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B physics in the LHC program Does flavor physics in the LHC era increase our understanding?

QCDWorkshop Martina Franca, June 16–19, 2007. B physics in the LHC program Does flavor physics in the LHC era increase our understanding?. Clara Matteuzzi. INFN and Universita Milano-Bicocca. Contents. Present status of the CKM 2. The start up of LHC

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B physics in the LHC program Does flavor physics in the LHC era increase our understanding?

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  1. QCDWorkshop Martina Franca, June 16–19, 2007 B physics in the LHC programDoes flavor physics in the LHC era increase our understanding? Clara Matteuzzi INFN and Universita Milano-Bicocca Clara Matteuzzi

  2. Contents • Present status of the CKM • 2. The start up of LHC • 3. Experiments at LHC: potential • (some examples) • 4. B physics beyond 2009 Clara Matteuzzi

  3. Where is Flavour Physics now ?? • The PEP-II/BABAR and KEKB/BelleB Factories, together with CLEO-c and recent K decay experiments, have reached the precision measurement regime for many parameters • CDF and DØ at Tevatron Run II are now producing beautiful results on Bs mixing, rare decays and b baryon studies Clara Matteuzzi

  4. Current status of CKM parameters = 0.2258±0.0011 A = 0.83±0.02  = 0.168±0.029  = 0.340±0.017 With 2 ab-1 δ(ρ,η) = (10%,4.4%) Accuracy of angles is limited by experiment: α ~ ±12° β ~ ± 1° γ ~ ± (20°-30°)χ not yet measured Accuracy of sides is limited by theoretical uncertainty Clara Matteuzzi

  5. Current status of CKM parameters Goal of heavy flavour physics is now shifting from understanding of CKM in the Standard Model (SM)to search for physics Beyond the Standard Model (BSM) appearing in loops. Clara Matteuzzi All measurementsrelated with electroweak quark transitions are coherent with the CKM picture of the Standard Model Overconstrained tests of the CKM matrix to the level of precision warrented by theoretical uncertainties (will theory be able to calculate hadronic parameters with 1% precision in 10 years?) The CKM phase is consistent with being the source for all observed CP-violating phenomena There must, however, be additional sources of CP violation

  6. LHCb ATLAS/LHCf CMS/TOTEM ALICE The LHC era begins …….. Clara Matteuzzi

  7. The LHC experiments LHC starts at √s = 14 TeV middle of 2008 ALICE heavy ion and pp experiment ATLAS general purpose pp experimentCMS general purpose pp experiment LHCb dedicated Heavy Flavour experiment Middle of 2008: Start of run @ s = 14 TeV calibration and trigger commissioning, increasing luminosity toward 1033 for ATLAS/CMS and ~21032 for LHCb for physics From 2009: Stable physics run @ s = 14 TeV ATLAS and CMS: clear interest to increase luminosities towards 1034 as quick as possible. B physics will become increasingly difficult. LHCb: collecting data with <1033 for some years Clara Matteuzzi

  8. The flavour stage The stage ……….. 2008 physics run for a period of 1/4 of the nominal year (107 sec) <L>=1033 for ATLAS and CMS (optimistic?) <L>=21032 for LHCb (should be possible…)Ldt = 2.5 fb each for ATLAS and CMS (if <L> is lower, trigger could be adjusted to have a similar number of b’s) Ldt = 0.5 fb for LHCb 2009-2011 ATLAS and CMS accumulate Ldt = 30 fb each end of B physics era and move to 1034 regime (except Bs)2009-2013 LHCb collect Ldt≥10 fb data by the end of 2013±1 Clara Matteuzzi

  9. The flavour stage Data samples at the start of the LHC era • BABAR and Belle will each have collected a total data sample of approximately 1 ab-1 by ~2008 • 2 ab-1 = 2 x 109 produced B0B0, B+B- pairs • The Tevatron Run II experiments CDF and DØ will each have collected ≤ 8 fb-1 by ~2009 CDF and D0, well understood detectors Clara Matteuzzi

