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Max BaakCKM Workshop 2006, Nagoya 1 1.Introduction 2.SU(3) breaking effects Soft rescattering effects W-exchange contributions Non-factorizable contributions 3.Conclusion SU(3) breaking effects in the SU(3) determination of the amplitude ratio r D(*)h Max Baak, NIKHEF CKM Workshop 2006, Nagoya Thanks to Dan Pirjol!
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Max BaakCKM Workshop 2006, Nagoya 2 sin(2 + ) : determination of r D(*)h CP violation in B 0 D (*) / proportional to ratio r D(*)h of CKM-suppressed over CKM-favored amplitude. r D(*)h |V * ub V cd / V cb V * ud | 0.02 Measured CP-asymmetries: 2 observables, 3 unknowns: Simultaneous determination of sin(2 + ) and r D(*)h from time-evolution impossible with current statistics need r D(*)h as external inputs ! Imposssible to measure r D(*)h from BR(B + D + 0 ) (small: 5x10 -7 ) Estimate r D(*)h from B 0 D s (*)+ - / - using SU(3) symmetry [1] Using: SU(3) [1] I. Dunietz, Phys. Lett. B 427, 179 (1998)
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Max BaakCKM Workshop 2006, Nagoya 3 Caveat: possible SU(3) breaking Amplitude relation assumes factorization Not (yet) been proven to work for wrong-charm b u transitions i.e. No theoretical handle on size of non-factorizable contributions involved Three potential sources of SU(3) breaking between D (*) h and D s (*) h : 1.Unknown SU(3) breaking uncertainty from non-factorizable contributions 2.Final state interactions: different rescattering diagrams 3.Missing W-exchange diagrams in calculation Accounted for by introducing theoretical uncertainty on amplitude ratio r D(*)h Size of uncertainty not well understood Typically guestimated to be 30% of size of amplitude ratio. sin(2 + ) measurements often excluded in averages of direct measurements But: SU(3) breaking uncertainties have negligible impact on determination of gamma!
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Max BaakCKM Workshop 2006, Nagoya 4 Theoretically ‘proven’ in SCET, and using limit N c . Works experimentally at few % level for b c color-allowed decays. No theoretical proof for factorization in wrong-charm b u regime. Few wrong-charm b u measurements exist yet to indicate whether factorization applies. Factorization B. Aubert et al., Phys.Rev.D74:012001 (2006) b c transitions A.J. Buras, J-.M. Gerard, and R. Ruckl, Nucl. Phys. B268, 16 (1986) H.D. Politzer and M.B. Wise, Phys. Lett. B257, 399 (1991); M. Beneke, G. Buchalla, M. Neubert, and C.T. Sachrajda, Phys. Rev. Lett. 83, 1914 (1999); C.W. Bauer, D. Pirjol, I.W. Stewart, Phys. Rev. Lett. 87, 201806 (2001).
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Max BaakCKM Workshop 2006, Nagoya 5 Naive factorization: b u predictions In analogy of relation of CKM-favored BRs of B D (*) / to B D (*) l... No heavy quark symmetry used to obtain relations Does not include rescattering effects. B D s * (B D s * ) good test channel for factorization!
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Max BaakCKM Workshop 2006, Nagoya 6 To good approximation, form factor models linear over q 2 [0,15] GeV 2 Average of partial branching fractions over q 2 [0,8] GeV 2 gives estimate at q 2 =m 2 D(*)(s) Available B l measurements already yield good prediction for BR(B D s * ). More later... No need for both theoretical form factor predictions and large error on V ub. Results from B l q 2 [GeV 2 ] BaBar CLEO Belle 10 4 B d /dq 2 [GeV -2 ] T. Becher and R.J. Hill, Phys. Lett. B633, 61 (2006) Becirevic-Kaidalov FF model
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Max BaakCKM Workshop 2006, Nagoya 7 Final state interactions (FSI) Rescattering effects need not be suppressed at m B scale. [1] Large rescattering suggested by large BFs of color-suppressed decays B 0 D (*)0 0 / 0 / Example of SU(3) breaking rescattering diagram in r D(*)h : No such “annihilation rescattering” for final state D s / Rescattering amplitudes hard to calculate. Interactions occur after hadron formation: i.e. rescattering amplitudes after CKM- favored decays B 0 D - + same as after CKM-suppressed decays B 0 D - + Obtain rescattering amplitudes from CKM-favored decays! [1] J.F. Donoghue et al., Phys. Rev. Lett. 77, 2178 (1996)
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Max BaakCKM Workshop 2006, Nagoya 8 Quasi-elastic rescattering Framework developed by C.-K. Chua, W.-S. Hou, and K.-C. Yang [1] Aim: seperate long-distance rescattering effects from ‘shorter’- distance interactions Rescattering occurs at m B >> m q (q=u,d,s): amplitudes should respect SU(3) to good degree. Extend rescattering between isospin-states to quasi-elastic rescattering between SU(3) states. 3 possible types of rescattering: (c-quark left unchanged) 1. quark exchange: r e 2. quark annihilation: r a 3. gluon exchange: r 0 [1] Chua, Hou, Yang, Phys. Rev. D65: 096007, 2002.
