Constituent quarks and systematic errors in mid-rapidity charged multiplicity $d{N}_{\mathrm{ch}}/d\eta$ distributions

Abstract

Centrality definition in A$+$A collisions at colliders such as RHIC and LHC suffers from a correlated systematic uncertainty caused by the efficiency of detecting a p$+$p collision ($50\pm 5\%$ for PHENIX at RHIC). In A$+$A collisions where centrality is measured by the number of nucleon collisions, $N_{\mathrm{coll}}$, or the number of nucleon participants, $N_{\mathrm{part}}$, or the number of constituent quark participants, $N_{\mathrm{qp}}$, the error in the efficiency of the primary interaction trigger (Beam-Beam Counters) for a p$+$p collision leads to a correlated systematic uncertainty in $N_{\mathrm{part}}$, $N_{\mathrm{coll}}$ or $N_{\mathrm{qp}}$ which reduces binomially as the A$+$A collisions become more central. If this is not correctly accounted for in projections of A$+$A to p$+$p collisions, then mistaken conclusions can result. A recent example is presented in whether the mid-rapidity charged multiplicity per constituent quark participant $(d{N}_{\mathrm{ch}}/d\eta )/N_{\mathrm{qp}}$ in Au$+$Au at RHIC was the same as the value in p$+$p collisions.

12 pages, 10 figures. arXiv admin note: text overlap with arXiv:1705.07925

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