  10. b - physics atthe LHC Given the fact that • LHC will be the facility producing the largest number of b hadrons (of all types), by far, and for a long time • the Tevatron experiments have demonstrated the feasibility of B physics at hadron machines Perform a dedicated b-physics experiment at the LHC • to exploit the huge bb production in the not-well-known forward region, despite the unfriendly hadronic environment (multiplicity, …) for b-physics • ~ 230 b of bb production in one of the forward peaks (400 mrad),corresponding to nearly 105 b hadrons per secondat a low luminosity of 21032 cm–2s–1 Clara Matteuzzi

  11. Dedicated to b physics Works at L=2x1032 cm-2 sec-1 1.9 <  < 4.9 or 15 <  < 300 mrad Special features: a dedicated trigger and Particle Identification The LHCb spectrometer Vertex Locator (Silicon) Muon System RICH counters p/K/p Identification Tracking Calorimeters Clara Matteuzzi

  12. Central detectors | η | < 2.5 The LHC experiments CMS ATLAS b physics trigger: high pt leptons (6-7 GeV/c m , 12 GeV e) no hadronic trigger Mostly b physics with J/Y and rare decays with leptons (and at low luminosity) Clara Matteuzzi

  13. Particles Identification in LHCb • Efficient hadron PID crucial for many channels. • Calibration of K/ PID on data will be performed using the D*+D0+, D0 K+- decay chain Ex. The Bh+h- channels ππ hypothesis πK hypothesis No PID With PID KKhypothesis πK hypothesis Clara Matteuzzi

  14. Is there New Physics in B decays ?? (after all, the CKM picture of CPV does not account for the presence of matter in the Universe…) • Some quantities very sensitive to NP are yet to be measured or lacking precise measurement • Four examples • c arg(Vts)-pvia phase of Bs mixing • CKM fit prediction is very precise • Branching ratiosof rare decays • Expect large contributions from NP models • Angular distributions • Sensitive to non-SM operators in interactions • g -arg(Vub) • Tree processes assumed free of NP • Comparison with measurements from loop processes can reveal NP Clara Matteuzzi

  15. s from Bs J/ decays Clara Matteuzzi

  16. s from Bs J/ decays SU(3) counterpart of Bd→J/Ks and measures the Bs- Bs mixing phase The phaseof the oscillation in the SM is given by: fsSM  -2  arg (Vts) -2c = -2l2h ~ -0.04 very small , so very sensitive to NP Prediction from a global fit to CKM measurements(UT fit): fs= -0.037± 0.002 Recent D0 measurement: fs= -0.79±0.56(stat)(syst) • Note:no Bs produced in B factories +0.14 - 0.01 Clara Matteuzzi

  17. s from Bs J/  decays Bs(Bs)→J/ψ(μ+μ-)φ(K+K-) can proceed directly or through mixing Bs0 Bs0 Bs0 Measure time dependent CP asymmetries Need flavour tagging Proper time resolution Clara Matteuzzi

  18. Total CP-even CP-odd Bs→J/ψ(µ+µ-) Φ(K+K-) golden channel High branching ratio (3x10-5), good experimental signature Final states with leptons: lepton trigger very effectivefor ATLAS, CMS and LHCb However J/ is not a pure CP eigenstate Full decay topology analysis is needed to determineCP even and CP odd statesJ/(CP = +1) / J/ (CP = ) (LJ/-= 0, 2 vs LJ/- = 1) LHCb Clara Matteuzzi

  19. eff = tag(1  2wwrong)2 [10] O.S. S.S. “combined” e  K Jet K ATLAS 0.25 0.68  3.63  =4.56 CMS under investigation  LHCb 0.46 0.70 1.64 1.04 2.71 N.N. = 7.08 Bs→J/ψ(µ+µ-) Φ(K+K-) golden channel Time dependent CP asymmetries in Bs, Bs J/ decays need : 1. Flavour tagging: opposite side (O.S.) : lepton, jet-charge and kaon same side (S.S.) : “slow” kaon from the fragmentation Clara Matteuzzi

  20. ATLAS CMS LHCb[fs] 83 77 36 2.Good proper time resolution: NB:worse resolution =more dilution in the CPasymmetries Bs-Bs oscillation has to be well resolved -good that ms is not too big -resolution function must be well understood measuring lifetimes, oscillation plot with Ds etc. Proper time resolutions Clara Matteuzzi

