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Measurements of sin(2 b + g ) / sin(2 f 1 + f 3 )

Results from. and. Belle. BaBar. Measurements of sin(2 b + g ) / sin(2 f 1 + f 3 ). Guillaume Therin LPNHE – Paris XL ème rencontres de Moriond. *. V td V tb. *. V ud V ub. *. V cd V cb. CP violation in standard model. Talk on time dependent analysis to constraint sin(2 b+g )

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Measurements of sin(2 b + g ) / sin(2 f 1 + f 3 )

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  1. Results from and Belle BaBar Measurements of sin(2b + g) / sin(2f1 + f3) Guillaume Therin LPNHE – Paris XLème rencontres de Moriond Measurements of sin(2b+g)

  2. * VtdVtb * VudVub * VcdVcb CP violation in standard model • Talk on time dependent analysis to constraint sin(2b+g) • Experimental results on B0 D(*) p/r • Partial reconstruction • Full reconstruction • B0 D(*)0K(*)0 branching ratio Unitarity triangle CKM matrix a/f2 g/f3 b/f1 sin (2b) = 0.725 ± 0.037 HFAG ICHEP04 Experimental constraints on a Need direct measurements of g See P.Krokovny’s talk for a review of g measurements. http://ckmfitter.in2p3.fr Measurements of sin(2b+g)

  3. p+/r+ p+/r+ A(B0 → D(*)- p+) ≈ 0.02 r(D(*)p) ≡ r(*) = A(B0 → D(*)- p+) CP violation in B0D(*)p/r • Large branching fraction for favoured decay (~3x 10-3) • Small BR for suppressed decay (~10-6) • Small CP violating amplitude 2b g Suppressed b u decay Favored b c decay Strong phase difference CKMangle Determines the sensitivityof the method Measurements of sin(2b+g)

  4. < ~ 1 – r2 C = ≈ 1 l+ 1 + r2 S± ≈2r sin ( 2b+g±d ) , |S±| 0.04 K+ Time-dependent decay rate distributions - K+ -s Tag B K+ U(4s) Reco B z + Dt @Dz/gbc Dz Mixing-Decay interference ∞ ± ± ± P(B0 → D(*)p ,Dt) 1 C cos(DmdDt) + S sin(DmdDt) ± ± ∞ ± P(B0 → D(*)p ,Dt) 1 C cos(DmdDt) - S sin(DmdDt) ± ± neglecting terms in o(r2) Measurements of S+ and S- determine 2b+g and d if r is an external input Experiment : tag the flavour of the B with lepton and kaon categories lepton tag kaon tag Measurements of sin(2b+g)

  5. ∞ K+ K+ ’ Possible CP violation on the tag side Long, Baak, Cahn, Kirkby, PRD68, 034010 Potential competing CP violating effects in B decays used for flavour tagging + Kaon tag : expect CP violation comparable to signal → Modified time distributions signal side tag side P(B0 → D(*) -p+ ,Dt) 1 +C cos(DmdDt) + sin(DmdDt) [± 2r sin(2b+g+d) +2r’ sin(2b+g±d’)] Kaon and other flavour tags Lepton tags Observables : S+, S- Observables a, b, c Measurements of sin(2b+g)

  6. SU(3) r(D) = 0.020 ± 0.003 r(D*) = 0.015 ± 0.005 r(Dr) = 0.003 ± 0.006 Determination of r I. Dunietz, Phys. Lett. B 427, 179 (1998) • Simultaneous determination of sin(2+) and rfrom time-evolution is not possible with current statistics  Need r as external inputs • Estimate amplitude ratios from B0Ds(*)+- using SU(3) symmetry Assuming several hypotheses : • Assuming factorisation in SU(3) symmetry • W-exchange and annihilation diagrams neglected without any theoritical errors Measurements of sin(2b+g)

