Recent CP Violation Results from the B Factories and their Implications on the CKM Paradigm B Physics and CP Violaton Andreas Hcker LAL - Orsay Mainz Seminar November 20, 2002 Reference for updated plots:Tame the Penguin and Determine ( ) ( ) J. Charles99 B Physics and the CP-Violating CKM Phase Neutral B d and B s Mixing Detection of Rare Decays: Determination of weak phases Search for new physics and direct CPV Precise Determination of the Matrix Elements |V ub | and |V cb | CP Violation (CPV) in B and K Systems: CPV in interference of decays with and without mixing CPV in mixing CPV in interference between decay amplitudes 22 11 33 CP Violation in the Standard Model Local SU(2) invariance of L SM with doublets ( iL, l iL ), (u iL, d iL ), i=1..3 gives rise to charged weak currents Mass terms: require scalar doublet ( 1, 2 ) Spontaneous symmetry breaking leads to 3 x 3 quark mass matrices Unitary rotation from mass to flavour eigenstates via Modifies L SM for charged weak currents: CKM Matrix Kobayashi, Maskawa 1973 The Cabibbo-Kobayashi-Maskawa Matrix Mass eigenstates Flavor eigenstates Quark mixing B and K mesons decay weakly Wolfenstein Parameterization (expansion in ~ 0.2): CPV phase V CKM unitary and complex 4 real parameters. (3 angles and 1 phase) (phase invariant!) Jarlskog 1985 Kobayashi, Maskawa 1973 Explicit CPV in SM, if: modified couplings for charged weak currents: B sector:K sector: Expect large CP-violating effects in B-System The Unitarity Triangle RtRt RuRu Tree processes Loop processes (mixing,...) New Physics? J /2 What is the value of in our world ? Many Ways Lead to the Unitarity Triangle J Point of Knowledge : SM or new phases (fields)? Wolfenstein-Parameters: = |V us | A = |V cb | / 2 0.83 0.05 ( , ) not well known , -plane Can we describe all observables with one unique set of, A, , ? The Experimental Program The CKM Matrix: Impact of (mostly) K Physics Observables CKM Parameters ( ) Experimental Sources Theoretical Uncertainties Quality |V ud | |V us | nuclear decay K +(0) +(0) e small KK (1 ) 1 K 0 + , 0 0 B K, cc / K K 0 + , 0 0 B 6, B 8 ? Im 2 [V* ts V td...] ( 2 A) 4 2 K 0 L 0 small (but: ( 2 A) 4 ) ( ) |V td | (1 ) 2 + 2 K + + charm loop (and: ( 2 A) 4 ) ( ) NA48 ( ) Observables may also depend on and A - not always explicitly noted see recent seminar of Prof. Kleinknecht The Quest for CP Violation in the B System ATLASATLAS CLEO 3 BELLE 2005 ? A Worldwide Effort - Testing the Standard Model: BTEV The CKM Matrix: Impact of B (d) Physics Observables CKM Parameters ( ) Experimental Sources Theoretical Uncertainties Quality m d (|V td |)(1 ) 2 + 2 B d B d f + f + X, X RECO fBdBdfBdBd m s (|V ts |) A B s f + + X = f B s B s /f B d B d sin2 , B d cc sd, ss sd small sin2 , B d + ( + ) , + SU(2) , B DK small b u, Direct CPV Strong phases, penguins ? |V cb |A b cl (excl. / incl.) F D* (1) / OPE |V ub | 2 + 2 b ul (excl. / incl.) Model / OPE |V td | (1 ) 2 + 2 Bd Bd Model (QCD FA)? |V ts |NP B d X s (K ( ) ) , K ( ) l + l (FCNC) Model? |V ub |, f Bd 2 + 2 B + + fBdfBd ( ) Observables may also depend on and A - not always explicitly noted Linac Fixed Target Experiments BABAR SLD (& MARK II) ee e+e+ The Asymmetric B-Meson Factory PEP-II: 9 GeV e on 3.1 GeV e + : coherent neutral B pair production and decay (p-wave) boost of (4S) in lab frame : = 0.56 BABAR and Belle: Integrated Luminosity Belle just passed 100 fb 1 ~ 113 million BB pairs B A B AR BelleBelle SVT97% efficiency, m