  21. ATLAS CMS LHCbm[MeV/c2] 16.5 14 14B/S 0.25 0.33 0.12 ATLAS CMS LHCbm[MeV/c2] 16.5 14 14B/S 0.25 0.33 0.12 3.Good mass and vertex resolutions Bs mass resolutions and Background/Signal ratios with J/ mass constraintwithout mass constraint Clara Matteuzzi

  22. ATLAS CMS LHCbNrec 23 k 27k 33 kNreceff-tag 1.0 k ? 2.3 k Event yields from the “2008” run Numbers of reconstructed J/ and those effectively flavour tagged Clara Matteuzzi

  23. Sensitivity to Φs andΔГs ATLAS CMS LHCb(s) 0.158 ? 0.042(s)/s 0.41 0.13 0.12 With 2008 data LHCb: BSM effect down to the level of SM can be excluded/discovered with the 2008 data (J/, c, DsDscan be added. No angular analysis needed, but smaller statistics) With > 2009 data ATLAS and CMS:(s) ≈ 0.04 with L dt = 30 fb data By ~2013, SM prediction of s tested to a level of ~5 LHCb:stat(s) ~ 0.01 with  L dt = 10 fb Clara Matteuzzi

  24. Φs : sensitivity to New Physics From Z. Ligeti et al hep-ph/0604112 Allowed regions CL > 0.90, 0.32, 0.05 • One nominal LHCb year (2 fb-1): s(fs)= 0.023 ( UT fit value: -0.037) • The measurement can be interpreted via a parametrization of NP effects Then Dms and fs can be written: 180o 2006with first Dms measurement 90o ss Allowed region 0o 0.5 1.5 2.5 hs 180o fs= 0.04±0.03 90o ss LHCb, L=2fb-1 0o 0.1 0.3 0.5 hs 24 Clara Matteuzzi

  25. Search for rare B decays Clara Matteuzzi

  26. Search for Bs +– SM expectation: BR(Bs→µ+µ-)= (3.4±0.4) x 10-9 BR(Bd→µ+µ-) = (1.0±0.5) x 10-10 World best limit by Dø: BR(Bs→µ+µ-) < 7.5 x 10-8@90%CL SM In Supersymmetry: Large contributions in some SUSY models BR(Bd,s→µ+µ-) could be very sensitive to high values of tan β. Clara Matteuzzi

  27. ATLAS CMS LHCbm[MeV/c2] 77 36 18 Search for Bs +– • Final states with leptons: lepton trigger very effectivefor ATLAS, CMS and LHCb • Main issue is background rejection: bX + bX • Bc±→ J/ψ(µ+µ-)µ±ν • B, K, etc. • BX, etc. + isolation in pT, etc. Adressed by excellent mass resolution vertex resolution and particle ID Bs mass resolutions Bs Clara Matteuzzi

  28. Search for Bs +– assuming the SM Br = ~3.510 With 2008 data ATLAS , CMS Br (B μμ) <~510 (90%CL) LHCb limit on BR at 90% CL (only bkg is observed) LHCb: BSM contribution down to the level of SM can be excluded/discovered.  Expected CDF+D0 Limit2x10-8  Uncertainty in bkg prediction SM prediction  Integrated Luminosity (fb) LHCb uses “distributions” for signal and background… Clara Matteuzzi

  29. Search for Bs +– With > 2009 data ATLAS and CMS:  L dt = 30 fb, <~610 (90%CL) (They plan to continue this programme at L=1034, 4 in one year) LHCb:  L dt = 10 fb, >5 observation for SM Br Expected final (8 fb-1) from Tevatron at 90% CL: < 2·10-8 LHCb uses “distributions” for signal and background… Clara Matteuzzi

  30. BR (x10–9) 5 observation SM prediction 3 evidence Integrated luminosity (fb–1) Sensitivity to Bs +– ATLAS performance summary for B mm LHCb sensitivity (signal+bkg is observed) ATLAS sensitivity as a function of integrated luminosity expected to be delivered in three years after LHC start. 1 year @ LHCb Clara Matteuzzi

  31. BR(Bs→µ+µ-) in CMSSM as a Function of gaugino mass 10-6 10-7 D0 limit 10-8 SM 10-9 Sensitivity by LHCb Clara Matteuzzi

