1. LHCb impact on CKM fits Vincenzo Vagnoni (for the LHCb Collaboration) BOLOGNA Nagoya, Thursday 14 th December 2006

2. 2 LHCb startup and baseline luminosity programme  Startup of LHC beam in 2007 Pilot run at 450 GeV per beam with full detector installed Establish running procedures Time and space alignment of the detectors, calibrations  2008: LHC ramps up to 7 TeV per beam Complete commissioning of detector and trigger at 14 TeV Including calibration of momentum, energy and particle ID Start of first physics data taking  Baseline LHCb luminosity programme Integrated luminosity of ~0.5 fb -1 delivered in 2008, ~2 fb -1 in subsequent years physics results with 2 fb -1 available in 2010, 10 fb -1 available in 2014 Ongoing discussion for an upgrade beyond 2014: Super-LHCb  Note: instantaneous luminosity at the LHCb IP of 2·10 32 cm -2 s -1 is almost two orders of magnitude below the LHC challenges* Thus we expect the LHCb luminosity requirements can be fulfilled very early in the LHC operation * the B-physics reach of Atlas and CMS will not be considered in this talk

3. 3 Lattice QCD prospects  To exploit precision measurements where hadronic parameters play a role, a substantial improvement should be achieved during the following decade Now Pre-LHCb 6 TFlop year 2010 40 TFlop year 2014 1 PFlop year 11%5%4%2% 13%5%4%2% 5%3%2.5%1.5% V ub -excl.* 11%6%5%3% V cb -excl.* 4%2%1.5%1% 6 TFlop year and 10 TFlop year predictions from S. Sharpe @ Lattice QCD: Present and Future, Orsay, 2004 and report of the U.S. Lattice QCD Executive Committee Projections to far future from V. Lubicz @ SuperB IV Workshop Uncertainties in LQCD calculation dominated by systematic errors, overall accuracy does not improve according to simple scaling laws Disclaimer: estimates on a 10 years scale very difficult... to be taken cum grano salis * no improvements on Vub- and Vcb-inclusive determinations assumed

4. 4 Where will we be at the end of the B-factories and the Tevatron? (i.e. before LHCb data)  B d /B + sector: B-factories Assume an integrated luminosity of 2 ab -1 at the  (4S) provided by BaBar and Belle together, and...  (  )  6.5° From B  , B   SU(2) analyses, and B  (  ) o time dependent Dalitz  (  )  6.5° From B  DK, GLW, ADS and Dalitz analyses  Assuming significant reduction of the systematics, in particular improvements in the knowledge of the D decay model, e.g. using CLEO-c data and/or model independent fits on the Dalitz plane  (sin2  )  0.017  B s sector: Tevatron Assume (2x) 6 fb -1 collected by CDF and D0, and...  (  s )  0.2  (  s /  s )  0.04  (  m s )  0.5% First direct measurement of  s from D0 available:  s = -0.79 ± 0.56 ± 0.01 (see talk by B. Casey) (I)

5. 5 Summer 2006 Where will we be at the end of the B-factories and the Tevatron? (i.e. before LHCb data) (II) 2008*  Nice improvement in 2008, in particular for  mostly due to better  and LQCD * Every projection to the future shown in this talk has been obtained by fine-tuning the central values of future measurements around Standard Model expectations, i.e. no New Physics assumed !

6. 6 LHCb impact with first year physics data (int. L=0.5fb -1 )  Data taking in 2008 will be crucial to understand detector and trigger performance and assess the LHCb potential  Can use well established measurements from the B-factories and the Tevatron to “calibrate” our CP sensitivity B-factory sin2  (final sensitivity ~0.017) vs LHCb-2008 J/  K S sin2  (~0.04) Will demonstrate with already considerable precision that we can keep under control the main ingredients of CP-analyses, e.g. opposite side tagging Tevatron  m s (final sensitivity ~0.09 ps -1 ) vs LHCb-2008 (~0.014 ps -1, stat. only) Hadronic trigger, control of proper time resolution, same side K tagging, etc. (I)

7. 7 LHCb impact with first year physics data (int. L=0.5fb -1 )  Perform the first high precision measurement of  s Tevatron  s (final sensitivity ~0.2) vs LHCb-2008 (~0.04) Could make a 5  discovery of New Physics effects in the B s mixing phase with the first year of data if NP  s is O(10°)  Bring down the limit of BR(B s   ) Other big milestone in the search for New Physics (see talk by J. Dickens) Potential to exclude BR between 10 -8 and SM value with the first year only !  Other relevant measurements e.g. b-hadron lifetimes, B  h + h - ’ (see J. Nardulli),...  First results with “more difficult” measurements... get a taste of! e.g. Dalitz analyses of B  DK and B  (   (II)

8. 8  (sin2  ) now pre-LHCb with LHCb at L=2fb -1 with LHCb at L=10fb -1 year sin2  from B d  J/  K S   The golden mode at B-factories, already well known, but still relevant to improve the measurement background subtracted CP asymmetry with L=2fb -1 In one LHCb year (L=2fb -1 ) B d  J/  (  )K S Yield: ~216k B d  J/  (  )K S events with B/S  0.8 Sensitivity:  (sin2  ) = 0.02 Overall improvement by roughly a factor 2 with LHCb at L=10 fb -1

