Update on splitting of lifetimes of $c$ and $b$ hyperons within the heavy quark expansion and decays ${\Xi }_Q\to {\Lambda }_Q\pi$

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 ${\Xi }_c\to {\Lambda }_c\pi$.

Comments: 10 pages