Azimuth Quadrupole Spectra derived from 2.76 TeV Pb-Pb PID Differential $v_2(p_t)$ Data

Thomas A. Trainor

paper

Azimuth Quadrupole Spectra derived from 2.76 TeV Pb-Pb PID Differential $v_{2} (p_{t})$ Data

arXiv:2512.12159

Abstract

$v_{2} (p_{t})$ data are intended to estimate the amplitude of an azimuth component of particle spectra interpreted as representing elliptic flow of a dense QCD medium. As defined, $v_{2} (p_{t})$ is a ratio with a single-particle spectrum appearing in its denominator. Its numerator represents a spectrum Fourier component arising from a boosted particle source. The Cooper-Frye (CF) formalism may be used to describe emission from a boosted source. CF analysis reveals that the $v_{2} (p_{t})$ numerator includes a factor $p_{t}$ in the boost frame with major consequences for data interpretation. A unique quadrupole $p_{t}$ spectrum may be isolated from $v_{2} (p_{t})$ data and compared directly with the single-particle spectrum in the $v_{2}$ denominator and with hydro theory. A monopole boost (aka radial flow) value may be estimated from $v_{2} (p_{t})$ data. Several novel results emerge via the Cooper-Frye analysis.

13 pages, 10 figures

Azimuth Quadrupole Spectra derived from 2.76 TeV Pb-Pb PID Differential v2​(pt​) Data

Abstract

Azimuth Quadrupole Spectra derived from 2.76 TeV Pb-Pb PID Differential $v_{2} (p_{t})$ Data