2021/04/16 by T. A. Trainor, Trainor, Thomas A.
Physics and Astronomy · Mathematics · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Statistical Methods and Inference
paper · pdf · doi:10.48550/arxiv.2104.08423
The ALICE collaboration at the large hadron collider (LHC) recently reported high-statistics pt spectrum data from 5 TeV and 13 TeV p-p collisions. Particle data for each energy were partitioned into event classes based on the total yields within two disjoint pseudorapidity η intervals denoted by acronyms V0M and SPD. For each energy the spectra resulting from the two selection methods were then compared to a minimum-bias INEL > 0 average over the entire event population. The nominal goal was determination of the role of jets in high-multiplicity p-p collisions and especially the jet contribution to the low-pt parts of spectra. A related motivation was response to recent claims of "collective" behavior and other nominal indicators of quark-gluon plasma (QGP) formation in small collision systems. In the present study a two-component (soft + hard) model (TCM) of hadron production in p-p collisions is applied to the ALICE spectrum data. As in previous TCM studies of a variety of A-B collision systems the jet and nonjet contributions to p-p spectra are accurately separated over the entire pt acceptance. Distinction is maintained among spectrum normalizations, jet contributions to spectra and systematic biases resulting from V0M and SPD event selection. The statistical significance of data-model differences is established. The effect of \em spherocity (azimuthal asymmetry measure nominally sensitive to jet production) on ensemble-mean pt vs event multiplicity nch is investigated and found to have little relation to jet production. The general results of the TCM analysis are as expected from a conventional QCD description of jet production in p-p collisions.