From the γγ → p(p)over-bar reaction to the production of p(p)over-bar pairs in ultraperipheral ultrarelativistic heavy-ion collisions at the LHC

In this paper we consider the production of proton-antiproton pairs in two-photon interactions in electron-positron and heavy-ion collisions. We try to understand the dependence of the total cross section on the photon-photon c.m. energy as well as corresponding angular distributions measured by the Belle Collaboration for the gamma gamma -> p (p) over bar process. To understand the Belle data we include the proton-exchange, the f(2)(1270) and f(2)(1950) s-channel exchanges, as well as the hand-bag mechanism. The helicity amplitudes for the gamma gamma -> f(2) -> p (p) over bar process are written explicitly based on a Lagrangian approach. The parameters of vertex form factors are adjusted to the Belle data. Having described the angular distributions for the gamma gamma -> p (p) over bar process we present first predictions for the ultraperipheral, ultrarelativistic, heavy-ion reaction (PbPb)-Pb-208-Pb-208 -> (PbPb)-Pb-208-Pb-208 p (p) over bar Both, the total cross section and several differential distributions for experimental cuts corresponding to the ALICE, ATLAS, CMS, and LHCb experiments are presented. We find the total cross section 100 mu b for the ALICE cuts, 160 mu b for the ATLAS cuts, 500 mu b for the CMS cuts, and 104 mu b taking into account the LHCb cuts. This opens a possibility to study the gamma gamma -> p (p) over bar process at the LHC.