  32. Search for rare B0 K*0m+m- decays Clara Matteuzzi

  33. Search for B0 K*0m+m- decay SM processes contributing to decay: BR(B0→lls) = 4.5x10-6 BR(B0→llK) = 0.5x10-6 • BR(B0→K*μ+μ-) = ~1.2 x 10-6 • Decay seen in B factories, ~ no NP in BR Decay is very sensitive to extensions of SM : Analysis of angular distributions allow to extract information about new Physics. Clara Matteuzzi

  34. Observables in B0 K*0μ+μ- decay Forward-backward asymmetry AFB(s) in the  rest-frame is sensitive probe of New Physics: • Predicted zero of AFB(s) depends on Wilson coefficients C7eff/C9eff s = μμ mass squared (= q2) θl = angle between μ and B in μμ rest frame (AFB angle) Transverse Asymmetry: (asymmetry in the spin amplitude of the K*) K*0 polarisation can be measured Clara Matteuzzi

  35. AFB, theory s = (m)2 [GeV2] New Physics in Bd→ K0*mm AFB(s) in SM and different SUSY models: SUSY I = SUGRA SUSY II = MIA MSSM (from Phys.Rev.D61 (2000) 074024) Non-MFV MSSM with tan(β) = 5 from HEP-ph/0612166 AT(2) Clara Matteuzzi

  36. The B0 K*0m+m- decays for one canonical year10 fb (ATLAS) and 2fb (LHCb) ATLASLHCb (m) [MeV/c2] 51 14 Nsignal 800 7200 B/S <4.8 ~0.5 m 00MeV/c Flavour tag not necessary in ATLAS and LHCb (CMS study not yet available) ATLAS LHCb 4500MeV/c m Clara Matteuzzi

  37. + ATLAS precision @ 30 fb-1 + Belle 2006 SM model SM extensions Forward-backward asymmetry in Bd→ K0*mm LHCb 2 fb-1(one canonical year) ATLAS 30 fb-1 AFB LHCb 2 fb-1: ~7k evts B/S<0.5 Zero crossing point σAFB (2fb-1)=1.2 GeV 2 By ~2013, LHCb zero crossing point with 10 fb(s0) = 0.28 (GeV/c2)2 s = (m)2 [GeV2]  determine C7eff/C9eff with 7% stat error (SM) Clara Matteuzzi

  38. The rare decays B±→ K±mm

  39. The rare decaysBu+→K+ll H0/A0? Corrections to unity can be Large ~10% in models that Distinguish between lepton flavors,like interactions involving neutral Higgs boson An interesting ratio Hiller & Krüger, PRD69 (2004) 074020 Clara Matteuzzi

  40. The ratio RK in LHCb With 10 fb data Kee 10 k K 19 k By ~2013 LHCb (RK) = 0.043 Clara Matteuzzi

  41. Tree-level processes allow clean extraction of γ Access interference effects involving the phase between Vub and Vcb Bs DsK B, Bd D(*)K(*), with D0 decaying to: 2 bodies: πK, KK, ππ 3 bodies: KS ππ, KS KK, KS Kπ 4 bodies: K πππ, KK ππ Processes involving large Penguin contributions are sensitive to New Physics Bd+– & Bs  K+K– U-spin approach The CKM angle γin LHCb • From direct measurements withB→DK decays:γ=(83±19)°(BaBar and Belle) • Experimental status: • From the SM fit using only indirect measurements: γ=(63.1±4.6)° (UTFit) LHCb can measure angle γ using various methods L0 hadron pT trigger, K/ identification: essential Clara Matteuzzi

  42. g from Bs DsK DsK asymmetries (5 years, ms=20 ps–1) Ds–K+ Ds+K– • 2 time dependent asymmetries from 4 decay rates: Bs (Bs)  D-sK+, D+sK- • 2 tree decays (b→c)and(b→u)of same magnitudeinterfere via Bs mixing:  large interference effects expected  insensitive to new physics • CP asymmetry measures (g+ fs), withfsbeing determined using Bs → J/y f • needs suppression of Bs Dsπ background (BR~15 higher) Fit the 4 tagged, time-dependent rates: • phase of D-sK+= D + (g + fs) • phase of D+sK-= D - (g + fs)  extract both D and(g + fs) (Bs Dsπ also used in fit to constrain other parameters like mistag rate, Δms, ΔГs) Expect 5400 signal events with B/S<1 at 90% CL  s(g) ~ 10° in 1year/2fb-1 Clara Matteuzzi 42

