Hyperfine mixing in electromagnetic decay of doubly heavy $bc$ baryons

TL;DR

This paper studies how hyperfine mixing affects the electromagnetic decay widths of ground state doubly heavy $bc$ baryons, revealing significant corrections and limitations in using decay relations for experimental analysis.

Contribution

It provides a detailed analysis of hyperfine mixing effects on electromagnetic decays of $bc$ baryons, highlighting the breakdown of heavy quark symmetry relations.

Findings

Large corrections to decay widths due to hyperfine mixing.

Electromagnetic decay relations cannot be used model-independently to extract admixtures.

Contrasts with weak decay cases where heavy quark symmetry holds.

Abstract

We investigate the role of hyperfine mixing in the electromagnetic decay of ground state doubly heavy $bc$ baryons. As in the case of a previous calculation on $b\to c$ semileptonic decays of doubly heavy baryons, we find large corrections to the electromagnetic decay widths due to this mixing. Contrary to the weak case just mentioned, we find here that one can not use electromagnetic width relations obtained in the infinite heavy quark mass limit to experimentally extract information on the admixtures in a model independent way.