Study of the nature of $\iota /\eta (1440)$ in the chiral perturbation theory approach

Abstract

The nature of $\iota /\eta (1440)$ is analysed in the framework of the hypothesis that it represents a single pseudoscalar resonance. Assuming that it arises due to the mixing between the glueball and the $q\bar{q}$ nearby states ($\eta$, ${\eta }^{\prime }$, and their radial excitations) two upper estimates are obtained for the partial width $\Gamma (\iota /\eta (1440)\to K^{\ast }K)$ --- one for the case when $\iota /\eta (1440)$ is mainly a glueball and another one when it is mainly a radial excitation of the $s\bar{s}$ state. Both estimates are obtained in the chiral perturbation theory approach taking into account the available data on the vector mesons and the pseudoscalar state K(1460), which is interpreted as a radial excitation of the $K$ meson. The same partial width is independently estimated on the basis of the combined OBELIX and Crystal Barrel data on the production of $\iota /\eta (1440)$ in $p\bar{p}$ annihilation. Comparing the results we show that the glueball content of $\iota /\eta (1440)$ is suppressed while its $s\bar{s}$ radial-excitation interpretation is favoured by the data.

Comments: 18 pages, LaTeX, no figures. Minor corrections (mainly linguistic and spelling ones)