$p_T$-Dependent Particle Number Fluctuations From Principal Component Analyses in Hydrodynamic Simulations of Heavy-Ion Collisions

Understand

We carry out a principal component analysis of fluctuations in a hydrodynamic simulation of heavy-ion collisions, and compare with experimental data from the CMS collaboration.

• The leading and subleading principal components of elliptic and triangular flow reproduce the trends seen in data.
• By contrast, the principal components of multiplicity fluctuations show an interesting difference in their $p_T$ dependence for simulations compared to experimental data.
• Specifically, the leading component increases with $p_T$ in hydrodynamics, while it is constant in experiment.