Spin-isospin correlated configurations in complex nuclei and neutron skin effect in W-+/- production in high-energy proton-lead collisions

摘要

We extend our Monte Carlo algorithm for generating global configurations in nuclei to include different spatial distributions of protons and neutrons in heavy nuclei, taking into account the difference of spatial correlations between two protons, two neutrons, and proton-neutron pairs. We generate configurations for Ca-48 and Pb-208 neutron-rich nuclei, which can be used in general-purpose high-energy A(e, e' p), p-A, and A-A event generators. As an application of lead configurations, we developed an algorithm for proton-heavy nucleus collisions at the CERN Large Hadron Collider for final states with a hard interaction in the channels where cross sections for p-p and p-n scattering differ. Soft interactions are taken into account in the color fluctuation extension of the Glauber algorithm, taking into account the inherently different transverse geometry of soft and hard p-N collisions. We use the new event generator to test an interesting observation of Paukkunen [Phys. Lett. B 745, 73 (2015)] that the ratio of W-+/- production rates in p-Pb collisions should significantly deviate from the inclusive value for peripheral collisions due to the presence of a neutron skin. We qualitatively confirm expectation of Paukkunen, although, for a realistic centrality trigger, we find the effect to be a factor of 2 smaller than the original estimate.