z resolution Tracking (p T )/p T = 0.13% p T 0.45% DIRC K- separation > 3.4 for p < 3.5 GeV/c EMC E /E = 1.3% E 1/4 2.1% Particle Identification for B A B AR : the DIRC erenkov Detector Detection of Internally Reflected erenkov light Excellent /K/p separation up to 4 GeV/c The DIRC Principle: Time-Integrated Measurements Determination of the Matrix Elements |V cb | and |V ub | For both, |V cb | and |V ub |, exist exclusive and inclusive semileptonic approaches. The theoretical tools are Heavy Quark Effective Theory (HQET) and the Operator Product Expansion (OPE), respectively. Symmetry of heavy quarks [=SU(2n Q )]: in the limit m Q of a Qq system, the heavy quark represents a static color source with fixed 4-momentum the light degrees of freedom become insensitive to spin and flavor of the heavy quark |V ub | ( 2 + 2 ) is crucial for the SM prediction of sin(2 ) |V cb | ( A) is important for the interpret. of kaon physics ( K, BR(K ), ) See the very pedagogical talk given by M. Luke at FPCP02:1/ QCD Compton wavelength b m b 1 Fermi motion Measurement of rate as fct. of momentum transition Determination of |V cb | from extrapolation to 1 (theory is most restrictive) Exclusive Semileptonic B D l DecaysBelleBelle in B rest system is = (D ) Bigi; Uraltsev; Neubert;... Lattice QCD: Hashimoto et al. [hep-ph/ ] Belle, PLB 526, 247 (2002) =1 =1.5 OPE shows that for, inclusive B decay rates are equal to b quark decay rates. Corrections are suppressed by and. Inclusive Semileptonic B X c l Decays Bigi, Shifman, Uraltsev; Hoang, Ligeti, Manohar,... A promising approach for a theoretically improved analysis is the combined fit of the HQET parameters und 1 (CLEO) to mass and lepton moments or to b s . Allows to directly probe Quark-Hadron Duality successful in decays Bauer et al., hep-ex/ [using BABAR, CLEO, DELPHI data] 0.4 0.3 0.2 0 0.1 |V cb | (40.9 0.9) 10 3 1 CLEO |V ub | from exclusive Decays (I) Pure tree decay. Decay rate is proportional to CKM element |V ub | 2 Would need unquenched lattice calculation to become model- independent... CLEO, Phys.Rev.D61:052001,2000; BABAR hep-ex/ BABARBABAR Problem: form factor is model dependent ! | V ub | from inclusive Decays free quark decaynonperturbative corrections Good: relation between & |V ub | known to ~5% Bad: cannot be measured fully inclusively, since need to impose stringent cuts to eliminate charm background hadronic invariant mass spectrum for b u decay kinematic limit for b c parton model including Fermi motion (model) ... and here the troubles begin (M. Luke, FPCP02) only b u | V ub | from inclusive Decays Suppression of the dominant charm background by cutting on the B X u l lepton momentum beyond the kinematic limit of B X c l Reduction of model dependence by using HQE and the shape function measured in B X s CLEOCLEO Validity of quark-hadron duality? (stat)(fu)(HQE)(1/m b ) CLEO, hep-ex/ B Xs B Xs SM fit > 5% CL Measurement of the whole spectrum ( Theorie under control) B X u l (Neural Net for Signal) (exp) (bu)(bu) (HQE) bb (bc)(bc) LEP |V ub | Working group Problem: strong model dependence of |V ub | Knowledge of b c background; inclusive measurement ? Time-Dependent Measurements B 0 B 0 Mixing: Principle Schrdinger equation governs time evolution of B 0 -B 0 System: with mass eigenstates: Defining: One obtains for the time-dependent asymmetry: where::and: B 0 B 0 Mixing (Theory) Effective FCNC Processes (CP conserving): whose oscillation