July 13-25, 2000, Hanoi, Vietnam Aurelio Bay Institut de Physique des Hautes Energies Aurelio.bay@iphe.unil.ch

SM g b The Unitary Triangle t d b W (1-r)2+h2 Im ~ (1-r)2 + h2 r2+h2 from Dm: (1-r)2+h2 Im ~ (1-r)2 + h2 r2+h2 from BÆXu+ln B0 ~Vtd J/Y Ks B0 t ~Vub W W t B0 b g Re CP Asym ~ sin[2(b+fnew )] The Unitary Triangle

+ New FCNC + + b+fnew b+fnew (1-r)2+h2 + rnew d b ~ (1-r)2 + h2 from Dm: (1-r)2+h2 + rnew + + d b NEW FCNC ~ (1-r)2 + h2 r2+h2 = cte from BÆXu+ln + rnew Unchanged B0 t W t b+fnew NEW b+fnew

SM + New FCNC + g b+fnew The Unitary Triangle t d b W (1-r)2+h2 +rnew from Dm: (1-r)2+h2 +rnew + Im d b NEW FCNC ~ (1-r)2 + h2 r2+h2 from BÆXu+ln + rnew B0 J/Y Ks Unchanged B0 ~Vub t W W t B0 g b+fnew NEW Re CP Asym ~ sin(2(b+fnew)) The Unitary Triangle

g from Bd Æ D*-np+, D*+np-, etc. CP in BÆJ/Y Ks ~ 2(b + fnew) Bd Æ D*+ np vs Bd Æ D*+ np Bd Æ D*- np vs Bd Æ D*- np From 2(b + fnew) + g g Idem with Bs decays: compare the two g determinations (then combine them) 2 ( dg + fsnew ) from CP in Bs Æ J/y f 2 ( dg + fsnew ) - g from CP in Bs Æ Ds-K+, Ds+ K- g We want to measure g, we need to select hadronic decay channels, we want to study the Bs system, have K/p separation, access to Br < 10-7….

Rate(bb) = 105 sec-1 : 0.5% total inelastic LHCb overlook BABAR, BELLE, CLEO-III, CDF, D0, HERA-B will test CKM at the O(l3) level. LHCb is a second generation experiment for CP violation studies in the B and Bs meson systems. The goal is to obtain precise and overconstrained determination of CKM elements, including terms beyond O(l3). This will permit to detect deviations from the Standard Model description and thus to probe New Physics. Second generation means: High statistics is needed to study Bu,d,s decays with Br < 10-7 Excellent proper time resolution Excellent particle identification Efficient and flexible triggering scheme, including a selection on hadrons. High statistics can be obtained by LHCb because B production cross section at 14 TeV: LHCb running luminosity: fi sbb ≈ 500 mb 2 1032 cm-2 s-1 Rate(bb) = 105 sec-1 : 0.5% total inelastic

LHCb non-bending plane view Magnet dipole non-bending plane view LHC beams collide here Vertex Locator x z 20 m 10 m Open geometry with (quite) easy access to (almost) all components q Π[15, 300] mrad h Π[4.9, 1.9]

LHCb bending plane

Vertex Locator (VELO) s impact parameter [mm] Z 100 10 0.1 1 10 -20 80 cm toward spectrometer s impact parameter 100 10 [mm] 0.1 1 10 Pt [GeV] Z retract by 3 cm during beam setup 0 0.8 4 cm sz ≈ 40 mm resolution on interaction point • ≈ 200 mm Si single-side • R and f measuring planes • 220 kchannels, analogue R/O, S/N =15 Design work on front-end chip (DMILL and sub-micron technolgies) in progress prototype of R measuring 1/2 plane

RICH K–p separation > 3 s 1<p< 100 GeV/c pixel HPD Aerogel Gas CF4 Gas C4F10 Aerogel RICH K–p separation > 3 s 1<p< 100 GeV/c large aerogel rings small C4F10 CF4 rings

