CIPANP2003 K. Honscheid Ohio State The Future of Flavor Physics at Hadron Colliders CIPANP 2003 K. Honscheid Ohio State University

CIPANP2003 K. Honscheid Ohio State B Physics Today CKM Picture okay CP Violation observed No conflict with SM V ud V us V ub V CKM =V cd V cs V cb V td V ts V tb sin(2  ) = /

CIPANP2003 K. Honscheid Ohio State Surprising B Physics YearItemTheory Prediction ~Value # B’s 1983  b Too small to be observed ~ < 0.1ps 1 ps2x B o -B o mixing Too small to see (~ < 1%) as m top is believed to be ~30 GeV 20%2x sin(2  ) No direct prediction, but consistent with other measurements 3/410 7  >10 11 b hadrons (including B s )

CIPANP2003 K. Honscheid Ohio State B Physics at Hadron Colliders Energy2 TeV14 TeV b cross section ~100  b~500  b c cross section ~1000  b~3500  b b fraction2x x10 -3 Inst. Luminosity2x10 32 >2x10 32 Bunch spacing132 ns (396 ns)25 ns Int./crossing ( ) Luminous region 30 cm5.3 cm TevatronLHC Large cross sections Triggering is an issue All b-hadrons produced (B, B s, B c, b-baryons)

CIPANP2003 K. Honscheid Ohio State Detector Requirements From F. Teubert Vertex, decay distance Momentum PID Neutrals ( ,  0 )

CIPANP2003 K. Honscheid Ohio State CDF and D0 CDF pioneered B physics at hadron collider. New for Run II TOF (Particle ID) Detached Vertex Trigger Improved tracking D0 enters B physics New for Run II Tracking Detached Vertex Trigger (soon)

CIPANP2003 K. Honscheid Ohio State n Acceptance  |  | < 2.5 n Particle ID  ATLAS v.limited  -K separation, ~0.8s from TRD n Di-lepton trigger n Vertexing wSpecial pixel B layer R~5cm n “Low” luminosity running wLumi cm -2 s -1 wOnly 30fb -1 (3 years) wSpecialist B triggers n BUT : DAQ Bandwidth only 100 evts/s to tape for ALL physics ATLAS Atlas and CMS From N. Harnew

CIPANP2003 K. Honscheid Ohio State Forward vs. Central Geometry b production angle  230  b 100  b Multi-purpose experiments require large solid angle coverage. Central Geometry (CDF, D0, Atlas, CMS) Dedicated B experiments can take advantage of Forward geometry (BTeV, LHCb)

CIPANP2003 K. Honscheid Ohio State LHCb Light n No tracking stations in magnet region n Reduced material budget n (fringe) magnetic field in tracking station(s)

CIPANP2003 K. Honscheid Ohio State The Importance of Particle ID Purity = 84% ; Efficiency = 90% B 0  h + h -  ~17 MeV For example: B->  +  -

CIPANP2003 K. Honscheid Ohio State The BTeV Detector Beam Line Pixel Detector Vacuum Vessel 60 pixel planes inside magnet  = 5-10  m Proper time resolution: 46 fs PbWO 4 EM Calorimeter CLEO/BaBar/BELLE-like performance in a hadron Collider environment!  ~ 5 MeV  ~ 3 MeV crystals 220 mm long, 28x28 mm 2 Detached Vertex Trigger Find the primary vertex Identify tracks which miss it Calculates the significance of detachment For EVERY crossing b,b/  b

CIPANP2003 K. Honscheid Ohio State Fully simulated bb event using Geant 3 incl. multiple scattering, hadronic interactions decays in flight Kalman fitter

CIPANP2003 K. Honscheid Ohio State Efficiencies and Tagging For a requirement of at least 2 tracks detached by more than 6 , we trigger on only 1% of the beam crossings and achieve the following trigger efficiencies for these states ( int. per crossing):   efficiency; D  Dilution or (N right -N wrong )/(N right +N wrong ) Effective tagging efficiency   D 2 Extensive study for BTeV uses Opposite sign K ± Jet Charge Same side  ± (for B o ) or K ± for (B s ) Leptons Conclusion:  D 2 (B o ) = 0.10,  D 2 (B s ) = 0.13 (difference due to same side tagging) Decay efficiency(%) Decay efficiency(%) B   +  - 63 B o  K +  - 63 B s  D s K 74 B o  J/  K s 50 B -  D o K - 70 B s  J/  K * 68 B -  K s  - 27 B o  K * 

CIPANP2003 K. Honscheid Ohio State The Physics Goals There is New Physics out there: Baryon Asymmetry of Universe & by Dark Matter Hierarchy problem Plethora of fundamental parameters … B Experiments at Hadron Colliders are well positioned to: Perform precision measurements of CKM Elements with small model dependence. Search for New Physics via CP phases Search for New Physics via Rare Decays Help interpret new results found elsewhere (LHC, neutrinos) Complete a broad program in heavy flavor physics Weak decay processes, B ’s, polarization, Dalitz plots, QCD… Semileptonic decays including  b b & c quark Production Structure: B(s) spetroscopy, b-baryon states B c decays

