Eur. Phys. J. C (2025) 85: 1408
https://doi.org/10.1140/epjc/s10052-025-15131-8

Regular Article - Experimental Physics

Prospects of $|V_{\mathit{us}}|$ and axial vector form factors in $\Lambda \to p{e}^{-}{\overline{\nu }}_e$ decay at STCF

¹ Fudan University, 200443, Shanghai, People’s Republic of China
² Key Laboratory of Nuclear Physics on Ion-Beam Application (MOE), Institute of Modern Physics, Fudan University, 200443, Shanghai, People’s Republic of China
³ School of Mathematics and Physics, Southwest University of Science and Technology, 621010, Mianyang, China
⁴ University of Science and Technology of China, 230026, Hefei, People’s Republic of China
⁵ State Key Laboratory of Particle Detection and Electronics, 230026, Hefei, People’s Republic of China

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Received: 18 September 2025
Accepted: 28 November 2025
Published online: 11 December 2025

Abstract

We report a feasibility study of the hyperon semileptonic decay $\Lambda \to p{e}^{-}{\overline{\nu }}_e$ by using a fast simulation software package at STCF. With an anticipated integrated luminosity of 3.4 trillion $J/\psi$ per year at a center-of-mass energy of 3.097 GeV, the statistical sensitivity of the branching fraction is determined to be 0.15%. The statistical sensitivities of form factors $g_{\mathit{av}}$ and $g_w$ are determined to be 0.4% and 2.15%, respectively. The projected sensitivity of $|V_{\mathit{us}}|$ is obtained by combining this result with $g_1(0)$ from Lattice QCD, to be 0.9%, including the systematic uncertainty from the LQCD input and the statistical uncertainties of input branching fraction and form factors. The precise measurement to be obtained at STCF will provide a rigorous test of the Standard Model.