4 research outputs found

    SU(3) Corrections to B -> D l nu Form Factors at O(1/M)

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    We compute the O(1/M,m_s) heavy quark and SU(3) corrections to B_s -> D_s e nu form factors. In the limit of vanishing light quark mass, B_s -> D_s e nu form factors are given in terms of the the B -> D e nu form factors, the leading order chiral parameter g, and two O(1/M) chiral parameters g1g_1 and g2g_2. All the chiral parameters can be extracted, in principle, from other heavy meson decays. Analytic counterterms proportional to the strange quark mass are presented for completeness, but no predictive power remains when they are included. Anomalously large loop corrections warn of poor convergence of the heavy quark chiral symmetry expansion for these processes. This suggests that naive extrapolations of B \to D form factors relying on heavy quark and chiral symmetries, as often used in monte carlo simulations of lattice QCD, may incur large errors.Comment: uuencoded, 24 pages, 6 eps figures, uses lanlmac/harvmac (suggest `b' size) and epsf.tex (if you want auto-insertion of figs)

    Chiral and Heavy Quark Symmetry Violation in B Decays

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    The most general Lagrangian consistent with chiral, heavy quark, and strong interaction symmetries to order 1/M1/M and to linear order in the SU(3) vector and axial currents is presented. Two new dimensionful and five dimensionless couplings arise at this order. The heavy to light flavor changing current is derived to the same order, giving rise to two additional dimensionful constants and six dimensionless ones. The dimensionless parameters are shown to be irrelevant at \ord. The leading nonanalytic heavy quark and chiral symmetry violating corrections to heavy meson decay constants are computed, and implications to B decays are discussed; measurements of the experimentally accessible form factors for D→πlνD \to \pi l \nu and B→πlνB \to \pi l \nu, along with knowledge of the D∗DπD^* D \pi coupling, determine the eight decay constants fDf_D, fDsf_{D_s}, fD∗f_{D^*}, fDs∗f_{D_s^*}, fBf_B, fBs f_{B_s}, fB∗f_{B^*}, and fBs∗f_{B_s^*}, as well as one relation among the B→πlνB \to \pi l \nu form factors, to \ord~. The ratio R1=fBsfB/fDsfDR_1 = \frac{f_{B_s}}{f_B}/\frac{f_{D_s}}{f_D} is expressed in terms of two dimensionful couplings.Comment: 22 pages, harvmac, 5 eps figs, resubmitted for automated postscrip

    Radiative D∗D^* Decay Using Heavy Quark and Chiral Symmetry

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    The implications of chiral SU(3)L×SU(3)RSU(3)_L \times SU(3)_R symmetry and heavy quark symmetry for the radiative decays D∗0→D0γD^{*0}\to D^0\gamma, D∗+→D+γD^{*+}\to D^+\gamma, and Ds∗→DsγD_s^*\to D_s\gamma are discussed. Particular attention is paid to SU(3)SU(3) violating contributions of order mq1/2m_q^{1/2}. Experimental data on these radiative decays provide constraints on the D∗DπD^* D\pi coupling.Comment: 9 pages plus 3 pages of figures in POSTSCRIPT file appended to TeX file (uses harvmac.tex and tables.tex), UCSD/PTH 92-31, CALT-68-1816, EFI-92-45, CERN-TH.6650/9
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