Study of isospin violating φ excitation in e+e- → ωπ0

We study the reaction e(+)e(-) -> omega pi(0) in the vicinity of the phi mass region. The isospin-violating phi excitation is accounted for by two major mechanisms. One is electromagnetic transition and the other is strong isospin violations. For the latter, we consider contributions from the intermediate hadronic meson loops and phi-rho(0) mixing as the major mechanisms via the t- and s-channel transitions, respectively. By fitting the recent KLOE data, we succeed in constraining the model parameters and extracting the phi -> omega pi(0) branching ratio. It shows that the branching ratio is sensitive to the phi excitation line shape and background contributions. Some crucial insights into the correlation between isospin violation and Okubo-Zweig-Iizuka rule evading transitions are also learned.