9. 9  s and  s at LHCb  B s  J/  is the el-dorado mode at LHCb counterpart of B d  J/  K S for measuring the B s mixing phase, but also other modes contribute Signal yield: 130k events per L=2fb -1 with a B/S  0.1 very sensitive probe of New Physics effects in the B s mixing  s =  s (SM) +  s (NP)  s (SM)=-2 2 , small and very well known from indirect UT fits: -0.037±0.002 Sensitivity with L=2 fb -1 Channels under study ss0.021 B s  J/ , B s  c , B s  J/ , B s  D s D s Γs/ΓsΓs/Γs0.0092 B s  J/  slight complication: 2 CP-even and 1 CP- odd amplitudes, angular analysis is needed to separate the states  s poorly known now, but will be known as well as sin2  thanks to LHCb See J. van Hunen’s talk now pre-LHCb LHCb at L=2fb -1 LHCb at L=10fb -1 year (s)(s) now pre-LHCb LHCb at L=2fb -1 LHCb at L=10fb -1 (s)(s)

10. 10 Sensitivity to      more challenging for LHCb, due to the need of reconstructing  o ’s in hadronic environment  2 analyses under study  Time-dependent B d  (  ) o Dalitz plot   with L=2 fb -1 LHCb estimates a sensitivity σ  10°  B  SU(2) analysis Very preliminary studies indicate the need of a few years of LHCb running to improve the current B d  +  - measurement. With 2 fb -1 the main LHCb contribution will be most likely the improved measurement of B d   o  o (fully charged final state)  Need more time and refined studies to give firm results for  In the following we will conservatively assume to measure alpha with the B d  (  ) o mode only  (  ) [ o ] now pre-LHCb with LHCb at L=2fb -1 with LHCb at L=10fb -1 d o only LHCb B d  (  ) o only year N 3π = 14k events / 2 fb -1, B/S~1 0000 -+-+ +-+-

11. 11  Several modes to measure  at LHCb ADS+GLW Dalitz analysis with D  3-body “Dalitz” analysis with D  4-body Golden B s  D s K mode  Sensitivity estimated at ~4.2° with L=2fb -1 Assuming the same improvements of the Dalitz syst. error as for the projections of the B-factories to 2008 B mode D mode B + →DK + K  + KK/  + K3  B + →D*K + KKKK B + →DK + K s  B + →DK + KK  B + →DK + K  B 0 →DK *0 K  + KK +  B 0 →DK *0 K s  Bs→DsKBs→DsKBs→DsKBs→DsK KK  m+m+ m-m- LHCb simulation  (770) K * and DCS K *  (  ) [ o ] now pre-LHCb with LHCb at L=2fb -1 with LHCb at L=10fb -1 year Sensitivity to  By 2014 sensitivity at about 2 degrees See M. Patel’s talk

12. 12 Unitarity Triangle prospects from LHCb only LHCb L=2 fb -1 LHCb L=10 fb -1 Using , ,  and  m s from LHCb only + theory for  m d /  m s Not employing the full LHCb potential for  in this study Somewhat conservative: just  from (  ) o 2010 2014

13. 13 Unitarity Triangle in 2014 With LHCb at L=10fb -1 Without LHCb

14. 14 Allowing for New Physics in the mixing The mixing processes being characterized by a single amplitude, they can be parametrized in a general way by means of two parameters H SM eff includes only SM box diagrams while H full eff includes New Physics contributions as well For the neutral kaon mixing case, it is convenient to introduce only one parameter Four “independent” observables C Bd,  Bd, C Bs,  Bs C Bq =1,  Bq =0 in SM 5 additional parameters (  ) with NP allowed Summer 2006 Using Tree-level processes assumed to be NP-free * the effect in the D 0 -D 0 mixing is neglected

15. 15 The  -  plane in 2014 allowing for NP in the mixing  By allowing for arbitrary NP contributions in the mixing, the UT apex will be basically determined by the Tree-level constraints, and it will be the reference for any NP model building caveat: neglecting here NP effects in neutral D-meson mixing  LHCb will further constrain the apex, due to substantial improvement in the  measurement Without LHCb With LHCb at L=10 fb -1

16. 16  Dramatic impact of LHCb on the B s mixing phase can bring down the sensitivity to the NP contribution  Bs from 5.6° at the end of the Tevatron to 0.3° NP in the B s mixing will be known three times better than in the B d by 2014 without the need of improvements from theory Measuring New Physics in the B s mixing End of Tevatron With LHCb at L=10 fb -1 in 2014 As far as C Bd and C Bs are concerned, they are dominated by theory  no great impact from LHCb measurements  (C Bs )~0.06  (C Bd )~0.09

