The Future of Flavor Physics at Hadron Colliders

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

B Physics Today CKM Picture okay VCKM = Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb CP Violation observed sin(2 b) = 0. 734 +/- 0. 054 No conflict with SM CIPANP 2003 K. Honscheid Ohio State

Surprising B Physics Year Item 1983 tb 1987 2001 Theory Prediction ~Value # B’s Too small to be observed ~ < 0. 1 ps 1 ps 2 x 104 Bo-Bo mixing Too small to see (~ < 1%) as mtop is believed to be ~30 Ge. V 20% 2 x 105 sin(2 b) No direct prediction, but consistent with other measurements 3/4 107 a, b, g >1011 b hadrons (including Bs) CIPANP 2003 K. Honscheid Ohio State

B Physics at Hadron Colliders Energy b cross section c cross section b fraction Inst. Luminosity Bunch spacing Int. /crossing Luminous region Tevatron LHC 2 Te. V ~100 mb ~1000 mb 2 x 10 -3 2 x 1032 132 ns (396 ns) <2> (<6>) 30 cm 14 Te. V ~500 mb ~3500 mb 6 x 10 -3 >2 x 1032 25 ns <1> 5. 3 cm Large cross sections Triggering is an issue All b-hadrons produced (B, Bs, Bc, b-baryons) CIPANP 2003 K. Honscheid Ohio State

Detector Requirements CIPANP 2003 K. Honscheid Ohio State • Vertex, decay distance • Momentum • PID • Neutrals (g, p 0) From F. Teubert

CDF and D 0 CDF pioneered B physics at hadron collider. New for Run II TOF (Particle ID) Detached Vertex Trigger Improved tracking D 0 enters B physics New for Run II Tracking Detached Vertex Trigger (soon) CIPANP 2003 K. Honscheid Ohio State

Atlas and CMS n n n CIPANP 2003 K. Honscheid Ohio State Acceptance w |h| < 2. 5 Particle ID w ATLAS v. limited p-K separation, ~0. 8 s from TRD Di-lepton trigger Vertexing w Special pixel B layer R~5 cm “Low” luminosity running w Lumi 1033 cm-2 s-1 w Only 30 fb-1 (3 years) w Specialist B triggers BUT : DAQ Bandwidth only 100 evts/s to tape for ALL physics ATLAS From N. Harnew

Forward vs. Central Geometry Multi-purpose experiments require large solid angle coverage. Central Geometry (CDF, D 0, Atlas, CMS) Dedicated B experiments can take advantage of Forward geometry (BTe. V, LHCb) 100 mb 230 mb bg bp rod CIPANP 2003 K. Honscheid Ohio State uc tio na ng le ngle bp tion a c u d o r

LHCb Light n n n CIPANP 2003 K. Honscheid Ohio State No tracking stations in magnet region Reduced material budget (fringe) magnetic field in tracking station(s)

The Importance of Particle ID For example: B-> p+p- B 0 h+hs ~17 Me. V Purity = 84% ; Efficiency = 90% CIPANP 2003 K. Honscheid Ohio State

The BTe. V Detector Pixel Detector Detached Vertex Trigger Vacuum Vessel • Find the primary vertex Pb. WO Calorimeter 4 EM • Identify tracks which miss it • Calculates the significance of detachment • For EVERY crossing 10500 crystals 220 mm long, 28 x 28 mm 2 Beam Line b, b/sb s(h->gg) ~ 5 Me. V Proper time resolution: 46 fs s(p->gg) ~ 3 Me. V CIPANP 2003 K. Honscheid Ohio State CLEO/Ba. Bar/BELLE-like performance in a hadron Collider environment! • 60 pixel planes • inside magnet • s = 5 -10 mm

Fully simulated bb event using Geant 3 • incl. multiple scattering, hadronic interactions • decays in flight • Kalman fitter CIPANP 2003 K. Honscheid Ohio State

Efficiencies and Tagging For a requirement of at least 2 tracks detached by more than 6 s, we trigger on only 1% of the beam crossings and achieve the following trigger efficiencies for these states (<2> int. per crossing): Decay efficiency(%) B p+ p 63 Bs Ds. K 74 B - Do K 70 B- Ksp 27 CIPANP 2003 K. Honscheid Ohio State Decay efficiency(%) B o K+ p 63 Bo J/y Ks 50 Bs J/y. K* 68 B o K* g 40 e efficiency; D Dilution or (Nright-Nwrong)/(Nright+Nwrong) Effective tagging efficiency e. D 2 Extensive study for BTe. V uses Opposite sign K± Jet Charge Same side p± (for Bo) or K± for (Bs) Leptons Conclusion: e. D 2 (Bo) = 0. 10, e. D 2 (Bs) = 0. 13 (difference due to same side tagging)

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 Lb b & c quark Production Structure: B(s) spetroscopy, b-baryon states Bc decays CIPANP 2003 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 e. K (CP in KL system) Bd mixing phase Magnitudes Bs mixing phase Can also measure g via B- Do. K- , CIPANP 2003 K. Honscheid Ohio State