frequencies m d/s are computed by: Perturbative QCD Lattice QCD (eff. 4 fermion operator) CKM Matrix Elements Important theoretical uncertainties: d/s B0B0 B0B0 b WW t t b [ B=2] Improved error from m s measurement: B 0 B 0 Mixing (Experiment) B-Flavor Tagging Exclusive B Recon- struction (flavor eigenstates) lifetime, mixing analyses (CP eigenstates) CP analysis (4S) t z/ c z 250 m Experimental Technique: BABAR PRD 66 (2002) B A B AR B 0 B 0 Mixing using Flavour Eigenstates Mistag probabilityDetector Resolution B s 0 B s 0 Mixing Preferred value is 17.2 ps 1, but only limit exploitable in CKM fit m s not yet measured --- powerful lower limit --- waiting for TEVATRON Amplitude spectrum: LEP/SLD/CDF excluded at 95% CL Theoretical uncertainty SM fit Experimental error > 5% CL SM fit Improvement from m s limit > 5% CL Constraints from m d and m s Waiting for a m s measurment at Tevatron... Time-dependent CP Observables: CP violation arises from interference between decays with and without mixing: CP mixing decay CP eigenvalue amplitude ratio = 0 = sin(2 ) Time-dependent CP Asymmetry for b ccs, sss and with: Single weak phase: clean extraction of CP phase no direct CPV: The Golden Channel: top-quark dominates Tree Diagram Penguins Time-dependent CP Asymmetry: sin2 CP = 1 CP Violation established in the B system ! more on time-dependent CP asymmetries later... BABAR hep-ex/ B A B AR 81.3 fb -1 B A B AR 81.3 fb -1 null measurement for comparison: using B flav sample in fit sin2 BABAR OPAL ALEPH CDF BELLE World average sin2 : World Average hep-ex/ hep-ex/ Results improved by more than just the luminosity gain Million BB pairs July 00 Feb 01 July 01 Mar 02 July 02 B A B AR Putting all together Metrology in the ( , ) Plane. Region of > 5% CL Standard Constraints (not including sin2 ) Standard Constraints (not including sin2 ) status: ICHEP02 Metrology Standard Constraints (not including sin2 ) Standard Constraints (not including sin2 ) A TRIUMPH FOR THE STANDARD MODEL AND THE KM PARADIGM ! KM mechanism most probably the dominant source of CPV at EW scale Still true??? status: ICHEP02 Both decays dominated by single weak phase Metrology BABAR, hep-ex/ Belle, hep-ex/ Penguin: Tree: New CP Results from complemen- tary modes: New Physics ? status: ICHEP02 Metrology Standard Constraints (including sin2 ) Standard Constraints (including sin2 ) sin2 already provides one of the most precise and robust constraints How to im- prove these con- straints? How to mea- sure the missing angles ?... status: ICHEP02 Metrology in the (sin2 , sin2 ) Plane. Standard Constraints (not including sin2 ) Standard Constraints (not including sin2 ) status: FPCP02 We Need More Information ! Rare charmless B Decays We Need More Information ! Rare charmless B Decays Rare Charmless B Decays Semileptonic (FCNC) and radiative decays (G F ) 2 increased compared to loop-induced non- radiative decays (G F ) 2 Sensitive sondes for new physics (SUSY, right-handed couplings,...) Determination of |V td | and |V ts | Determination of HQET parameters Search for direct CP asymmetry Hadronic b u(d) decays Measurement of CPV Determination of UT angles and Test der B decay dynamics (Factorization) Tree Penguin Box We distinguish two Categories: How can we detect b u(d) decays that are suppressed with |V ub /V cb | 2 0.01 ? e + e (4s) BB B Decay (almost) in rest B XuB Xu B XCB XC Kinematic Reconstruction: Selection with Event shape variables background