40 %, mistag rate: 30 % – muon or electron from other B – charge kaon from other B
Sea of Galilee, 13. 9. 2000 Beauty 2000 40 TriggerTrigger StrategyStrategy o Multi level, Flexibility o Event Generator – not rely on single – Updated Pythia model and detector structure functions o Large change for charged o Stability, Robustness multiplicities compared to TP – running conditions
Multiplicity
Vary L0 thresholds
o Small effect on L0 performance
Sea of Galilee, 13. 9. 2000 Beauty 2000 41 - + BBd ->-> rr pp o Sensitive to angle a o 1300 events / year o Time dependent analysis of Dalitz plot allows measure – a, tree and penguin amplitudes
0 0 sa ~ 3 - 6 in 1 year
Sea of Galilee, 13. 9. 2000 Beauty 2000 42 *m ± BBd ->-> DD pp o Sensitive to angle -2b-g theoretically clean D* mass peak o Asymmetry tiny, but large BR o hadron trigger o 80 k exclusive events 260 k inclusive D*p events
Sensitivity
s2b+g
Will add *m ± Bd -> D a1 360 k events
Sea of Galilee, 13. 9. 2000 Beauty 2000 43 NewNew MethodsMethods o New strategies for measuring CKM angles - direct o combine Bd -> pK - charged and neutral B to extract g 0 0 – sg ~ 2 - 7 ambiguous solutions o combine Bs ->KK and Bd -> pp 0 – sg ~ 4 b known, U-spin – LHCb RICH at its best + - o combine Bd,s ->D d,s D d,s – O(100k) events per year 0 – sg ~ a few o Overconstrain CP angles a, b, g, and dg Sea of Galilee, 13. 9. 2000 Beauty 2000 44 RareRare DecaysDecays
+ - o Bs -> m m – Standard Model branching ratio: 3.7 x 10-9 ideal to search for new physics - FCNC – Expected signal (bkgd) : 11 (3.3) 1 year + - o Bd -> K*m m – Standard Model branching ratio: 1.5 x 10-6 dimuon mass spectrum, forward-backward asymmetry + - – combine with Bd -> r m m |Vts/Vtd| – Expected signal (bkgd): 22400 (1400) 1 year o Bd -> K*g – Standard Model branching ratio: 5 x 10-5 search for new physics in CPV asymmetry O(1%) in SM – Expected signal: 26000 1 year
Sea of Galilee, 13. 9. 2000 Beauty 2000 45 LHCbLHCb CPCP SensitivitiesSensitivities
Parameter Channels Evts/year s(1 year) LHCb feature
2(b+g) Bd®pp 4900 D|P/T| = 0 2°-5° PID, hadron trigger
Bd®rp ~1300 3°-6° PID, hadron trigger * 2b+g Bd ® D p 340000 > 11° PID, hadron trigger b Bd®J/yKs 37000 0.6° g-2dg Bs ®DsK 2400 6°-14° PID, hadron trigger, st * g Bd ® DK 400 10° PID, hadron trigger dg Bs ® J/yf 44000 0.6° st Bs oscillations xs Bs ® Dsp 120000 up to 75 hadron trigger, st Rare Decays -9 BR Bs ® mm <2´10 st * Bd ® K mm 22400 PID Sea of Galilee, 13. 9. 2000 Beauty 2000 46 ConclusionsConclusions o LHCb is progressing rapidly since Technical Proposal – Major technology choices made, e.g. – Magnet normal conductive coil – RICH pixel HPD baseline o Technical Design Reports – Magnet approved, RICH & ECAL submitted – other subsystems on track in this talk: Vertex o Trigger – robustness demonstrated, optimum luminosity, tuneable Ô take data from start of LHC & long physics programme o Physics performance studies extended o Construction phase starts now
Sea of Galilee, 13. 9. 2000 Beauty 2000 47