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Max BaakCKM Workshop 2006, Nagoya 9 Example rescattering matrix Strong interactions rescattering matrix: Decompose: ’ falls outside SU(3) octet independent rescattering amplitudes for D (*) ’ Similar rescattering matrices for B D * P and B DV modes. T, C, E: ‘bare’ tree, color-suppressed, W-exchange amplitudes. Calculate T amplitude using factorization. Fit for C (a 2 ) and E amplitudes. Fit model requires many input parameters (masses, form factors, decay constants, CKM-constants). See backup slides for numbers used. Rescattering matrix for B DP Bare decay amplitudes X
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Max BaakCKM Workshop 2006, Nagoya 10 Fit parameters of S Change of parameters to facilitate calculation of S 1/2 : To obtain S 1/2, divide all phases by two: r i r i ’ Fit Parameters # D P / D * P rescattering angles3 D V rescattering angle1 a 2 Wilson param. (col.-sup.)1 W-exchange amplitudes3 - ’ mixing angle (fixed) - Free parameters8 BR measurements26 DP, D * P, DV No annihilation rescattering for B DV 1. 2. [1] Chua, Hou, Yang, Phys. Rev. D65: 096007, 2002. zero phases: no rescattering
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Max BaakCKM Workshop 2006, Nagoya 11 Fit results 1 Good agreement between all rescattering predictions and measured branching fractions. Fac.: 2 = 351.3 Fac.+Resc.: 2 /d.o.f. = 18.2/18 Rescattering contributions dominate color-suppressed BRs. Fit consistent with single a 2 for all color-suppressed amplitudes C. Value of a 2 (0.22 0.02) consistent with naive factorization. (a 1 1.02) Good predictive power! PRD65, 096007 (2002) already made correct predictions for B D s (*) K, D (*)0 K (*) BR (x10 -4 )
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Max BaakCKM Workshop 2006, Nagoya 12 Fit results 2 Cross checks: Rescattering angles found compatible with Chua, Hou, Yang [1] Fit for a 1 : 1.06 0.03 (fixed: 1.02) Fit for eta-eta’ mixing angle : -20 28 (fixed: -16) [1] Chua, Hou, Yang, Phys. Rev. D65: 096007, 2002.
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Max BaakCKM Workshop 2006, Nagoya 13 BR predictions for b u decays Assuming naive factorization and rescattering results... Ignoring possible non- factorizable contributions. Large rescattering contributions to B + D (*)0 K (*)+ large rescattering phases. Good agreement within errors. Form-factor uncertainties dominant for most BR predictions. B 0 D s * : ‘golden’ decay channel to determine size of non-factorizable contributions! Low BR(B 0 D s ) explained BaBar Belle BR (x10 -5 )
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Max BaakCKM Workshop 2006, Nagoya 14 SU(3) correction from rescattering More b u decays (V cd ) Hardly any rescattering contributions from color-suppressed decays to color- allowed decays. i.e. To good approximation, color-allowed BRs only affected by diagonal rescattering matrix elements Naive amplitude ratio : SU(3) rescattering correction factor R i to amplitude ratio r D(*)h : Values of R i : 1. No annihilation rescattering for B 0 h - D s (*)+ 2. Kinematic factor
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Max BaakCKM Workshop 2006, Nagoya 15 W-exchange amplitudes SU(3) breaking error on r[D (*) h] from missing exchange diagram: Ignores rescattering contribution to D s K overestimation of E W-exchange amplitudes from rescattering fit consistent with naive factorization estimates! No exchange diagram for final state D s / b u transition Large uncertainty on |E/T| estimate for b u transition: 1.Factorization uncertainty for b u 2.Value of Callan-Treiman prediction: |E/T|<5.0% Add 200% error on predicted ratio: b c transition
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Max BaakCKM Workshop 2006, Nagoya 16 Non-factorizable b u contributions Relative size of non-factorizable amplitude: Limit should improve with updates of: BR(B l ), BR(B 0 - D s *+ ), f Ds. Two definitions to describe SU(3) breaking from non-factorizable corrections: typical SU(3) perturbation parameter SU(3) breaking parameter in amplitude ratio r D(*)h (contains 1 unit of 2m s / ) 1. 2.
