Unified study of hyperon semileptonic decays in a relativistic three-quark model
Abstract
We present a unified theoretical study of semileptonic decays of ground state octet hyperons using the relativistic three-quark model (R3QM). A key innovation of our approach is that all baryon wave functions are determined by fitting the baryon mass spectrum with a semirelativistic potential model, leading to predictions for weak transition amplitudes without free parameters. Adopting these wave functions, we calculate the decay widths, branching fractions, lepton flavor universality ratios, as well as the angular correlation and spin asymmetry parameters for the octet channels. The calculated values agree with the available experimental data and give predictions for channels with limited experimental information. We further compute the complete set of octet transition form factors without any additional free parameters, so that the weak current can be examined beyond the rate observables. In the well measured Λ→ p ℓ-ν̅ℓ channel, the calculated leading vector and axial-vector form factors, f1(0) and g1(0), agree well with recent lattice QCD results, and the g1/f1 ratio is consistent with recent BESIII measurements. Beyond the leading vector and axial-vector terms, the complete form factor set separates the weak magnetism, second class, and the pole contribution associated with the partially conserved axial current (PCAC) relation. The weak magnetism term f2 shows the clearest channel dependence compared with lattice QCD results, and its smaller values in some channels may point to transverse current strength not fully saturated by pure qqq valence components. This work provides a framework for connecting octet hyperon weak form factors to the spin--flavor and spatial structure of baryons at the quark level, and gives testable weak current observables for future hyperon semileptonic decay measurements.
Related
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BibTeX
@misc{ni2026unified,
title = {{Unified study of hyperon semileptonic decays in a relativistic three-quark model}},
author = {Ru-Hui Ni and Zhen-Yang Wang and Jia-Jun Wu and Bing-Song Zou},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.26596},
eprint = {2606.26596},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.26596},
}
RIS
TY - UNPB
TI - Unified study of hyperon semileptonic decays in a relativistic three-quark model
AU - Ru-Hui Ni
AU - Zhen-Yang Wang
AU - Jia-Jun Wu
AU - Bing-Song Zou
PY - 2026
DA - 2026/09/08
PB - arXiv
DO - 10.48550/arxiv.2606.26596
UR - https://arxiv.org/abs/2606.26596
AB - We present a unified theoretical study of semileptonic decays of ground state octet hyperons using the relativistic three-quark model (R3QM). A key innovation of our approach is that all baryon wave functions are determined by fitting the baryon mass spectrum with a semirelativistic potential model, leading to predictions for weak transition amplitudes without free parameters. Adopting these wave functions, we calculate the decay widths, branching fractions, lepton flavor universality ratios, as well as the angular correlation and spin asymmetry parameters for the octet channels. The calculated values agree with the available experimental data and give predictions for channels with limited experimental information. We further compute the complete set of octet transition form factors without any additional free parameters, so that the weak current can be examined beyond the rate observables. In the well measured Λ→ p ℓ^-ν̅_ℓ channel, the calculated leading vector and axial-vector form factors, f_1(0) and g_1(0), agree well with recent lattice QCD results, and the g_1/f_1 ratio is consistent with recent BESIII measurements. Beyond the leading vector and axial-vector terms, the complete form factor set separates the weak magnetism, second class, and the pole contribution associated with the partially conserved axial current (PCAC) relation. The weak magnetism term f_2 shows the clearest channel dependence compared with lattice QCD results, and its smaller values in some channels may point to transverse current strength not fully saturated by pure qqq valence components. This work provides a framework for connecting octet hyperon weak form factors to the spin--flavor and spatial structure of baryons at the quark level, and gives testable weak current observables for future hyperon semileptonic decay measurements.
ER -