  7. fast Signal D*r Combinatoric BB Peaking BB Continuum N(B0 tag) + N(B0 tag) N(B0 tag) - N(B0 tag) ACP= B0→D*-p+: partial reconstruction Babar BaBar Collaboration,hep-ex/0408038 (previous reference) 227MBB Lepton Tags Find events with two pions and examine the missing mass mmiss Preliminary All available statistics Preliminary kaon Tags Preliminary Lepton Tags Mean value 18710 ± 270 lepton tags 70580 ± 660 kaon tags Measurements of sin(2b+g)

  8. B0→D*-p+: partial reconstruction (interpretation) Babar BaBar Collaboration,hep-ex/0408038 (previous reference) 227MBB Adding 30% theoretical error on r(D*p) for different hypotheses Using the Feldman Cousins method r-h plane whith experimental constraints on sin(2β+γ) andβ(from BaBar). r = 0.015 ± 0.005 ±0.005 Preliminary 1 - CL 68 % 90 % Preliminary |sin(2β+γ)|>0.62 (0.35) @ 68 (90)%CL Measurements of sin(2b+g)

  9. B0→D*-p+: partial reconstruction (lepton tag) Belle Collaboration,hep-ex/0408106 154MBB SF : Sign(pfast) = Sign(l) OF : Sign(pfast) = - Sign(l) Preliminary Preliminary Preliminary Preliminary Preliminary Preliminary helicity angle calculated with psoft Fit : Signal +Background 2823 Same Flavour (SF) 10078 Opposite Flavour (OF) S+ = 0.035 ± 0.041 ± 0.018 S- = 0.025 ± 0.041 ± 0.018 Measurements of sin(2b+g)

  10. Babar 110MBB B0→D(*)-p+/r+: full reconstruction BaBar Collaboration,hep-ex/0408106 D*- p+ D*+ p- ± ± B → D* p D*- p+ D*+ p- 7611 ± 97 B → Dp 7068 ± 89 B → D*p 4400 ± 79 B → Dr Measurements of sin(2b+g)

  11. 154MBB B0→D(*)-p+: full reconstruction Belle Collaboration, PRL 93 (2004) 031802 Dp D*p Use kaon and lepton tags Estimation of CP violation on the tag side with B→D*l n D*+ p- D*- p+ Assuming δ = 0 or π (factorisation) : D*+ p- D*- p+ Measurements of sin(2b+g)

  12. r(D) = 0.020 ± 0.003 r(D*) = 0.015 ± 0.005 r(Dr) = 0.003 ± 0.006 Summary of sin(2b+g)results with B0 → D(*)p/r 227 MBB 110 MBB 152 MBB 152 MBB Partially rec. Fully rec. Partially rec. Fully rec. 0.060 ± 0.040 ± 0.019 a(D*p) –0.049 ± 0.031 ± 0.020 -0.034 ± 0.014 ± 0.009 –0.031 ± 0.028 ± 0.018 c(D*p) –0.004 ± 0.028 ± 0.018 -0.019 ± 0.022 ± 0.013 0.044 ± 0.054 ± 0.033 0.049 ± 0.040 ± 0.019 a(Dp) –0.032 ± 0.031 ± 0.020 –0.062 ± 0.037 ± 0.018 c(Dp) –0.025 ± 0.037 ± 0.018 –0.059 ± 0.055 ± 0.033 a(Dr) –0.005 ± 0.044 ± 0.021 c(Dr) –0.147 ± 0.074 ± 0.035 a = 2 r sin(2b+g) cos (di) c = 2 r cos(2b+g) sin (di) without any errors coming from theoretical hypotheses Measurements of sin(2b+g)

  13. Interpretation of sin(2b+g) assuming SU(3) Assign 30 % theoretical error on r(D*p), r(Dp) and r(Dr) Bayesian approach www.utfit.org h 68 % 90 % 68 % 90 % r 2b+g |sin(2b+g)|>0.74 @68% CL Measurements of sin(2b+g)

  14. A(B0 → D0 K0) ≈ 0.4 r0 = A(B0 → D0 K0) Constraining sin(2b+g) with B0→D(*)0Ks • Small branching fraction for favoured decay (~3x 10-5) • Large asymmetry • B0D(*)0Ks with any D0 measures sin2b+g with time dependent analysis • B0D(*)0K*0 with D0CP eigenstate measures g (self-tagging mode ,not this talk) bcamplitude bu amplitude For r0=0.4, an error of 0.5 on sin(2b+g) is expected with 550 MBB . Measurements of sin(2b+g)

