2016/05/05 by W. C. Zhang, Zhang, W. C.
Mathematics · Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Statistical Mechanics and Entropy #Statistical Methods and Bayesian Inference
paper · pdf · doi:10.48550/arxiv.1605.01541
openalex publication_date 2016/05/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In Pb-Pb collisions at √s\rm NN = 2.76 TeV, we report on a geometrical scaling in the transverse momentum (p\rm T) spectra of inclusive charged hadrons at 0-5%, 5-10%, 10-20%, 20-30%, 30-40%, 40-50%, 50-60%, 60-70% and 70-80% centralities. This geometrical scaling is exhibited when these spectra are expressed in terms of a new scaling variable, p\rm T′=p\rm T(191.5/NA)1/(3λ+6), where NA is the number of participating nucleon pairs, λ is the scaling parameter. With the method of ratios, this scaling parameter is determined to be 1.68. We then use a single Tsallis distribution to parameterize the spectra at different centralities, and find that the Tsallis temperature T is proportional to NA1/(3λ+6), which is exactly the prediction of the geometrical scaling. The geometrical scaling also predicts that the charged-particle density per participating nucleon pair ((dN\rm ch/dη)/NA) grows as a power of NA, NA2/(3λ+6), which is confirmed by the data collected by the ALICE collaboration.