Hyperon Weak Radiative Decay
Résumé
We revisit the hyperon weak radiative decays in the framework of the non-relativistic constituent quark model. This study confirms the nonlocal feature of the hyperon weak radiative transition operators, which are dominated by the pole terms, and an overall self-consistent description of the available experimental data for the Cabibbo-favored hyperon weak radiative decays is presented. It provides a natural mechanism for evading the Hara theorem, where sizeable parity-violating contributions can come from the intermediate orbital excitations. Cancellations between pole terms also explain the significant SU(3) flavor symmetry breaking manifested by the experimental data. We also discuss several interesting selection rules arising from either the electromagnetic or the weak interaction vertices. These features suggest nontrivial relations among various hyperon decays.
Mots clés
hyperon: decay
hyperon: radiative decay
symmetry breaking: flavor
quark model: constituent
operator: transition
flavor: SU(3)
pole
weak interaction
nonrelativistic
electromagnetic
selection rule
excited state
nonlocal
parity: violation
effective Hamiltonian
Cabibbo angle
Sigma+ --> p photon
Lambda --> n photon
Xi0 --> Lambda photon
Xi0 --> Sigma0 photon
Sigma0 --> n photon