
Gosta Gustafson, Leif Lonnblad, Andras Ster, Tamas Csorgo
Total, inelastic and (quasi)elastic cross sections of high energy pA and gammaA reactions with the dipole formalism
Abstract
In order to understand the initial partonic state in protonnucleus and electronnucleus collisions, we investigate the total, inelastic, and (quasi)elastic cross sections in pA and gammaA collisions, as these observables are insensitive to possible collective effects in the final state interactions. We used as a tool the DIPSY dipole model, which is based on BFKL dynamics including nonleading effects, saturation, and colour interference, which we have extended to describe collisions of protons and virtual photons with nuclei. We present results for collisions with O, Cu, and Pb nuclei, and reproduce preliminary data on the pPb inelastic cross section at LHC by CMS and LHCb. The large NN cross section results in pA scattering that scales approximately with the area. The results are compared with conventional Glauber model calculations, and we note that the more subtle dynamical effects are more easily studied in the ratios between the total, inelastic and (quasi)elastic cross sections. The smaller photon interaction makes the gammaA collisions more closely proportional to A, and we see here that future electronion colliders would be valuable complements to the pA collisions in studies of dynamical effects from correlations, coherence and fluctuations in the initial state in high energy nuclear collisions.
LU TP 1524
