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

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 2·1032 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

* no improvements on Vub- and Vcb-inclusive determinations assumed 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% 3% 2.5% 1.5% Vub-excl.* 6% Vcb-excl.* 1% 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 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 * no improvements on Vub- and Vcb-inclusive determinations assumed

Where will we be at the end of the B-factories and the Tevatron. (i. e Where will we be at the end of the B-factories and the Tevatron? (i.e. before LHCb data) (I) Bd/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pp, Brr SU(2) analyses, and B(rp)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 Bs sector: Tevatron Assume (2x) 6 fb-1 collected by CDF and D0, and... (s)  0.2 (s/s)  0.04 (ms)  0.5% First direct measurement of s from D0 available: s= -0.79 ± 0.56 ± 0.01 (see talk by B. Casey)

Where will we be at the end of the B-factories and the Tevatron. (i. e Where will we be at the end of the B-factories and the Tevatron? (i.e. before LHCb data) (II) Summer 2006 2008* Nice improvement in 2008, in particular for r 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 !

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/KS 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 ms (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.

LHCb impact with first year physics data (int. L=0.5fb-1) (II) 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 Bs mixing phase with the first year of data if NP s is O(10°) Bring down the limit of BR(Bsmm) 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(rp)o

sin2 from BdJ/KS The golden mode at B-factories, already well known, but still relevant to improve the measurement In one LHCb year (L=2fb-1) Yield: ~216k BdJ/(mm)KS events with B/S0.8 Sensitivity: s(sin2b) = 0.02 s(sin2b) now pre-LHCb with LHCb at L=2fb-1 with LHCb at L=10fb-1 year background subtracted CP asymmetry with L=2fb-1 Overall improvement by roughly a factor 2 with LHCb at L=10 fb-1

s and s at LHCb Bs J/ is the el-dorado mode at LHCb counterpart of BdJ/KS for measuring the Bs 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 Bs mixing s = s(SM) + s(NP) s(SM)=-2l2h, small and very well known from indirect UT fits: -0.037±0.002 slight complication: 2 CP-even and 1 CP-odd amplitudes, angular analysis is needed to separate the states Sensitivity with L=2 fb-1 Channels under study s 0.021 BsJ/, Bsc, BsJ/, BsDsDs Γs/Γs 0.0092 BsJ/ now pre-LHCb LHCb at L=2fb-1 LHCb at L=10fb-1 year s(s) s poorly known now, but will be known as well as sin2b thanks to LHCb See J. van Hunen’s talk

Sensitivity to   more challenging for LHCb, due to the need of reconstructing o’s in hadronic environment 2 analyses under study Time-dependent Bd(rp)o Dalitz plot  with L=2 fb-1 LHCb estimates a sensitivity σ10° Brr SU(2) analysis Very preliminary studies indicate the need of a few years of LHCb running to improve the current Bdr+r- measurement. With 2 fb-1 the main LHCb contribution will be most likely the improved measurement of Bd roro (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 Bd(rp)o mode only r+p- r0p0 N3π = 14k events / 2 fb-1, B/S~1 r-p+ s() [o] now pre-LHCb with LHCb at L=2fb-1 with LHCb at L=10fb-1 LHCb Bd(rp)o only year

By 2014 sensitivity at about 2 degrees Sensitivity to  m+ m- LHCb simulation r(770) K* and DCS K* Several modes to measure  at LHCb ADS+GLW Dalitz analysis with D3-body “Dalitz” analysis with D4-body Golden BsDsK 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 s(g) [o] now pre-LHCb with LHCb at L=2fb-1 with LHCb at L=10fb-1 year B mode D mode B+→DK+ Kp + KK/pp + K3p B+→D*K+ Kp Kspp KKpp Kppp B0→DK*0 Kp + KK + pp Bs→DsK KKp By 2014 sensitivity at about 2 degrees See M. Patel’s talk

Unitarity Triangle prospects from LHCb only 2010 2014 LHCb L=2 fb-1 LHCb L=10 fb-1 Using , ,  and Dms from LHCb only + theory for Dmd/Dms Not employing the full LHCb potential for  in this study Somewhat conservative: just  from (rp)o

