Operator Product Expansion for Exclusive Decays: B^+ ->Ds^+ e+e- and B^+ -> Ds^{*+} e+e-

TL;DR

This paper develops a method combining operator product and heavy quark expansions to estimate rare B meson decay rates involving D_s mesons and electron pairs, simplifying complex long-distance calculations.

Contribution

It introduces a novel approach using operator and heavy quark expansions to systematically analyze these rare decay processes.

Findings

Decay rate estimates for B+ to D_s(d)+ e+e- and D_s*(d)+ e+e- decays.

A framework relating local operators via heavy quark spin symmetry.

Simplified calculation of long-distance contributions in rare B decays.

Abstract

The decays $B^+\to D_{s,d}^+e^+e^-$ and $B^+\to D_{s,d}^{*+}e^+e^-$ proceed through a weak and an electromagnetic interaction. This is a typical ``long distance'' process, usually difficult to compute systematically. We propose that over a large fraction of phase space a combination of an operator product and heavy quark expansions effectively turns this process into one in which the weak and electromagnetic interactions occur through a local operator. Moreover, we use heavy quark spin symmetry to relate all the local operators that appear in leading order of the operator expansion to two basic ones. We use this operator expansion to estimate the decay rates for $B^+\to D_{s,d}^{(*)+}e^+e^-$.