B^+ --> D^{*+}_s gamma and B^+ --> D^{*+} gamma as Probes of V_{ub}

TL;DR

This paper explores how specific B meson decays can be used to measure the CKM matrix element |V_{ub}| by applying heavy quark and flavor symmetries, providing initial estimates in a simplified theoretical limit.

Contribution

It introduces a novel application of heavy quark and flavor symmetries to estimate decay rates relevant for |V_{ub}| extraction, in a near-degenerate quark mass limit.

Findings

Provides initial estimates of decay rates using symmetry assumptions

Suggests these decays can serve as probes for |V_{ub}|

Highlights limitations of the symmetry-based approach

Abstract

The decays B^+ --> D^{*+}_s gamma and B^+ --> D^{*+} gamma can be used for an extraction of |V_{ub}|. When the b and c quarks are nearly degenerate the rate for these modes can be determined in terms of other observed rates, namely B\bar{B} mixing and D^* --> D gamma decay. To this end we introduce a novel application of heavy quark and flavor symmetries. Although somewhat unrealistic, this limit provides us with a first estimate of these rates.