Skewness of mean transverse momentum fluctuations in heavy-ion collisions

We propose the skewness of mean transverse momentum < p(t)> fluctuations as a fine probe of hydrodynamic behavior in relativistic nuclear collisions. We describe how the skewness of the < p(t)> distribution can be analyzed experimentally, and we use hydrodynamic simulations to predict its value. We predict, in particular, that < p(t)> fluctuations have positive skew, which is significantly larger than if particles were emitted independently. We elucidate the origin of this result by deriving generic formulas relating the fluctuations of < p(t)> to the fluctuations of the early-time thermodynamic quantities. We postulate that the large positive skewness of < p(t)> fluctuations is a generic prediction of hydrodynamic models.

Automated summary

The study proposes the skewness of mean transverse momentum fluctuations as a probe of hydrodynamic behavior in relativistic nuclear collisions, predicting a positive skew significantly larger than if particles were emitted independently. The large positive skewness of these fluctuations is postulated to be a generic prediction of hydrodynamic models, elucidated through generic formulas relating the fluctuations of < p(t)> to early-time thermodynamic quantities.