SU(3) symmetry and its breaking effects in semileptonic heavy baryon decays

TL;DR

This paper uses SU(3) symmetry to analyze semileptonic heavy baryon decays, finds significant symmetry breaking in experimental data, and explores scenarios with large SU(3) breaking effects to reconcile theory with observations.

Contribution

It provides a detailed analysis of SU(3) symmetry breaking effects in heavy baryon semileptonic decays, highlighting the large deviations from ideal symmetry.

Findings

SU(3) symmetry is severely broken in experimental data

Large SU(3) breaking effects are necessary to explain observations

Predictions for unmeasured decay modes are provided

Abstract

We employ the flavor SU(3) symmetry to analyze semileptonic decays of anti-triplet charmed baryons ($\Lambda^{+}_{c},\Xi_{c}^{+,0}$) and find that the experimental data on ${\cal B}(\Lambda_c\to\Lambda \ell^+\nu_{\ell})$ implies $\mathcal{B}(\Xi_c^0\to\Xi^-e^+\nu_{e})=(4.10\pm0.46)\%$ and $\mathcal{B}(\Xi_c^0\to\Xi^-\mu^+\nu_{\mu})= (3.98\pm0.57)\%$. When this prediction is confronted with recent experimental results from Belle collaboration $\mathcal{B}(\Xi_c^0\to\Xi^-e^+\nu_e)=1.31(04\pm07\pm38)\%$ and $\mathcal{B}(\Xi_c^0\to\Xi^-\mu^+\nu_{\mu})=1.27(06\pm10\pm 37)\%$, it is found that the SU(3) symmetry is severely broken. We then consider the generic SU(3) breaking effects in these decays and find that the data can be accommodated in different scenarios but the breaking effects are inevitably large. In some interesting scenarios, we also explore the testable implications in these scenarios which can be tested with more data become available. Similar analyses are carried out for semileptonic anti-triplet beauty baryon to octet baryons and anti-triplet charmed baryons. The validity of SU(3) for these decays can also be examined when data become available.