Short Distance Analysis of $\bar B -> D^{(*)0} e+e-$ and $\bar B -> J/psi e+e-$

Abstract

Over a large fraction of phase space a combination of an operator product and heavy quark expansions effectively turn the decay $\bar B -> D^{(*)0} e+e-$ into a ``short distance'' process, i.e., one in which the weak and electromagnetic interactions occur through single local operators. These processes have an underlying W-exchange quark diagram topology and are therefore Cabibbo allowed but suppressed by combinatoric factors and short distance QCD corrections. Our technique allows a clearer exploration of these effects. For the decay $\bar B_{d,s} -> J/psi(η_c) e+e-$ one must use a non-relativistic (NRQCD) expansion, in addition to an operator product expansion and a heavy quark effective theory expansion. We estimate the decay rates for $\bar B_{d,s} -> J/psi e+e-$, $\bar B_{d,s} -> eta_c e+e-$, $\bar B_{d,s} -> D^{*0} e+e-$ and $\bar B_{d,s} -> D^{0} e+e-$.