  43. Weak phase difference =  Magnitude ratio = rB ~ 0.08 colour-allowed colour-suppressed  from B±  DK± • “ADS+GLW” strategy: • Measure the relative rates of B–  DK–andB+  DK+ decays with neutral D’s observed in final states such as: K–+and K+–, K–+–+and K+–+–, K+K– • These depend on: • Relative magnitude, weak phase and strong phase between B–  D0K– and B–  D0K– • Relative magnitudes (known) and strong phases between D0  K–+ and D0  K–+,and between D0  K–+–+ and D0  K–+–+ () = 5–15 with 2 fb–1 Clara Matteuzzi

  44. Weak phase difference =  Magnitude ratio = rB ~ 0.4 colour-suppressed colour-suppressed g from B0 D0K*0 • Treat with same ADS+GLW method • So far used only D decays to K–+, K+–, K+K–and +– final states () = 7–10 with 2 fb–1 Clara Matteuzzi

  45. g from BDK Dalitz analyses • B±  D(KS+–)K±: • D0 and anti-D0 contributions interfere in Dalitz plot • If good online KS reconstruction: 5k signal events in 2 fb–1, B/S < 1 • Assuming signal only and flat acceptance across Dalitz plot: () = 8 with 2 fb–1 • B±  D(KK)K±: • Four-body “Dalitz” analysis • 1.7 k signal events in 2 fb–1 • Assuming signal only and flat acceptance across Dalitz plot: () = 15 with 2 fb–1 Clara Matteuzzi

  46.  from B and BsKK p/K p/K Bd/s Bd/s p/K p/K • large penguin contributions in both decays  sensitive to New Physics • measure time-dependent CP asymmetry for B and BsKK • ACP(t) = Adir cos(Δmt) + Amix sin(Δmt) • Adir andAmix depend on γ, mixing phases, and ratio of penguin to tree = d eiθ • exploit “U-spin” symmetry (ds) [R.Fleischer, Phys.Lett. B459, 306 (1999)] • dππ= dKK and θππ= θKK • 4measurements and 3 unknowns, if mixing phases taken from B0J/KS and BsJ/ Expected sensitivity: • 26k B , 37k BsKK, 135kBK •  σ(γ) ~ 4° in 2fb-1 Clara Matteuzzi

  47. LHCb performance in  determination with 10 fb DsK DK /KK ADS GLW+D Dalitz( 4.5 3.6 3.6 6.7 4 With a weak assumption on U-spin symmetryCould be affected by BSM The CKM angle γin LHCb ADS=Atwood,Dunietz,Sony GLW=Gronau,London,Wyler ~ 2013 LHCb tree determination of  2.4 unaffected by BSM Clara Matteuzzi

  48. ALICE heavy-flavour potential HERA-LHC Workshop CERN/LHCC 2005-014 hep-ph/0601164 • ALICE combines electronic (|h|<0.9), muonic (4<h<2.5), hadronic (|h|<0.9) channels • ALICE is well-equiped for • heavy-flavour studies • using several different channels / strategies • acceptance down low pt at central and forward rapidity • With 109 events (nominal year): • ~5% statistical error on total cross sections (c and b) From A.Dainese (ALICE) Clara Matteuzzi

  49. Heavy flavour physics will play a significant role in deepening our understanding of the Standard Model, and, should New Physics be found at LHC, it provides unique tools for probing the flavour structure of the new particles The effects of new physics loops can be seen in rare decay branching fractions and kinematic distributions and in CP-violating asymmetries in channels with very small branching fractions Conclusions To this improvements will be fundamental better theoretical understanding and predictions Clara Matteuzzi

  50. Conclusions • It is important that other approaches be followed as well: • A Super B-Factory can, in the next decade, provide • high precision measurementsas well as results • complementary to those of hadronic experiments • 2. Rare K decay experiments • 3. Searches for lepton flavor violation The new generation of experiments at LHC , and especially LHCb, will extend the fruitful programs of the current B Factories and Tevatron Clara Matteuzzi

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