LHCb impact on CKM fits Vincenzo Vagnoni (for the LHCb Collaboration) BOLOGNA Nagoya, Thursday 14 th December 2006 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 210 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 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 TFlop year 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. Lattice QCD: Present and Future, Orsay, 2004 and report of the U.S. Lattice QCD Executive Committee Projections to far future from V. 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 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 ) 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 = 0.56 0.01 (see talk by B. Casey) (I) 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 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 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 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 (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 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: 0.002 Sensitivity with L=2 fb -1 Channels under study ss0.021 B s J/ , B s c , B s J/ , B s D s D s s/ss/s 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 Hunens 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 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 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 3 = 14k events / 2 fb -1, B/S~1 0000 -+-+ +-+- 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 + KKKK B + DK + K s B + DK + KK B + DK + K B 0 DK *0 K + KK + B 0 DK *0 K s BsDsKBsDsKBsDsKBsDsK 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. Patels talk 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 13 Unitarity Triangle in 2014 With LHCb at L=10fb -1 Without LHCb 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 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 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 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 0.002, NP is there No such interpretation problems for s, just go and measure it ! If different from 0.002, NP is there 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 Backup 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 100b 230b of B-hadron P T of B-hadron Single-arm forward spectrometer, acceptance: mrad pp at 14 TeV b-factory Luminosity at IP8 = 210 32 cm -2 s bb produced per year including all b-hadrons species 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 EE 1% 10% 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 0 Merged 0 0 mass (Mev/c) Merged Resolved Transverse energy (GeV) 23 Tree level determination of from B D (*)0 K (*) b u BB u u KK c s W D V ub = |V ub | e -i DD b u BB c u u s KK 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 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 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 LHCb sensitivity: summary 2010 L=2 fb L=10 fb -1 4.22.4 sin2 from ( ) only 107 ssss s / s 27 Pre-LHCb 6.53.52.3 sin2 6.55.44.8 ssss s / s Pre-LHCb: B-factories and Tevatron at end of their life, Perspectives up to 2014