Ξ_c → Ξ form factors from lattice QCD with domain-wall quarks: A new piece in the puzzle of Ξ_c⁰ decay rates

2025/04/09 by Farrell, Callum, Meinel, Stefan
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2504.07302

Abstract

We present a lattice-QCD determination of the vector and axial-vector form factors that describe the charm-baryon semileptonic decays Ξ_c→ Ξℓ⁺ ν_ℓ. The calculation uses a domain-wall action for the up, down, and strange quarks, and an anisotropic clover action for the charm quark. We use four ensembles of gauge-field configurations generated by the RBC and UKQCD collaborations, with lattice spacings between 0.111 and 0.073 fm and pion masses ranging from 420 to 230 MeV. We present Standard-Model predictions for the decay rates and branching fractions of Ξ_c⁰→ Ξ_c^-ℓ⁺ ν_ℓ and Ξ_c⁺→Ξ_c⁰ℓ⁺ ν_ℓ for ℓ=e,μ. In particular, we obtain Γ(Ξ_c⁰ → Ξ^- e⁺ ν_e)/|V_cs|² = 0.2515(73) ps^-1 and B(Ξ_c⁰ → Ξ^- e⁺ ν_e) = 3.58(12) %. These values are higher than those predicted by a previous lattice calculation and substantially higher than the experimentally measured values, but consistent with expectations from approximate SU(3) flavor symmetry.

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