Prospects of $|V_{us}|$ and axial vector form factors in $\Lambda\to pe^{-}{\bar\nu}_{e}$ decay at STCF

Junxian Zhou; Shun Wang; Tao Luo; Xiaorong Zhou

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arXiv · 2509.14865

Prospects of $|V_{us}|$ and axial vector form factors in $\Lambda\to pe^{-}{\bar\nu}_{e}$ decay at STCF

Junxian Zhou·Shun Wang·Tao Luo·Xiaorong Zhou

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Abstract

We report a feasibility study of the semileptonic decay $\Lambda\to pe^{-} {\bar\nu}_{e}$ 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 at 3.097 GeV, the statistical sensitivity of the branching fraction is determined to be 0.15\%. The statistical sensitivities of form factors $g_{av}$ and $g_w$ are determined to be 0.4\% and 2.15\%, respectively. Combining this result with $g_1(0)$ from Lattice QCD, we can obtain the projected sensitivity of $|V_{us}|$, to be 0.9\%, which is comparable to the precision obtained through meson decay measurements. The precise measurement to be obtained at STCF will provide a rigorous test of Standard Model.

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Junxian Zhou, Shun Wang, Tao Luo, Xiaorong Zhou. 2025-09-18. Prospects of $|V_{us}|$ and axial vector form factors in $\Lambda\to pe^{-}{\bar\nu}_{e}$ decay at STCF. https://arxiv.org/abs/2509.14865

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