signal CMS track momentum B-related background is small: B 2b Dominant background from e + e qq is jet-like B +B + Typical resolution: (m ES ) 2.5 MeV/c 2 ( E) MeV B A B AR Direct CP Violation in the Decay Time-integrated Observable: Interfering contributions to the decay amplitude generate direct CPV: Strong phase difference Weak phase difference For neutral Bs direct CPV competes with other CPV phenomena =0 or =0 no direct CP Violation Branching Fs. and A CP for B /K status: ICHEP02 Agreement among experiments. Most rare decay channels discovered 0.02 0.09 0.01 0.05 0.07 | | 1 must fit for direct CP Im ( ) sin(2 ) need to relate asymmetry to C = 0, S = sin(2 ) C 0, S ~ sin(2 eff ) For a single weak phase (tree):For additional phases: CP Violation in B 0 + Decays Tree diagram: Penguin diagram: CP eigenvalue ratio of amplitudes CP mixing decay Bounds/Predictions on | eff | Different Strategies: Determination of P/T by virtue of flavour symmetries (mild theoretical assumptions, eg, P EW =0) SU(2): Gronau-London Isospin Analysis Grossmann-Quinn bound (also Charles, Gonau et al.) SU(3): Fleischer-Buras, Charles (P ~ P K ) Using theoretical predictions for P/T naive Factorization (|P/T| 2 ~ BR(B + + 0 ) / BR(B + + 0 ) ) |P/T| and phase from QCD Factorization (Beneke et al.) and pQCD (Lee et al.) to be tamed... (Charles) shown here sin(2 eff ) & Isopin Analysis. Using the BRs: + , 0, 0 0 (limit) and the CP asymmetries : A CP ( 0 ), S , C and the amplitude relations: BABAR S 0.34 C 0.30 0.25 BABAR 2 2 eff status: ICHEP02 How about More Statistics? Isospin analysis for present central values, but 500 fb 1 and even more... If central value of BR( 0 0 ) stays large, isospin analysis cannot be performed by first generation B factories Input: S & C & sin(2 WA ) Input: S & C sin(2 eff ) & QCD FA |P/T| and arg(P/T) predicted by QCD FA (BBNS01) BABAR sin(2 eff ) & QCD FA Input: S & C Zoom S C Belle Input: S & C Belle: (Moriond02) no update since Moriond02 Predicting the Experimental Observables S C Only predictive approach: QCD FA...it works...yet ! Using , from standard CKM fit Where are we today What brings the future ? Where are we today What brings the future ? BABAR / Belle Similar scenario expected for Belle PEP-II Luminosity Projections 3 Global CKM fit (CKMfitter) gives consistent picture of Standard Model sin(2 ) now most accurate constraint future consistencies:BABAR Belle ? J/ K S K S m s : constraint on UT angle from LEP/SLD/CDF limit expect measurement from TEVATRON soon: sensitive to new physics! Rare K decays enter the game, but more statistics needed also: keep an eye on improving |V cb | ! Need more constraints on CKM phase: Charmless B decays and CP violation: best fits (in BBNS) around 80 Conventional isospin analysis potentially unfruitful to extract sin(2 ) Significant theoretical input needed Requires detailed study of relevant theoretical uncertainties The race for : high statistics needed for B DK( ) low theoretical inputConclusionsConclusions Summer 06: (sin2 WA ) ~ for 1000 fb 1 Many more results to come from the B-factories We know the center already quite well but there is not enough redundancy A better understan- ding/prediction of long distance QCD (lattice!) opens the shrine to a full ex- ploitation of the huge data samples currently produced at KEKB and PEPII....and the immense data quantities that will be produced at the Tevatron & LHC The Model Standard remains unscathed