Subleading form factors at order 1/m_Q in terms of leading quantities using the non-forward amplitude in HQET

Abstract

We consider the non-forward amplitude within the Heavy Quark Effective theory. We show that one can obtain new information on the subleading corrections in 1/m_Q. We illustrate the method by deriving new simple relations between the functions Xsi_3(w) and Lambdabar Xsi(w) and the sums Sum_n DeltaE^(n)_j tau^(n)_j(1) tau^(n)_j(w) (j=1/2,3/2), that involve leading quantities, namely the Isgur-Wise functions tau^(n)_j(w) and the level spacings DeltaE^(n)_j. The simplicity of our results follows from the fact that, for the non-forward amplitude B(v_i)->D^(n)(v')->B(v_f), there are three variables (w_i,w_f,w_if)=(v_i.v',v_f.v',v_i.v_f) independent in a certain domain, and we consider the zero recoil frontier (w,1,w) where only a finite number of j^P states contribute (1/2^+,3/2^+). These sum rules reduce to known results at w=1, for Lambdabar obtainted by Voloshin, and for Xsi_3(1) obtained by Le Yaouanc et al. and by Uraltsev, and generalizes them to all values of w. We discuss phenomenological applications of these results, in particular the check of Bakamjian-Thomas quark models and the comparison with the QCD Sum Rules approach.

36 pages

References in corpus (6)

• Study of B- => D**0 pi-(D**0 => D(*)+ pi-) decays
• A "BPS expansion" for B and D mesons
• Lower bounds on the curvature of the Isgur-Wise function
• Bounds on the derivatives of the Isgur-Wise function from sum rules in the heavy quark limit of QCD
• Sum rules in the heavy quark limit of QCD
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Cited by in corpus (5)

• The decays $\bar{B}\to D^{\ast \ast }\pi$ and the Isgur-Wise functions ${\tau }_{1/2}(w)$, ${\tau }_{3/2}(w)$
• Explicit form of the Isgur-Wise function in the BPS limit
• Lagrangian perturbations at order 1/m${}_{\mathbf{Q}}$ and the non-forward amplitude in Heavy Quark Effective Theory
• Theoretical Interest in B-Meson Physics at the B factories, Tevatron and the LHC
• On the form factors of semileptonic baryon decays in Heavy Quark Effective Theory