Weak Radiative Decays of K Mesons
Abstract
The possibility of a unified description for several weak radiative decays of K mesons is being investigated. In particular, those processes are considered in which the decay mechanism can be related to the strong (or electromagnetic) PVV vertex, namely K^{+}>e^{+}νγ, K^{0}_{2}>π^{+}π^{}γ, and K^{+}>π^{+}γγ, in addition to the process K^{0}_{2}>γγ, which was treated before. Vector gauge fields with current mixing and octet breaking in the PVV vertex are used, as indicated from a phenomenological Lagrangian model fitting the data on strong and radiative meson decays. For the weak nonleptonic interaction we have considered two alternatives, the currentcurrent "simplest" Hamiltonian suggested recently in connection with K^{0}_{2}>γγ decay, as well as the currentcurrent octet Hamiltonian in the form introduced by Sakurai, both satisfying the ΔS=1, ΔI=12 rule. The experimental upper limit on K^{+}>e^{+}νγ imposes limits on a free parameter of the theory related to the SU(3) symmetry breaking in the PVV vertex. Within these limits we calculate the width for K^{0}_{2}>π^{+}π^{}γ, which differs considerably from the SU(3)symmetric value and is predicted to be close to the present experimental upper limit. In the calculation of K^{+}>π^{+}γγ we consider a new class of diagrams, which appear because of the use of vector gauge fields in the Lagrangian. These diagrams involving fourleg vertices are shown to give the dominant contribution to the decay. The calculated rate and spectrum differ from those of previous calculations.
 Publication:

Physical Review D
 Pub Date:
 September 1972
 DOI:
 10.1103/PhysRevD.6.1379
 Bibcode:
 1972PhRvD...6.1379M