RICH R&D Photodetectors options: HPDs and multianode PMTs single photoelectron resolution QE = 17% @ 400 nm spatial resolution ~1 mm large area ~2.9 m2, active: ~ 70% Æ 325 kchan. binary readout B stray field up to 100 gauss radiation dose < 3kRad/year pedestal 1 p.e. 2 p.e. 3 p.e. 4 p.e. Pion beam: large rings in aerogel and small rings in C4F10 threshold DEP prototype pixel HPD

Other Systems Magnet: Warm dipole 4 Tm - 4.2 MW - 1450t TDR ok Tracker Inner: (40x60 cm2) triple GEM , Si 3 stations Outer: straw-tube drift chambers sp/p = 0.3 % [5 , 200] GeV/c s(MB->pp) =15 MeV/c2 s(MD->KKp) = 4 MeV/c2 Calorimeter (design completed) Pre-shower sandwich Pb - scintillators ECAL Shashlik type, 25 X0 HCAL Fe + scintillating tiles, 5.6l R/O by wave-length shifting fibers and PMTs MUON Resistive Plate Chambers (RPC) + Wire and Cathode Pad Chambers (WPC/CPC) for high rate regions

Joint Calorimeter Test HCAL Fe+scintillating tiles ECAL Shashlik Joint Calorimeter Test preshower 0 20 40 GeV ECAL resolution % 30 20 10 HCAL resolution % 0 50 100 150 200 GeV

LHCb Trigger Efficiency for reconstructed and correctly tagged events L0(%) L1(%) L2(%) Total(%)  e h all BdJ/(ee)KS + tag 17 63 17 72 42 81 24 BdJ/()KS + tag 87 6 16 88 50 81 36 BsDsK + tag 15 9 45 54 56 92 28 BdDK        Bd + tag 14 8 70 76 48 83 30 where the lepton trigger is important where the hadron trigger is important Tags considered (so far): muon or electron from other b-hadron b Æ lepton charged kaon from other b-hadron b Æ c Æ s Overall tag efficiency = 40% Overall mistag rate = 30%

Trigger System LHC: 40 MHz L0:1 MHz L1:40 KHz Output:200 Hz High PT muons Latency: 4 ms < 2 ms L0 decision unit L1 Trigger 3D reconstruction of secondary vertices L2+L3 Trigger Full event information High PT electrons High PT hadrons Pileup Veto B0 Æ p+ p- Running luminosity 2 x 1032 Inelastic pp interactions hadron trigger threshold ~30 % ~10%

Mass, decay time resolutions and particle ID Measurements of ms with a significance >5: up to psxs Bs-Bs oscillations with BsDs Dms = 30 ps-1  DsK Ds 5.2 5.3 5.4 5.5 GeV/c2 without RICH with RICH Bs  DsK separation from Bs  Ds Mass(DsK) sm = 11 MeV/c2 Ds DsK 5.2 5.3 5.4 5.5 5.6 GeV/c2

LHCb CP Sensitivities in 1 year Parameter Channels+c.c. No of events (1 year)  Bd 5k @P/T = 30°, |P/T|=0.200.02, =90° 2-5 Bd0  r  1k @ =50° 5 2+ Bd  D*(incl.) 260k @2+=0 12  BdJ/Ks 100k <0.6 -2 Bs DsK 2400 8(Dms=15ps-1) - 12  (45ps-1)  Bd  DK* 400 10  Bs  J/ 50k 0.6 Bs oscillations xs Bs  Ds 35k up to 75 (5s) Rare Decays Bs   11 s/b=3.5 Bd K0*  4500 s/b=16 Bd  K*  26k s/b=1 See yellow Book CERN 2000-004 !

LHCb schedule (and conclusion) 1998 Technical Proposal 1999 LHCb approved Magnet 2000 RICH, Calorimeters Outer Tracker Technical Design Reports Muon System 2001 Vertex Detector Inner Tracker 2002 L0 & L1 Trigger, DAQ Computing 2003 Magnet installation Detector and DAQ installation 2004 2005 LHCb ready for LHC « day one » and for many years of B physics at “nominal LHCb luminosity”