Remarks on sum rules in the heavy quark limit of QCD - Université Clermont Auvergne Accéder directement au contenu
Communication Dans Un Congrès Année : 2001

Remarks on sum rules in the heavy quark limit of QCD

Résumé

We underline a problem existing in the heavy quark limit of QCD concerning the rates of semileptonic B decays into P-wave $D_J(j)$ mesons, where $j = {1 \\over 2}$ (wide states) or $j = {3 \\over 2}$ (narrow states). The leading order sum rules of Bjorken and Uraltsev suggest $\\Gamma [ \\bar{B} \\to D_{0,1} ({1 \\over 2}) \\ell \\nu ] \\ll \\Gamma [ \\bar{B} \\to D_{1,2} ({3 \\over 2}) \\ell \\nu ]$, in contradiction with experiment. The same trend follows also from a sum rule for the subleading $1/m_Q$ curent matrix element correction $\\xi_3(1)$. The problem is made explicit in relativistic quarks models \à la Bakamjian and Thomas, that give a transparent physical interpretation of the latter as due, not to a $L \\cdot S$ force, but to the Wigner rotation of the light quark spin. We point out moreover that the selection rule for decay constants of $j = {3 \\over 2}$ states, $f_{3/2} = 0$, predicts, assuming the model of factorization, the opposite hierarchy $\\Gamma [ \\bar{B} \\to \\bar{D}_{s_{1,2}} ({3 \\over 2}) D^{(*)} ] \\ll \\Gamma [ \\bar{B} \\to \\bar{D}_{s_{0,1}} ({1 \\over 2}) D^{(*)} ]$.

Dates et versions

hal-00008580 , version 1 (09-09-2005)

Identifiants

Citer

A. Le Yaouanc, L. Oliver, O. Pene, J. -C. Raynal, Vincent Morenas. Remarks on sum rules in the heavy quark limit of QCD. International Europhysics Conference on HEP, Jul 2001, Budapest, Hungary. ⟨hal-00008580⟩
31 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More