Mixing angle of doubly heavy baryons in QCD

TL;DR

This paper calculates the mixing angles of doubly heavy baryons using QCD sum rules, revealing large angles slightly smaller than non-relativistic quark model predictions.

Contribution

It provides the first QCD sum rules-based estimates of mixing angles for doubly heavy baryons, offering a comparison with non-relativistic quark model results.

Findings

Mixing angles are approximately 16° and 18° for Xi_bc and Omega_bc baryons.

QCD sum rules predict slightly smaller mixing angles than the non-relativistic quark model.

Large mixing angles suggest significant state mixing in doubly heavy baryons.

Abstract

We calculate the mixing angles between the spin--1/2, $\Xi_{bc}$--$\Xi^\prime_{bc}$ and $\Omega_{bc}$--$\Omega^\prime_{bc}$ states of doubly heavy baryons within the QCD sum rules method. It is found that the mixing angles are large and have the values $\varphi_{\Xi_{bc}} = 16^0 \pm 5^0$ and $\varphi_{\Omega_{bc}} = 18^0 \pm 6^0$, respectively. The mixing angles are slightly smaller compared to the predictions of the non--relativistic quark model, $\varphi_{\Xi_{bc}} = 25.5^0$ and $\varphi_{\Omega_{bc}} = 25.9^0$.