Exploiting $\nu$-dependence of projected energy correlators in HICs

Abstract

We extend the recently derived factorization formula for energy-energy correlators to study the analytic structure of general $\nu$-point projected energy correlators in heavy ion collisions. The $\nu$-point projected energy correlators (or, $\nu$-correlators) are an analytically continued family of the integer $N$-point projected energy correlators, which probe correlations between $N$ final-state particles. By tracking the largest separation ($\chi$) between the $N$ particles, in vacuum, their structure is closely related to the DGLAP splitting functions and exhibits a classical scaling behavior $\sim 1/\chi$ which is modified by resummation through the anomalous dimensions. We show that, in a thermal medium, the $\nu$-correlators display non-trivial angular scaling already at the leading order in perturbation theory. We find that for non-integer values, particularly $\nu<1$, medium-induced jet function is enhanced compared to $\nu>1$. This is particularly manifested in the ratios of $\nu$-correlators with respect to the two-point energy correlator which encode an intrinsic angular information for $\nu<1$ when compared to large $\nu$ values. Moreover, for small-$\nu$ values, the $\nu$-correlators appear to saturate at $\nu=0.01$. We further confirm our leading-order numerical computations against simulated events from JEWEL for the parton level production cross-section. Finally, we qualitatively discuss the effect of BFKL resummation for various values of $\nu$.