  15. Babar 274MBB 124MBB D0 mass sideband B( ) = 6.2 ± 1.2 ± 0.4 B0 → D0 K0 B( ) = 3.72 ± 0.65 ± 0.37 +1.25 B( ) = 3.18 ± 0.32 B0 → D*0 K0 -1.12 B → D0 K0 r0( ) <0.39 @ 90% B( ) = 4.5 ± 1.9 ± 0.5 B → D*0 K0 D0 K*0 Branching ratios of B0→D(*)0Ks Preliminary mes (GeV) BaBar Collaboration,hep-ex/0408052 Belle Collaboration,hep-ex/0408108 Average of B0 and B0 Measurements of sin(2b+g)

  16. Conclusions • Many different approaches to measure g have been investigated with similar sensitivity. • Limits on | sin(2b+g)| with time dependent analysis were updated • Measurements on sin(2b+g)still statistics limited. • Some analyses need to be updated with all available statistics • Need to estimate CP violation on the tag side to use completely kaon tag • Results on g can be combined with other DK measurements (also no penguin contribution) • With higher statistics, methods to constraint sin(2b+g) with B0 → D(*)0 Ks will play a role as well ( r ≈ 0.4 ) |sin(2b+g)|>0.74 @68% CL Assuming SU(3) symmetry www.utfit.org Measurements of sin(2b+g)

  17. SU(3) breaking and Dsp0 • SU(3) has been proven to hold at a few % level for factorizable processes, but here the heavy meson is emitted and factorization does not hold • Note that the use of the form-factors automatically assumes factorization • In the future BR(D+p0) will be measured • expected to be ~10-6 • SU(2) partner of D+p- • SU(3) partner of Dsp0 will be able to test SU(3) • First search of BDsp0 • Consistent with SU(2) prediction from Br(Dsp ) • Br(BDsp0) = 1.6 10-5 Small statistics Annihilations around Br(BDsp0)<2.8 10-5@90% C.L. Measurements of sin(2b+g)

  18. d,s d,s W-exchange diagrams B0D(*)+p- has contributions also from W exchange Constrained by smallness of Br(B0Ds-K+)/Br(B0D-p+)=(1.4±0.5)10-2 c D(*)-, Ds(*)- p+,K+ u Unfortunately this sets a limit only on the annihilation on the cabibbo allowed process. Assuming it is the same is controversial Measurements of sin(2b+g)

  19. D(*)+Ks : probing annihilations SU(2) partner of D0K+ Expected to be ~10-7 but could get large contributions from rescattering Br(B D+Ks) < xxx 10-6 Br(B D*+Ks) < 7 10-6 Note: Br(B D0K+) =(3.7±0.6)10-4 Br(B D*0K+)=(3.6±1.0)10-4 Measurements of sin(2b+g)

  20. mixing D±K*± → Avoiding colour suppression : B0→D±KSp±(88 MBB) • Method has two advantages : • Avoids colour suppression in b→u • Integrating over Dalitz plane removes ambiguities in eventual g extraction • First experimental step complete : • Branching fraction measurement • Currently, Too few events for TD analysis • 1/3 of events are NOT in the K* region bcamplitude bu amplitude Measurements of sin(2b+g)

  21. 350 fb-1 integrated luminosity 275 million BB events 254 fb-1integrated luminosity 227 million BB events Data samples collected with Belle and BaBar BELLE @ KEK-B Accelerator BaBar @ PEP-II Accelerator Measurements of sin(2b+g)

  22. sin(2b+g) in Pictures • r exaggerated (x5 expectation) to enhance visual effect • Small values of r significantly reduce sensitivity of the method No Interference  CP Violation CP Violation only in fully reconstructed B0: r  0 CP Violation in both tag and fully reconstructed B0s: r  0 and r’  0 Measurements of sin(2b+g)

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