QCD sum rule analysis of the subleading Isgur-Wise form factorsτ1(v⋅v′)andτ2(v⋅v′)forB→D1lν¯andB→D2*lν¯

Abstract

We present a QCD sum rule calculation of the Isgur-Wise form factor ${\ensuremath{\tau}}_{1}(v\ensuremath{\cdot}{v}^{\ensuremath{'}})$ and ${\ensuremath{\tau}}_{2}(v\ensuremath{\cdot}{v}^{\ensuremath{'}})$ for the semileptonic decays $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{1}(2420)l\overline{\ensuremath{\nu}}$ and $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{2}^{*}(2460)l\overline{\ensuremath{\nu}}$ in the framework of heavy quark effective theory. These two universal functions, associated with the matching of the weak currents in QCD onto those in the effective theory, appear at the order ${1/m}_{Q}$ in the heavy quark expansion of meson weak decay form factors.