Update on splitting of lifetimes of $c$ and $b$ hyperons within the heavy quark expansion and decays $\Xi_Q \to \Lambda_Q \pi$

TL;DR

This paper discusses how recent LHCb measurements of hyperon lifetimes align with heavy quark expansion theory, enabling precise determination of matrix elements and predicting decay rates for certain charmed hyperons.

Contribution

It demonstrates that recent experimental data supports heavy quark expansion predictions and allows for accurate extraction of matrix elements and decay rate bounds.

Findings

LHCb lifetime measurements agree with heavy quark expansion.

Matrix elements of four-quark operators are precisely determined.

Predicted lower bound for $ ext{decay rate of }\Xi_c o ext{Lambda}_c ext{ pi}$.

Abstract

It is argued that the results of recent precision measurements by LHCb of the lifetimes of charmed and bottom hyperons are very well consistent with the description within heavy quark expansion and allow to accurately determine matrix elements of light-flavor nonsinglet four-quark operators over the hyperons and to accurately reproduce the difference of lifemes of $\Lambda_b$ and $\Xi_b^-$. When combined with the recent LHCb results on the decay $\Xi_b^- \to \Lambda_b \pi^-$ this leads to prediction of a lower bound on the rate of the decays $\Xi_c \to \Lambda_c \pi$.