English

Recent results on the $\Lambda \rightarrow p\ell \bar{\nu}_\ell$ semileptonic decay

High Energy Physics - Lattice 2026-02-19 v1 High Energy Physics - Phenomenology

Abstract

We present a lattice-QCD determination of the Λp\Lambda \to p vector and axial-vector form factors, providing theoretical input for studies of the semileptonic decay Λpνˉ\Lambda \to p\ell\bar{\nu}_\ell. The calculation is carried out on a single gauge ensemble with physical light, strange, and charm quark masses and delivers a precise determination of the complete set of transition form factors, including second-class contributions. Using these form factors, we compute decay rates for both the electronic and muonic channels, as well as their ratio, which offers a sensitive test of lepton-flavor universality and possible non-standard scalar or tensor interactions. This decay mode provides a theoretically well-controlled avenue for extracting the CKM matrix element Vus|V_{us}| from the baryon sector. Our estimate of Vus|V_{us}| is obtained by combining our recent lattice-QCD results with recent measurements of the relevant branching fraction reported by BESIII and LHCb.

Keywords

Cite

@article{arxiv.2602.16560,
  title  = {Recent results on the $\Lambda \rightarrow p\ell \bar{\nu}_\ell$ semileptonic decay},
  author = {Simone Bacchio and Andreas Konstantinou},
  journal= {arXiv preprint arXiv:2602.16560},
  year   = {2026}
}