6533b871fe1ef96bd12d2330

RESEARCH PRODUCT

Theoretical analysis of the γγ→π0η process

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We present a theoretical study of the $\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\eta}$ process from the threshold up to 1.4 GeV in the $\ensuremath{\pi}\ensuremath{\eta}$ invariant mass. For the s-wave ${a}_{0}(980)$ resonance state we adopt a dispersive formalism using a coupled-channel Omn\`es representation, while the d-wave ${a}_{2}(1320)$ state is described as a Breit-Wigner resonance. An analytic continuation to the ${a}_{0}(980)$ pole position allows us to extract its two-photon decay width as ${\mathrm{\ensuremath{\Gamma}}}_{{a}_{0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}}=0.27(4)\text{ }\text{ }\mathrm{keV}$.