Corrections from Low Momentum Physics to Heavy Quark Symmetry Relations for $B\to De{\bar{\nu }}_e$ and $B\to D^{\ast }e{\bar{\nu }}_e$ Decay

Abstract

Heavy quark symmetry relations for $B\to De{\bar{\nu }}_e$ and $B\to D^{\ast }e{\bar{\nu }}_e$ form factors receive corrections suppressed by powers of the charm quark mass. For small up and down quark massed the leading corrections of order $(1/m_c{)}^{n+2}n=0,1,2,...$ have a nonanalytic dependence on the light quark masses of the form $\ell n{m}_{\pi }^2$ for $n=0$ and $(1/m_{\pi }{)}^n$ for $n=1,2,...$~. These corrections arise from very low momentum physics (i.e., well below the chiral symmetry breaking scale) and are computed using chiral perturbation theory. They are typically of order a few percent.

Comments: 14 pages