Finite width effects in φ radiative decays

Abstract

We calculate the decay rates φ → γπ 0 π 0 and γπ 0 η in very good agreement with the recent accurate experimental data. We also point out the necessity of a φγK 0K 0 contact vertex beyond the pure K + K − loop model. The decay widths φ → γf 0 (980) and φ → γa 0 (980) are also calculated taking into account the finite widths of the scalar resonances f 0 (980) and a 0 (980). The latter are shown to be essential in order to obtain meaningful results.The resulting decay rates to γf 0 (980) and γa 0 (980) are in good agreement with the experimental ones without invoking isospin breaking in the couplings of the f 0 (980) and a 0 (980) resonances to the K + K − and K 0K 0 channels, at odds with recent proposals. The derived formula for calculating these φ radiative decay widths can be also applied in their own experimental analyses in order to obtain more precise results.#1 email: oller@um.es

Scalar mesons in radiativeϕ→K0K¯0γdecay

“…Other effects such as structure [23,24] and the finite widths of scalars [24] on the radiative φ decays have also been investigated. Oller [24] showed that the inclusion of these contribution does not change the conclusions of the charged-kaon loop model. …”

Asymmetry observables ine+e−→π+π−γin theϕregion within a chiral unitar

“…The radiative decays of the φ into ππγ has been considered as one of the most suitable reactions to get information about the f 0 (980) resonance [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. In the last decade the idea that this resonance, as well as the other light scalar resonances, a 0 (980), f 0 (600) or κ(800), are dynamically generated from multiple scattering using the ordinary chiral Lagrangians [15,16,17,18] has shed new light into the problem of the nature of the scalar mesons.…”

Constraint onKK¯compositeness of thea0(980)andSekihara1, Kumano2 2015Phys. Rev. D

“…The internal structure of the scalar mesons could be also investigated by the φ radiative decays into f 0 (980) and a 0 (980), since φ → f 0 (980)γ and a 0 (980)γ are electric dipole decays and hence the widths should reflect spatial sizes of the scalar mesons [69][70][71][72][73][74][75][76]. The couplings of the scalar mesons to two photons are also sensitive to the structure of the scalar mesons and have been investigated in, e.g., Refs.…”