Wave functions fixed from a mass-spectrum fit in the relativistic three-quark model are used to compute branching fractions, LFU ratios, and the complete set of octet hyperon semileptonic transition form factors without extra parameters, agreeing with data and lattice results where available.
Helicity Amplitudes and Angular Decay Distributions
2 Pith papers cite this work. Polarity classification is still indexing.
abstract
I discuss how to obtain angular decay distributions for sequential cascade decays using helicity methods. The angular decay distributions follow from a reasonably simple master formula involving bilinear forms of helicity amplitudes and Wigner's $d$ functions. I discuss in some detail the issue of gauge invariance for off-shell gauge bosons. As a technical exercise I calculate the linear relation between the helicity amplitudes and the invariant amplitudes of semileptonic and rare baryon decays. I discuss two explicit examples of angular decay distributions for (i) the decay $t\to b+W^+(\to \ell^+\nu_\ell)$ (which leads to the notion of the helicity fractions of the $W^+$), and (ii) the sequential decay $\Lambda_b\to\Lambda(\to p\pi^-)+J/\psi(\to \ell^+\ell^-)$.
fields
hep-ph 2years
2026 2verdicts
UNVERDICTED 2representative citing papers
Light-front quark model with nonvalence contributions predicts branching ratios for Λ→p ℓ ν̄ decays of 8.32×10^{-4} (electron) and 1.31×10^{-4} (muon) consistent with BESIII.
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Unified study of hyperon semileptonic decays in a relativistic three-quark model
Wave functions fixed from a mass-spectrum fit in the relativistic three-quark model are used to compute branching fractions, LFU ratios, and the complete set of octet hyperon semileptonic transition form factors without extra parameters, agreeing with data and lattice results where available.
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Semileptonic Decays of $\Lambda \to p \ell^{-} \bar{\nu}_{\ell}$ in the Light-Front Dynamics
Light-front quark model with nonvalence contributions predicts branching ratios for Λ→p ℓ ν̄ decays of 8.32×10^{-4} (electron) and 1.31×10^{-4} (muon) consistent with BESIII.