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Max BaakCKM Workshop 2006, Nagoya 17 Non-factorizable SU(3) breaking SU(3) breaking in amplitude ratio r from non-factorizable contributions: Additional SU(3) breaking proportional to non-factorizable contributions times perturbation parameter Assuming up to 3 times typical SU(3) breaking scale for B 0 - D (s) *+ : < 0.17 @ 68.3% CL Absorbs one unit of 2m s / Non-factorizable amplitude B 0 h - D (*)+
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Max BaakCKM Workshop 2006, Nagoya 18 Amplitude ratios Amplitude ratios after rescattering correction: New since PDG ‘06: large uncertaintainty from V cs We add 9% Gaussian errors for SU(3) from non- factorizable contributions and 5% flat errors for SU(3) breaking from W-exchange diagrams. No SU(3) uncertainties included
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Max BaakCKM Workshop 2006, Nagoya 19 Impact on Extraction dominated by experimental uncertainties Improved SU(3) breaking errors have negligible impact on determination of ! With SU(3) breaking: [-0.28,1.91] rad @ 90% CL No SU(3) breaking: [-0.27,1.90] rad @ 90% CL HFAG ICHEP 2006: a,c CP asymmetries CKMfitter frequentist recipe 3 SU(3) breaking error scenarios f: flat error g: Gaussian error [rad]
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Max BaakCKM Workshop 2006, Nagoya 20 Conclusions Improved SU(3) breaking uncertainties have negligible impact on determination of ! Partial branching fractions of B l provide good handle on non-factorizable contributions to B 0 - D s *+ Soft rescattering amplitudes can be determined precisely from CKM-favored decays B D (*) and B D using a quasi-elastic rescattering framework. Small SU(3) breaking corrections to r D(*)h. Simple use of BR(B 0 D s - + ) gives overestimate of E/T. Naive conversion ignores dominant contribution from rescattering. Estimates of E from rescattering fit consistent with naive factorization estimates. |E/T| < 5% SU(3) breaking uncertainty to r D(*)h from non-factorizable contributions suppressed with SU(3) perturbation scale uncertainty < 9% @ 68% CL Include sin(2 + ) measurements in world average of !
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Max BaakCKM Workshop 2006, Nagoya 21 CP violation in B 0 D (*) / CP violation through B 0 -B 0 mixing and interference of amplitudes: Large BF’s, at level of 1% No penguin pollution theoretically clean CP violation proportional to ratio r D(*)h of amplitudes Small: r D(*)h |V * ub V cd / V cb V * ud | 0.020 Relative weak phase from b u transition Relative strong phase Strong phase difference CKM Unitarity Triangle Favored amplitude Suppressed amplitude through b u transition u,c,t
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Max BaakCKM Workshop 2006, Nagoya 22 World Average CP-asymmetries 3.4 CP violation in B 0 D * ! The only solution with is statistics... HFAG ICHEP 2006 Pity to ignore these measurements!
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Max BaakCKM Workshop 2006, Nagoya 23 Rescattering formalism 1.Time-reversal operator gives rescattering relation: 2.Strong interactions rescattering matrix S 3.Rescattering relation can formally be solved as: A i b represent real, ‘bare’ decay amplitudes – in absence of rescattering effects. For A i b we test the predictions from naive factorization
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Max BaakCKM Workshop 2006, Nagoya 24 Linearity FF models B l B l
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Max BaakCKM Workshop 2006, Nagoya 25 SU(3) breaking in B D (s) (*) D (*)
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Max BaakCKM Workshop 2006, Nagoya 26 Decay Constants 1 Alle numbers taken from PDG06 where possible... From factor values from: - Melikhov & Stech - Braun & Zwicky - Ball
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Max BaakCKM Workshop 2006, Nagoya 27 Decay Constants 2 Callan-Treiman relation
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