Cover Story (Issue 1, 2022) | First lattice QCD calculation of semileptonic decays of charmed-strange baryons Ξc

Authors: Qi-An Zhang, Jun Hua, Fei Huang, Renbo Li, Yuanyuan Li, Caidian Lü, Peng Sun, Wei Sun, Wei Wang, Yibo Yang

Abstract: While the standard model is the most successful theory to describe all the interactions and constituents of elementary particle physics, it has been constantly scrutinized for over four decades. Weak decays of charm quarks can be used to measure the coupling strength between quarks in different families and serve as an ideal probe for CP violation. As the lowest charm-strange baryons with three different flavors, Ξc baryons(composed of csu or csd) have been extensively studied in experiments. In this study, we use state-of-the-artlattice QCD techniques to generate 2+1 clover fermion ensembles with twolattice spacings, a=(0.108, 0.080 fm)=(0.108, 0.080 fm). Then, we present the first ab-initio lattice QCD calculation of the Ξc→Ξ form factors. Our theoretical results for the Ξc→Ξℓ+νℓ decay widths are consistent with and approximately two times more precise than the latest measurements by the ALICE and Belle collaborations. Based on the latest experimental measurements, we independently obtain the quark-mixing matrixelement |Vcs|,which is in good agreement with results from other theoretical approaches.

Keywords: Ξc, semileptonic decays, latticeQCD, form factors, CKM matrix elements