Flow with PMD: Past and Future

TL;DR

This paper analyzes azimuthal photon distribution measurements at CERN SPS to estimate neutral pion anisotropy, compares it with charged particle data, and discusses implications for reaction plane determination in heavy-ion collisions.

Contribution

It introduces a method to estimate neutral pion anisotropy from photon data and explores its application for reaction plane determination in the ALICE experiment.

Findings

Photon anisotropy estimates align with charged particle data.

Neutral pion decay influences event plane correlations.

Potential to measure Jpsi absorption anisotropy in ALICE.

Abstract

Measurements of azimuthal distribution of inclusive photons using the fine granularity preshower photon multiplicity detector (PMD) at CERN SPS are used to obtain anisotropy in the azimuthal distributions. These results are used to estimate the anisotropy in the neutral pion distributions. The results are compared with results of charged particle data, both for first order and second order anisotropy. Assuming the same anisotropy for charged and neutral pions, the anisotropy in photons is estimated and compared with the measured anisotropy. The effect of neutral pion decay on the correlation between the first order and the second order event plane is also discussed. Data from PMD can also be used to estimate the reaction plane for studying any anisotropy in particle emission characteristics in the ALICE experiment at the Large Hadron Collider. In particular, we show that using the event plane from the PMD, it will be possible to measure the anisotropy in Jpsi absorption (if any) in the ALICE experiment.