Appropriate correlation exponents between final-state anisotropic flow and multiplicity

Determine the appropriate values of the exponents α and α′n that parametrize, respectively, the correlation between the mean reaction-plane elliptic flow v2 and the centrality estimator N, and between the variance of anisotropic flow fluctuations σv n 2 and N, at fixed impact parameter in experimental final-state data, as defined in Eqs. (αexp) and (α′exp), since simulation-derived values are model-dependent and their applicability to final-state flow coefficients is unknown.

Background

To assess reconstruction accuracy, the authors introduce power-law exponents α and α′n to model correlations at fixed centrality between anisotropy measures and the multiplicity-like estimator N (or initial entropy S). They extract α and α′n from initial-condition simulations, but emphasize these are model-specific.

When applying this framework to experimental observables (final-state flow coefficients Vn), the authors note that the correct values of α and α′n governing Vn–N correlations are not established, which limits direct correction and motivates a robustness paper rather than a definitive determination.