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

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 HSMeff includes only SM box diagrams while Hfulleff includes New Physics contributions as well Summer 2006 (r, h) with NP allowed Four “independent” observables CBd, Bd, CBs, Bs CBq=1, Bq=0 in SM For the neutral kaon mixing case, it is convenient to introduce only one parameter Using Tree-level processes assumed to be NP-free *the effect in the D0-D0 mixing is neglected 5 additional parameters

The r-h plane in 2014 allowing for NP in the mixing Without LHCb With LHCb at L=10 fb-1 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

Measuring New Physics in the Bs mixing End of Tevatron Dramatic impact of LHCb on the Bs 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 Bs mixing will be known three times better than in the Bd by 2014 without the need of improvements from theory With LHCb at L=10 fb-1 in 2014 As far as CBd and CBs are concerned, they are dominated by theory  no great impact from LHCb measurements (CBs)~0.06 (CBd)~0.09

Interpretation of s vs sin2 Most precise measurements today available are Dmd/Dms, sin2b and |Vub/Vcb| A disagreement between Dmd/Dms and g 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 Bd mixing phase, it is instead important to compare sin2b with |Vub/Vcb| but need to heavily rely on Lattice QCD, interpretation in case of slight disagreement not trivial Example: current UT fits show slight disagreement between sin2b and |Vub/Vcb|, due to excess of Vub-inclusive / defect of sin2b (JHEP 0610 (2006) 081) First NP hint or theory problem in Vub? No such interpretation problems for s, just go and measure it ! If different from -0.037±0.002, NP is there

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 Bs 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 sin2b, NP might show up very early just with the first year of data in 2008 After “LHCb phase I”, in 2014, NP in the Bs mixing will be more constrained than in the Bd Other big milestones from LHCb, not impacting on CKM fits or not considered in this talk Radiative and rare decays BdK*g, Bsfg, BdK*mm, Bsmm bsss penguins e.g. Bsff Bhh’ Charm physics, ...

Backup

The LHC beauty experiment Forward-backward correlation of bb angular distribution - b Single-arm forward spectrometer, acceptance: 15-300 mrad b Tracking: Vertex Locator, TT, T1, T2, T3 PID: 2 RICH detectors, SPD/PS, ECAL, HCAL, Muon stations b b Interaction point Pythia 100μb 230μb η of B-hadron PT of B-hadron ~1 cm B pp at 14 TeV “b-factory” Luminosity at IP8 = 2·1032 cm-2s-1 1012 bb produced per year including all b-hadrons species

LHCb Calorimeter 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 p0, and multiplicity) Kinematic measurements for g and p0 with sE/E = Particle ID information for e, g, and p0. 10%  1% E

p0 reconstruction at LHCb Resolved p0: reconstructed from 2 isolated photons sm = 10 MeV/c2 Merged p0: 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. sm = 15 MeV/c2 Reconstruction efficiency: ep0 = 53 % for B0p+p-p0 Resolved π0 Merged π0 Merged Resolved Transverse energy (GeV) e π0 mass (Mev/c²)

Tree level determination of  from B±D(*)0K(*)± u B- c s K- Vcb W l Interference if same D0 and D0 final states Favoured GLW (Gronau,London,Wyler) Uses CP eigenstates of D0 decays D0 ADS (Atwood, Dunietz, Soni) b u B- K- c s W D 0 Vub = |Vub | e-ig Colour suppressed Dalitz Method – GGSZ analyze D0 three-body decays on the Dalitz plane strong amplitude (the same for Vub and Vcb mediated transitions Break-through of B-factories, but statistically limited and extremely challenging! strong phase difference between Vub and Vcb mediated transitions rB is a crucial parameter - the sensitivity on  depends on it

Bounds on NP size and phase Bd Bs 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 Bs mixing

the CKM picture, but rather as a «correction» MFV or not MFV? 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» 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 Bd sector and perform precise measurement in the Bs sector (mixing phase still largely unknown)

LHCb sensitivity: summary 2010 L=2 fb-1 2014 L=10 fb-1  4.2° 2.4° sin2 0.02 0.009  from ()° only 10° 7° s 0.021 s/s 0.004

Pre-LHCb: B-factories and Tevatron at end of their life, 2008-2009 Perspectives up to 2014 Pre-LHCb 2010 2014  6.5° 3.5° 2.3° sin2 0.017 0.013 0.008  5.4° 4.8° s 0.2 0.021 0.009 s/s 0.04 0.004 Pre-LHCb: B-factories and Tevatron at end of their life, 2008-2009