Associative photoproduction of Roper resonance and meson

İngilizce (OpenAlex)

Associative photoproduction of $\ensuremath{\omega}$ meson and ${N}^{*}(1440)$ on nucleons, $\ensuremath{\gamma}+\stackrel{\ensuremath{\rightarrow}}{N}\ensuremath{\omega}{+N}^{*}(1440),$ in the near threshold region is investigated in a framework employing effective Lagrangians. Besides $\ensuremath{\pi}$ exchange in the t channel, baryon exchanges, i.e., N and ${N}^{*}$ exchanges, in the s and u channels are also taken into account in calculations of differential cross section and beam asymmetry. Important inputs of this model are the vector and tensor coupling constants of $\ensuremath{\omega}{\mathrm{NN}}^{*}(1440)$ vertex, which are assumed to be equal to the values of these couplings for $\ensuremath{\omega}\mathrm{NN}$ vertex. Using our previous estimation of $\ensuremath{\omega}\mathrm{NN}$ coupling constants obtained from a fit to available experimental data on photoproduction of $\ensuremath{\omega}$ meson in the near threshold region, we produce the necessary numerical predictions for different observables in $\ensuremath{\gamma}+\stackrel{\ensuremath{\rightarrow}}{N}\ensuremath{\omega}{+N}^{*}(1440).$ Numerical results show that at low $|t|$ dominant contribution comes from t channel $\ensuremath{\pi}$ exchange while the effects of nucleon and ${N}^{*}(1440)$ pole terms can be seen at large $|t|.$ Our predictions for the differential cross section and beam asymmetry for the processes $\ensuremath{\gamma}+\stackrel{\ensuremath{\rightarrow}}{N}\ensuremath{\omega}{+N}^{*}(1440),$ where N is proton and neutron, at ${E}_{\ensuremath{\gamma}}=2.5\mathrm{GeV}$ are presented with zero width approximation and also with the inclusion of width effects of ${N}^{*}(1440).$