Calculation of centrality bias factors in $p$+A collisions based on a positive correlation of hard process yields with underlying event activity

Understand

Hard scattering yields in centrality-selected proton-- and deuteron--nucleus ($p$+A) collisions are generally compared to nucleon--nucleon ($NN$) cross-sections scaled to the appropriate partonic luminosity using geometric models derived from an analysis of minimum bias $p$+A interactions.

• In general, these models assume that hard process rates and the magnitude of the soft event activity in the underlying $NN$ collisions is uncorrelated.
• When included, these correlations influence the measured yield in a nominal centrality interval, an effect typically referred to as a "centrality bias".
• In this work, the impact of a positive correlation between the hard scattering yield and the underlying event activity in individual $NN$ collisions is investigated.