Measuring a Using Bo rp p p po A Dalitz Plot analysis gives both sin(2 a) and cos(2 a) (Snyder & Quinn) Measured branching ratios are: B(B- rop-) Nearly empty (r polarization) ~10 -5 = B(Bo r-p+ + r+p-) = ~3 x 10 -5 B(Bo ropo) <0. 5 x 10 -5 Snyder & Quinn showed that 1000 -2000 tagged events are sufficient Not easy to measure p 0 reconstruction Not easy to analyze 9 parameter likelihood fit CIPANP 2003 K. Honscheid Ohio State Slow p 0’s Dalitz Plot for Bo rp

Yields for Bo rp Based 9. 9 x 106 background events Bo r+p 5400 events, S/B = 4. 1 Bo ropo 780 events, S/B = 0. 3 Background po CIPANP 2003 K. Honscheid Ohio State g Bo ropo Signal g m. B (Ge. V)

Our Estimate of Accuracy on a Geant simulation of Bo rp, (for 1. 4 x 107 s) a (gen) Rres Rnon a (recon) Da 77. 3 o 0. 2 77. 2 o 1. 6 o 77. 3 o 0. 4 0 77. 1 o 1. 8 o 93. 0 o 0. 2 93. 3 o 1. 9 o 93. 0 o 0. 4 0 93. 3 o 2. 1 o 111. 0 o 0. 2 111. 7 o 3. 9 o 111. 0 o 0. 4 0. 2 110. 4 o 4. 3 o minimum c 2 Example: 1000 Bo rp signal + backgrounds With input a=77. 3 o CIPANP 2003 K. Honscheid Ohio State non-resonant non-rp bkgrd

Bs Mixing (Vtd/Vts) Dms (~xs) = DG·C where C can be calculated inside the S. M. CDF sensitive to xs ~ 30 DG/G: Bs->yf seen Expect s(DG/G) ~ 2% after Run II 6 5 4 BTe. V reaches sensitivity to xs of 80 in 3. 2 years CIPANP 2003 K. Honscheid Ohio State 3 2 1

One of several ways to determine g: Bs Ds±K • Theoretically clean, BR ~ 10 -4 s ~ 6. 5 Me. V/c 2 s = 168 mm CIPANP 2003 K. Honscheid Ohio State Ds mass (Ge. V) Bs vtx resolution (mm) s = 418 mm Ds vtx resolution (mm)

g from Bs D-s K+ , D+s K- (II) Needed: ü Hadronic trigger ü K/p separation q From the measurement of 4 time-dependent asymmetries one gets g 2 dg ü Good proper time resolution q 2 same order tree level amplitudes ( 3) : large asymmetries, NP contributes unlikely Sensitivity depends upon • relative amplitudes • strong phase difference • values of g, Dms , DGs /Gs For Dms=20 ps– 1: s(g) ~ 10 o For Dms=30 ps– 1: s(g) ~ 12 o CIPANP 2003 K. Honscheid Ohio State In one year: 8 k Bs Ds K reconstructed events From M. Musy

Measuring c In the SM the phases and magnitudes are correlated: Silva & Wolfenstein (hep-ph/9610208) Aleksan, Kayser & London = |Vus| = 0. 2205± 0. 0018 c is the phase of Vts -> Bs Mixing Good: Bs->J/yf plus non-trivial angular analysis Better: Bs -> CP eigenstate such as Bs J/yh( ) , h gg, h rg CIPANP 2003 K. Honscheid Ohio State

Measuring c II BTe. V can reconstruct h and h’ Yield in one year Bs J/y h: 2, 800 events with S/B = 15 Bs J/y h : 9, 800 events with S/B = 30 Error on sin(2 c) = 0. 024 With c ~ 2 o a precision measurement will require a few years. CIPANP 2003 K. Honscheid Ohio State

Physics Reach (CKM) in 107 s Reaction B(B) (x 10 -6) S/B Parameter Error or (Value) B s Ds K - 300 7500 7 g - 2 c 8 o B s Ds p - 3000 59, 000 3 xs (75) 445 168, 000 10 7 250 2. 3 B- Do (K+p-) K- 0. 17 170 1 B- Do (K+K-) K- 1. 1 1, 000 >10 Bo J/y KS J/y l+ l - Bo J/y Ko, Ko p l n Bs J/y h, 330 2, 800 15 Bs J/y h 670 9, 800 30 Bo r+p- 28 5, 400 4. 1 Bo ropo 5 780 0. 3 Reaction B(B) (x 10 -6) CIPANP 2003 K. Honscheid Ohio State # of Events S/B sin(2 b) 0. 017 cos(2 b) ~0. 5 13 o g sin(2 c) 0. 024 a ~4 o Parameter Error B- KS p- 12. 1 4, 600 1 Bo K+p- 18. 8 62, 100 20 Bo p+p- 4. 5 14, 600 3 Asymmetry 0. 030 Bo K+ K- 17 18, 900 6. 6 Asymmetry 0. 020 <4 o + g Theory err.