CIPANP2003 K. Honscheid Ohio State Part 1: Is the CKM Picture correct? Use different sets of measurements to define apex of triangle (adopted from Peskin) Also have  K (CP in K L system) Magnitudes B d mixing phase B s mixing phase Can also measure  via B -  D o K -,

CIPANP2003 K. Honscheid Ohio State Measuring   Using B o         A Dalitz Plot analysis gives both sin(2  ) and cos(2  ) ( Snyder & Quinn) Measured branching ratios are: B (B       = ~10 -5 B (B      +      = ~3x10 -5 B (B       <0.5x10 -5 Snyder & Quinn showed that tagged events are sufficient Not easy to measure  0 reconstruction Not easy to analyze 9 parameter likelihood fit Slow  0 ’s Nearly empty (  polarization) Dalitz Plot for B o 

CIPANP2003 K. Honscheid Ohio State Yields for B o  Based 9.9x10 6 background events B o  +  events, S/B = 4.1 B o  o  o 780 events, S/B = 0.3   oo Background Signal m B (GeV) BoooBooo

CIPANP2003 K. Honscheid Ohio State Our Estimate of Accuracy on  Geant simulation of B o  (for 1.4x10 7 s) Example: 1000 B o  signal + backgrounds With input  =77.3 o minimum  2 non-resonant non-  bkgrd resonant non-  bkgrd  (gen) R res R non  (recon)  77.3 o o 1.6 o 77.3 o o 1.8 o 93.0 o o 1.9 o 93.0 o o 2.1 o o o 3.9 o o o 4.3 o

CIPANP2003 K. Honscheid Ohio State B s Mixing (V td /V ts )  m s (~x s ) =  ·C where C can be calculated inside the S. M. CDF sensitive to x s ~ 30  : B s ->  seen Expect  ~ 2% after Run II BTeV reaches sensitivity to x s of 80 in 3.2 years

CIPANP2003 K. Honscheid Ohio State One of several ways to determine   B s  D s K  D s  mass (GeV)  ~ 6.5 MeV/c 2  = 168  m  = 418  m B s vtx resolution (mm) D s vtx resolution (mm) ± Theoretically clean, BR ~ 10 -4

CIPANP2003 K. Honscheid Ohio State Needed: Hadronic trigger K/  separation Good proper time resolution Sensitivity depends upon relative amplitudes strong phase difference values of ,  m s  s  s For  m s =20 ps –1 :  10 o For  m s =30 ps –1 :  12 o In one year: 8k B s  D s  K  reconstructed events    from B s  D - s K +, D + s K -  (II)  From the measurement of 4 time-dependent asymmetries one gets    same order tree level amplitudes (  3 ) : large asymmetries, NP contributes unlikely From M. Musy

CIPANP2003 K. Honscheid Ohio State Measuring  In the SM the phases and magnitudes are correlated:  |V us | = ±  is the phase of V ts -> B s Mixing Good: B s -> J/   plus non-trivial angular analysis Better: B s -> CP eigenstate such as B s  J/      Silva & Wolfenstein (hep-ph/ ) Aleksan, Kayser & London

CIPANP2003 K. Honscheid Ohio State Measuring  II BTeV can reconstruct  and  ’ Yield in one year B s  J/  2,800 events with S/B = 15 B s  J/  9,800 events with S/B = 30 Error on sin(2  = With  ~ 2 o a precision measurement will require a few years.

CIPANP2003 K. Honscheid Ohio State Physics Reach (CKM) in 10 7 s Reaction B (B) (x10 -6 ) # of Events S/B Parameter Error or (Value) B s  D s K  -  8 o B s  D s  ,000 3 x s (75) B o  J/  K S J/  +  , sin(2  ) B o  J/  K o, K o    cos(2  ) ~0.5 B -  D o (K +  - ) K B -  D o (K + K - ) K ,000>10  13 o B s  J/  330 2, B s  J/  670 9, sin(2  Bo+-Bo+- 28 5, BoooBooo  ~4 o Reaction B (B) (x10 -6 ) # of Events S/B Parameter Error B-KS -B-KS  ,600 1 <4 o + BoK+-BoK+ ,  Theory err. Bo+-Bo+ ,600 3Asymmetry B o  K + K , Asymmetry 0.020

CIPANP2003 K. Honscheid Ohio State LHCb preliminary study  (pp  B c ) ~300 nb  10 9 B c / year B c  J /  BR ~10 -2 )  ~ 2% 12k events/year Background from B  J /  X and prompt J /  reduced cutting on the distance between primary vertex and B c vertex B c mesons CDF: m Bc = 6.4 +/- 0.4 GeV t Bc ~ 0.5 ps BTeV/LHCb: Precision measurements of mass, lifetime Search for CPV in B c -> J/  D + or B c -> D s D  LHCb acceptance ~30% M( J /  GeV/c 2 p (GeV)

