Scaling relation between pA and AA collisions

We compare the flowlike correlations in high multiplicity proton-nucleus (p+A) and nucleus-nucleus (A+A) collisions. At fixed multiplicity, the correlations in these two colliding systems are strikingly similar, although the system size is smaller in p+A. Based on an independent cluster model and a simple conformal scaling argument, where the ratio of the mean free path to the system size stays constant at fixed multiplicity, we argue that flow in p+A emerges as a collective response to the fluctuations in the position of clusters, just like in A+A collisions. With several physically motivated and parameter free rescalings of the recent LHC data, we show that this simple model captures the essential physics of elliptic and triangular flow in p+A collisions. We also explore the implications of the model for jet energy loss in p+A, and predict slightly larger transverse momentum broadening in p+A than in A+A at the same multiplicity.