Measurement of exclusive photoproduction from protons in Pb collisions at

The exclusive photoproduction of $$ meson states from protons, $$ (with $$ ), is studied in ultraperipheral $$ Pb collisions at a centre-of-mass energy per nucleon pair of $$ . The measurement is performed using the $$ decay mode, with data collected by the CMS experiment corresponding to an integrated luminosity of 32.6 $$ . Differential cross sections as functions of the $$ transverse momentum squared $$ , and rapidity y, are presented. The $$ photoproduction cross section is extracted in the rapidity range $$ , which corresponds to photon-proton centre-of-mass energies in the range $$ . The data are compared to theoretical predictions based on perturbative quantum chromodynamics and to previous measurements.