Study of the ρ0 Decay into π0π0γ Within Framework of Chiral Perturbation Theory with Resonances

In this work, we calculate the branching ratio (BR) of the decay process ρ0→π0π0γ within the theoretical framework of chiral perturbation theory with resonances, employing the odd intrinsic parity lagrangian. Our analysis shows that the BR depends solely on the LECs c57≡c5+c7, and d4. Since the experimentally measured BR does not provide sufficient constraints, the number of free parameters is reduced by applying on-shell and off-shell conditions at the interaction vertices. Our result shows that using full on-shell conditions is not consistent with the experimental BR. Therefore, we present an allowed region (contour plot) for (c57,d4) that is compatible with the experimental BR. We emphasize that once the differential BR becomes accessible, a fitting procedure can be carried out to delineate the parameter space.