Scalar and Tensor Form Factors for $Λ\rightarrow p\ell \barν_\ell$ from Lattice QCD

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Hauptverfasser: Alexandrou, Constantia, Bacchio, Simone, Konstantinou, Andreas, Vakana, Eleni
Format: Preprint
Veröffentlicht: 2026
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author Alexandrou, Constantia
Bacchio, Simone
Konstantinou, Andreas
Vakana, Eleni
author_facet Alexandrou, Constantia
Bacchio, Simone
Konstantinou, Andreas
Vakana, Eleni
contents We present a determination of the scalar and tensor $Λ\to p$ transition form factors using lattice QCD. These form factors are relevant for semileptonic hyperon decays in the presence of extensions of the Standard Model that include scalar and tensor interactions. The calculation is carried out using a gauge ensemble of twisted mass fermions at the physical pion mass, following the same strategy as our recent study on vector and axial form factors for the same transition. We provide the complete set of form factors as functions of $q^2$ employing a model-independent parametrization. We examine their impact on searches for non-standard charged-current interactions via the muon-to-electron decay-rate ratio $R^{μe}=Γ(Λ\to pμ\barν_μ)/Γ(Λ\to pe\barν_e)$, where scalar and tensor contributions enter linearly and are helicity-enhanced relative to the electron channel. We compare this first-principles prediction for the decay-rate ratio with recent experimental measurements, thereby enabling improved constraints on non-standard charged-current interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16025
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scalar and Tensor Form Factors for $Λ\rightarrow p\ell \barν_\ell$ from Lattice QCD
Alexandrou, Constantia
Bacchio, Simone
Konstantinou, Andreas
Vakana, Eleni
High Energy Physics - Lattice
We present a determination of the scalar and tensor $Λ\to p$ transition form factors using lattice QCD. These form factors are relevant for semileptonic hyperon decays in the presence of extensions of the Standard Model that include scalar and tensor interactions. The calculation is carried out using a gauge ensemble of twisted mass fermions at the physical pion mass, following the same strategy as our recent study on vector and axial form factors for the same transition. We provide the complete set of form factors as functions of $q^2$ employing a model-independent parametrization. We examine their impact on searches for non-standard charged-current interactions via the muon-to-electron decay-rate ratio $R^{μe}=Γ(Λ\to pμ\barν_μ)/Γ(Λ\to pe\barν_e)$, where scalar and tensor contributions enter linearly and are helicity-enhanced relative to the electron channel. We compare this first-principles prediction for the decay-rate ratio with recent experimental measurements, thereby enabling improved constraints on non-standard charged-current interactions.
title Scalar and Tensor Form Factors for $Λ\rightarrow p\ell \barν_\ell$ from Lattice QCD
topic High Energy Physics - Lattice
url https://arxiv.org/abs/2604.16025