Decay $ϕ(1020)\to γf_0(980)$: analysis in the non-relativistic quark model approach

Abstract

We demonstrate the possibility of a good description of the processes $ϕ(1020)\to γππ$ and $ϕ(1020)\to γf_0(980)$ within the framework of non-relativistic quark model assuming $f_0(980)$ to be dominantly quark--antiquark system. Different mechanisms of the radiative decay, that is, the emission of photon by the constituent quark (additive quark model) and charge-exchange current, are considered. We also discuss the status of the threshold theorem applied to the studied reactions, namely, the behaviour of the decay amplitude at $M_{ππ} \to m_ϕ$ and $m_{f_0}\to m_ϕ$. In conclusion the arguments favouring the $q\bar q$ origin of $f_0(980)$ are listed.

24 pages, some typos corrected