Constituent quarks and systematic errors in mid-rapidity charged multiplicity ($dN_{\rm ch}/d\eta$ distributions
ORAL
Abstract
Although it was demonstrated more than 13 years ago that the increase in midrapidity $dN_{\rm ch}/d\eta$ with increasing centrality of Au+Au collisions at RHIC was linearly proportional to the number of constituent quark participants (or ``wounded quarks'', $Q_W$) in the collision, it was only in the last few years that generating the spatial positions of the three quarks in a nucleon according to the Fourier transform of the measured electric charge form factor of the proton could be used to connect $dN_{\rm ch}/d\eta/Q_W$ as a function of centrality in p(d)$+$A and A$+$A collisions with the same value of $dN_{\rm ch}/d\eta/Q_W$ determined in p$+$p collisions. One calculation, which only compared its calculated $dN_{\rm ch}/d\eta/Q_W$ in p$+$p at $\sqrt{s_{NN}}=200$ GeV to the least central of 12 centrality bin measurements in Au$+$Au by PHENIX, claimed that the p$+$p value was higher by ``about 30\%'' from the band of measurements vs. centrality. However the clearly quoted systematic errors were ignored for which a 1 standard deviation systematic shift would move all the 12 Au$+$Au data points to within 1.3 standard deviations of the p$+$p value, or if the statistical and systematic errors are added in quadrature a difference of 35 $\pm$ 21\% .
–
Authors
-
Michael Tannenbaum
Physics Department, Brookhaven National Laboratory, Upton, NY 11973-5000