Diphoton elastic scattering in UPC at smaller $W_{\gamma \gamma }$

Abstract

We present a study of photon-photon scattering for $W_{\gamma \gamma }<5$ GeV. We extend earlier calculations of this cross section for $W_{\gamma \gamma }>$ 5 GeV into the low mass range where photoproduction of the pseudoscalar mesons $\eta$(548), ${\eta }^{{}^{\prime }}(958)$ and other mesonic resonances contribute to the two-photon final states. We consider the dominant background of the two photon final state which arises from $\gamma \gamma$ decays of photoproduced ${\pi }^0{\pi }^0$-pairs. We discuss how to reduce the background by imposing cuts on different kinematical variables. We present results for ALICE and LHCb kinematics.

Comments: 5 pages, 6 figures, 1 table, a talk presented at PHOTON2019, Frascati, Italy, June 3-7, 2019