[en] The f₀(1500) meson resonance is one of several contenders to have significant mixing with the lightest glueball. This resonance is well established from several previous experiments. Here we present the first photoproduction data for the f₀(1500) via decay into the K_S⁰K_S⁰ channel using the CLAS detector. The reaction γp -> f₀p -> K_S⁰K_S⁰p, where J = 0, 2, was measured with photon energies from 2.7 to 5.1 GeV. A clear peak is seen at 1500 MeV in the background subtracted invariant mass spectra of the two kaons. This is enhanced if the measured 4-momentum transfer to the proton target is restricted to be less than 1.0 GeV2. By comparing data with simulations, it can be concluded that the peak at 1500 MeV is produced primarily at low t, which is consistent with a t-channel production mechanism.

[en] Exclusive photoproduction cross sections have been measured for the process $\mathrm{\gamma <!--\; ??\; -->}p\to <!--\; ???\; -->p{\mathrm{\pi <!--\; ??\; -->}}^0(e^{+}{e}^{-<!--\; ???\; -->}(\mathrm{\gamma <!--\; ??\; -->}))$ with the Dalitz decay final state using tagged photon energies in the range of $E_{\mathrm{\gamma <!--\; ??\; -->}}=1.275-<!--\; ???\; -->5.425$ GeV. The complete angular distribution of the final state ${\mathrm{\pi <!--\; ??\; -->}}^0$, for the entire photon energy range up to large values of t and u, has been measured for the first time. The data obtained show that the cross section $d\mathrm{\sigma <!--\; ??\; -->}/dt$, at mid to large angles, decreases with energy as $s^{-<!--\; ???\; -->6.89\pm <!--\; ??\; -->0.26}$. This is in agreement with the perturbative QCD quark counting rule prediction of $s^{-<!--\; ???\; -->7}$. Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD based Generalized Parton Distribution mechanism at highest available invariant energy s = 11 GeV². At the same time, the Regge-exchange-based models for ${\mathrm{\pi <!--\; ??\; -->}}^0$ photoproduction are more consistent with experimental data.