We suggest a theoretical framework for the description of double photon and proton-antiproton photoproduction off the proton $\gamma +p\to 2\gamma +p$ and $\gamma +p\to \overline{p}p+p$, which takes into account the contribution of the scalar mesons $f_0(1370)$, $f_0(1500)$, and $f_0(1710)$. These scalars are considered as mixed states of a glueball, nonstrange and strange quarkonia. Our framework is based on the use of effective hadronic Lagrangians that phenomenologically take into account two-gluon exchange effects governing the $\gamma +p\to 2\gamma +p$ and $\gamma +p\to \overline{p}p+p$ processes. Present results can be used to guide the possible search for these reactions by the GlueX Collaboration at JLab.

• Received 4 May 2016

DOI:https://doi.org/10.1103/PhysRevD.94.034010