CIPANP2003 K. Honscheid Ohio State Part II: Search for New Physics For a nice overview see: S. Stone “BTeV Physics” at

CIPANP2003 K. Honscheid Ohio State First Example: Supersymmetry Supersymmetry: In general 80 constants & 43 phases MSSM: 2 phases (Nir, hep-ph/ ) New Physics in B o mixing:  D, B o decay:  A, D o mixing:  K  ProcessQuantity SMNew Physics B o  J/  K s CP asym sin(2  )sin2(  D ) BoKsBoKs CP asym sin(2  )sin2(  D  A ) DoK-+DoK-+ CP asym 0 ~sin(  K  ) New Physics Difference  NP

CIPANP2003 K. Honscheid Ohio State Rare b Decays Search for New Physics in Loop diagrams New fermion like objects in addition to t, c or u New Gauge-like objects in addition to W, Z or g Inclusive Rare Decays including b  s  b  d  b  s +  Exclusive Rare Decays such as B    B  K* +  Dalitz plot & polarization   + - B o  K* 

CIPANP2003 K. Honscheid Ohio State Yield, S/B for Rare b Decays Reaction B (10 -6 ) Signal S/BPhysics B o  K* o  +  Polarization; Rate B-K-+-B-K-+ Rate bs+-bs+ Rate; Wilson coefficents

CIPANP2003 K. Honscheid Ohio State BTeV data compared to Burdman et al calculation Dilepton invariant mass distributions, forward-backward asymmetry discriminate among the SM and various supersymmetric theories. (Ali, Lunghi, Greub & Hiller, hep-ph/ ) One year for K* + -, enough to determine if New Physics is present Polarization in B o  K* o  +  - Ali et. al, hep-ph/

CIPANP2003 K. Honscheid Ohio State Search also for B d 0     Standard Model BR ~ 1x B s 0     Standard Model BR ~ 4x Here the General Purpose Detectors have an advantage : high p T di-muon triggering at high (1x10 34 ) luminosity. CMS : 100 fb -1 (10 7 s at cm -2 s -1 ) ~26 signal events 6.4 events background Muon trigger : 2  ’s with pT > 4 GeV  < 2.4 Rare Leptonic Decays

CIPANP2003 K. Honscheid Ohio State Another Example: Extra Dimensions Aranda & Lorenzo Diaz-Cruz, “Flavor Symmetries in Extra Dimensions” (hep-ph/ ) (Buras et al. hep-ph/ ) Extra spatial dimension is compactified at scale 1/R = 250 GeV on up No effect on |V ub /V cb |,  M d /  M s, sin(2  ) –8% – % |V td |  B s -> 

CIPANP2003 K. Honscheid Ohio State Summary Heavy quark physics at hadron colliders provides a unique opportunity to measure fundamental parameters of the Standard Model with no or only small model dependence discover new physics in CP violating amplitudes or rare decays. interpret new phenomena found elsewhere (e.g. LHC) Some scenarios are clear others will be a surprise This program requires a general purpose B detector like BTeV and LHCb with an efficient, unbiased trigger and a high performance DAQ a superb charged particle tracking system good particle identification excellent photon detection

CIPANP2003 K. Honscheid Ohio State Additional Transparencies from BTeV and LHCb Studies

CIPANP2003 K. Honscheid Ohio State   from B s  J/    from B s  J/   In SM  S     Sensitive to New Physics effects in the B s -B s system In one year: 109 k events B s  J/      19 k events B s  J/  e + e   J/  is not CP eigenstate: needs fit to angular distributions of decay final states as a function of proper time Assuming  m s =20 ps –1 :  2 o   36±1 fs From M. Musy

CIPANP2003 K. Honscheid Ohio State Current status of LHCb Physics Reach in 1 year (2fb –1 ) ChannelYield Precision *  B d  J /  K s 119 k  0.6 o  B s  D s K B d  , B s  KK 8 k 27 k, 35 k  10 o  3 o  Bd  Bd   27 k  5 o - 10 o  B s  J /  128 k  2 o |V td /V ts  B s  D s  72 k  m s up to 58 ps  rare decaysB d  K   20 k All numbers will be updated together with more channels in the re-optimization LHCb TDR (September 2003) From M. Musy

CIPANP2003 K. Honscheid Ohio State A simplified trigger comparison From U. Egede

CIPANP2003 K. Honscheid Ohio State Unitarity Triangles B d 0     B d 0    B d 0  DK *0 B S 0  D S K B d 0  D*  B S 0  D S  B d 0  J/  K S 0 B S 0  J/  From N. Harnew 