Quark structure of f0(980) from the radiative decays phi(1020)->gamma f0(980), gamma eta, gamma eta', gamma pi0 and f0(980)->gamma gamma

Anisovich, A. V.; Anisovich, V. V.; Nikonov, V. A.

Quark structure of f0(980) from the radiative decays phi(1020)->gamma f0(980), gamma eta, gamma eta', gamma pi0 and f0(980)->gamma gamma

Authors

Anisovich, A. V.

Anisovich, V. V.

Nikonov, V. A.

Description

Partial widths of the radiative decays $ϕ(1020)\toγf_0(980)$, $γη$, $γη'$, $γπ^0$ and $f_0(980)\toγγ$ are calculated assuming all mesons under consideration to be $q\bar q$ states: $ϕ(1020)$ is dominantly an $s\bar s$ state ($n\bar n$ component $\lesssim 1%$), $η$, $η'$ and $π^0$ are standard $q\bar q$ states, $η= n\bar n\cosθ- s\bar s\sinθ$ and $η'=n\bar n\sinθ+ s\bar s\cosθ$ with $θ\simeq 37^\circ$, and $f_0(980)$ is the $q\bar q$ meson with the flavour wave function $n\bar n\cosϕ+ s\bar s \sinϕ$. Calculated partial widths for the decays $ϕ\toγη$, $γη'$, $γπ^0$ are in a reasonable agreement with experiment. The measured value of the branching ratio $BR(ϕ\toγf_0(980))$ requires $25^\circ\le |ϕ|\le 90^\circ$; for the decay $f_0(980)\toγγ$ the agreement with data is reached at either $77^\circ\leϕ\le 93^\circ$ or $(-54^\circ)\leϕ\le (-38^\circ)$. Simultaneous analysis of the decays $ϕ(1020)\toγf_0(980)$ and $f_0(980)\toγγ$ provides arguments in favour of the solution with negative mixing angle $ϕ=-48^\circ\pm 6^\circ$.
some typos corrected, Fig 4. presented in more suitable form, some references are changed