Radiative $\Xi_{b}^{-}\rightarrow \Xi^{-}\gamma$ decay

TL;DR

This paper predicts the branching ratios of radiative $ ext{Xi}_b$ baryon decays using light-cone QCD sum rules, providing results consistent with recent experimental limits and flavor symmetry predictions.

Contribution

The study applies light-cone QCD sum rules in full theory to calculate form factors and predict branching ratios for $ ext{Xi}_b$ radiative decays, extending previous theoretical approaches.

Findings

Predicted ${ m BR}( ext{Xi}_b^- o ext{Xi}^- \gamma)$ is $1.08^{+0.63}_{-0.49} imes 10^{-5}$.

Predictions are below the experimental upper limit and align with flavor symmetry expectations.

Results can be tested in future experiments and compared with other phenomenological models.

Abstract

Recently, the LHCb Collaboration performed first search for the rare radiative $\Xi_{b}^{-}\rightarrow \Xi^{-}\gamma$ decay and put an upper limit, ${\cal B}(\Xi_{b}^{-}\to \Xi^{-}\gamma) < 1.3 \times 10^{-4}$, on its branching ratio. The measurement agrees well with existing theory prediction using SU(3) flavor symmetry method, but shows a slight tension with the previous prediction from light-cone sum rules. Inspired by this, we investigate this decay as well as other radiative decays of $\Xi_b^{0(-)}(\Xi^{'-}_{b})$ to $\Xi^{0(-)}$ and $\Sigma^{0(-)}$ baryons using the form factors calculated from light-cone QCD sum rules in full theory. we obtain $ {\cal B}(\Xi_{b}^{-}\to \Xi^{-}\gamma)=1.08^{+0.63}_{-0.49} \times 10^{-5} $, which lies below the upper limit set by LHCb and is consistent with flavor-symmetry driven prediction. Our predictions on other channels may be checked in experiment and by other phenomenological approaches.