Bc mesons CDF: m. Bc = 6. 4 +/- 0. 4 Ge. V t. Bc ~ 0. 5 ps BTe. V/LHCb: Precision measurements of mass, lifetime Search for CPV in Bc -> J/y. D+ or Bc -> Ds. D LHCb acceptance ~30% p (Ge. V) LHCb preliminary study s(pp Bc) ~300 nb 109 Bc/ year Bc J/y p (BR ~10 -2) e ~ 2% CIPANP 2003 K. Honscheid Ohio State 12 k events/year Background from B J/y X and prompt J/y reduced cutting on the distance between primary vertex and Bc vertex M( J/y(mm) p) Ge. V/c 2

Part II: Search for New Physics CIPANP 2003 K. Honscheid Ohio State For a nice overview see: S. Stone “BTe. V Physics” at http: //doe-hep. net/P 5 Stone. March 2003. pdf

First Example: Supersymmetry: In general 80 constants & 43 phases MSSM: 2 phases (Nir, hep-ph/9911321) New Physics in Bo mixing: q. D , Bo decay: q. A, Do mixing: f. Kp Process Quantity SM New Physics Bo J/y. Ks CP asym sin(2 b) sin 2(b+q. D) Bo f. Ks CP asym sin(2 b) sin 2(b+q. D+q. A) Do K-p+ CP asym 0 ~sin(f. Kp) New Physics CIPANP 2003 K. Honscheid Ohio State Difference NP

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 g, b sg b dg b sl+l- Exclusive Rare Decays such as B rg, K*g B K*l+l. Dalitz plot & polarization CIPANP 2003 K. Honscheid Ohio State Bo K*g l+l-

Yield, S/B for Rare b Decays Reaction CIPANP 2003 K. Honscheid Ohio State B (10 -6) Signal S/B 11 Bo K*om+m- 1. 5 2530 B- K-m+m- 0. 4 1470 3. 2 b sm+m- 5. 7 4140 0. 13 Physics Polarization; Rate; Wilson coefficents

Polarization in Bo K*om+m. BTe. V data compared to Burdman et al calculation Dilepton invariant mass distributions, forward-backward asymmetry discriminate among the SM and various supersymmetric theories. Ali et. al, hep-ph/9910221 (Ali, Lunghi, Greub & Hiller, hep-ph/0112300) CIPANP 2003 K. Honscheid Ohio State One year for K*l+l-, enough to determine if New Physics is present

Rare Leptonic Decays B s 0 m m Standard Model BR ~ 4 x 10 -9 Here the General Purpose Detectors have an advantage : high p. T di-muon triggering at high (1 x 1034) luminosity. CMS : 100 fb-1 (107 s at 1034 cm-2 s-1) ~26 signal events 6. 4 events background Muon trigger : 2 m’s with p. T > 4 Ge. V | h| < 2. 4 CIPANP 2003 K. Honscheid Ohio State Search also for Bd 0 m m Standard Model BR ~ 1 x 10 -10

Another Example: Extra Dimensions Aranda & Lorenzo Diaz-Cruz, “Flavor Symmetries in Extra Dimensions” (hep-ph/0207059) (Buras et al. hep-ph/0212143) Extra spatial dimension is compactified at scale 1/R = 250 Ge. V on up No effect on |Vub/Vcb|, DMd/DMs , sin(2 b) Bs -> mm – 8% |Vtd| CIPANP 2003 K. Honscheid Ohio State – 100 g +72%

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 BTe. V and LHCb with an efficient, unbiased trigger and a high performance DAQ a superb charged particle tracking system good particle identification excellent photon detection CIPANP 2003 K. Honscheid Ohio State

Additional Transparencies from BTe. V and LHCb Studies CIPANP 2003 K. Honscheid Ohio State

dg (= c) from B s J/y f q In SM f. S = 2 dg = 2 l 2 h ~10 -2 q Sensitive to New Physics effects in the Bs-Bs system In one year: 109 k events Bs J/y (m+m-) f 19 k events Bs J/y (e+e-) f J/y f is not CP eigenstate: needs fit to angular distributions of decay final states as a function of proper time s =36± 1 fs Assuming Dms=20 ps– 1: s (2 dg) ~ 2 o CIPANP 2003 K. Honscheid Ohio State From M. Musy

Current status of LHCb Physics Reach in 1 year (2 fb– 1) Channel Yield Precision* 119 k s(b) 0. 6 o 8 k 27 k, 35 k s(g) 10 o s(g) 3 o b Bd J/y Ks g Bs Ds. K Bd pp, Bs KK a Bd p p 27 k s(a) 5 o- 10 o 2 dg Bs J/y f 128 k s(2 dg) 2 o |Vtd/Vts| Bs Dsp 72 k Dms up to 58 ps 1 rare decays Bd K * g 20 k All numbers will be updated together with more channels in the re-optimization LHCb TDR (September 2003) CIPANP 2003 K. Honscheid Ohio State From M. Musy

A simplified trigger comparison CIPANP 2003 K. Honscheid Ohio State From U. Egede

Unitarity Triangles Bd 0 p p Bd 0 r p B S 0 DS p Bd 0 DK*0 B S 0 DS K Bd 0 D* p, 3 p Bd 0 J/y KS 0 dg = c CIPANP 2003 K. Honscheid Ohio State BS 0 J/y f From N. Harnew