17. 17 Interpretation of  s vs sin2   Most precise measurements today available are  m d /  m s, sin2  and |V ub /V cb |  A disagreement between  m d /  m s and  would spot out NP in the magnitude of the mixing amplitudes But uncertainty on  still too large  To find evidence of NP effects in the B d mixing phase, it is instead important to compare sin2  with |V ub /V cb | but need to heavily rely on Lattice QCD, interpretation in case of slight disagreement not trivial Example: current UT fits show slight disagreement between sin2  and |V ub /V cb |, due to excess of V ub -inclusive / defect of sin2  (JHEP 0610 (2006) 081) First NP hint or theory problem in V ub ?  s, just go and measure it ! If different from -0.037±0.002, NP is there No such interpretation problems for  s, just go and measure it ! If different from -0.037±0.002, NP is there

18. 18 Conclusions  LHCb will improve the knowledge of the Unitarity Triangle in particular due to increased precision on the measurement of  and , and maybe to a lesser extent of  both in Standard Model and (even more) in NP allowed scenarios  LHCb will measure the B s mixing phase with ultimate precision Impressive improvement of a factor 20 since the end of Tevatron data taking NP angle  Bs will be known at 5.6° from the Tevatron, and 0.3° at LHCb (with int. L=10fb -1 ) ! Much easier intepretation than sin2 , NP might show up very early just with the first year of data in 2008 After “LHCb phase I”, in 2014, NP in the B s mixing will be more constrained than in the B d  Other big milestones from LHCb, not impacting on CKM fits or not considered in this talk Radiative and rare decays B d  K* , B s  , B d  K* , B s   b  sss penguins e.g. B s   B  hh’ Charm physics,...

19. 19 Backup

20. 20 ~1 cm B Tracking: Vertex Locator, TT, T1, T2, T3 PID: 2 RICH detectors, SPD/PS, ECAL, HCAL, Muon stations Interaction point The LHC beauty experiment Forward-backward correlation of bb angular distribution - b b b b Pythia 100μb 230μb η of B-hadron P T of B-hadron Single-arm forward spectrometer, acceptance: 15-300 mrad pp at 14 TeV “b-factory” Luminosity at IP8 = 2·10 32 cm -2 s -1 10 12 bb produced per year including all b-hadrons species

21. 21 4 devices: Scintillator Pad Detector (SPD), Preshower (PRS), Electromagnetic Calorimeter (ECAL) and Hadronic Calorimeter (HCAL). Provides with acceptance 30 mrad to 300 (250) mrad: Level-0 trigger information (high transverse momentum hadrons, electrons, photons and p 0, and multiplicity) Kinematic measurements for  and  0 with  E /E = Particle ID information for e, , and  0. LHCb Calorimeter EE  1% 10%

22. 22  0 reconstruction at LHCb Resolved  0 : reconstructed from 2 isolated photons  m = 10 MeV/c 2 Merged  0 : pair of photons from high energy pion which forms a single ECAL cluster, where the 2 showers are merged. The pair is reconstructed with a specific algorithm based on the expected shower shape.  m = 15 MeV/c 2 Reconstruction efficiency:   0 = 53 % for B 0  +  -  0 Resolved π 0 Merged π 0 π 0 mass (Mev/c²) Merged Resolved Transverse energy (GeV) 

23. 23 Tree level determination of  from B ±  D (*)0 K (*)± b u BB u u KK c s W D  V ub = |V ub | e -i  DD b u BB c u u s KK V cb W strong phase difference between V ub and V cb mediated transitions strong amplitude (the same for V ub and V cb mediated transitions r B is a crucial parameter - the sensitivity on  depends on it GLW (Gronau,London,Wyler) Uses CP eigenstates of D 0 decays ADS (Atwood, Dunietz, Soni) Dalitz Method – GGSZ analyze D 0 three-body decays on the Dalitz plane Favoured Colour suppressed Interference if same D 0 and D 0 final states Break-through of B-factories, but statistically limited and extremely challenging!

24. 24 Bounds on NP size and phase BdBd BsBs dark: 68% light: 95% dark: 68% light: 95% The allowed NP amplitude is still large for small phase shift MFV scenarios are strongly favored at this point, but we still might see a large NP phase in B s mixing

25. 25 New Physics in the b  d and recently in b  s sector starts to be quite constrained and most probably will not come as an alternative to the CKM picture, but rather as a «correction» MFV or not MFV? Minimal Flavour Violation: the only source of flavour violation is in the SM Yukawa couplings (implies  =0) New Physics couplings between third and second families (b  s sector) stronger with respect to the b  d ones Flavour physics needs to improve existing measurements in the B d sector and perform precise measurement in the B s sector (mixing phase still largely unknown)

26. 26 LHCb sensitivity: summary 2010 L=2 fb -1 2014 L=10 fb -1 4.2°2.4° sin2  0.020.009  from (  )° only 10°7° ssss0.0210.009  s /  s 0.0090.004

27. 27 Pre-LHCb20102014 6.5°3.5°2.3° sin2  0.0170.0130.008 6.5°5.4°4.8° ssss0.20.0210.009  s /  s 0.040.0090.004 Pre-LHCb: B-factories and Tevatron at end of their life, 2008-2009 Perspectives up to 2014