Hydrodynamic Short-Range Correlations from Boltzmann-Langevin Equation

We investigate hydrodynamic contributions to short-range two-particle correlations in relativistic heavy-ion collisions using the Boltzmann-Langevin equation. We derive and solve the transport equation for equal-time two-point correlations, obtaining both local and non-local contributions that scale with transport coefficients. The non-local correlations emerging from 2-to-2 scattering dynamics provide a hydrodynamic signature in short-range correlation measurements.

💡 Research Summary

In this work the authors address the long‑standing assumption that short‑range two‑particle correlations observed in relativistic heavy‑ion collisions are dominated solely by non‑flow effects such as jet fragmentation. By employing the Boltzmann‑Langevin equation—a kinetic description that incorporates stochastic noise consistent with the fluctuation‑dissipation theorem—they demonstrate that thermal fluctuations of the quark‑gluon plasma (QGP) fluid can be converted into measurable particle‑pair correlations at freeze‑out.

The paper begins by relating fluctuations of hydrodynamic fields (temperature, chemical potential, flow velocity) to fluctuations of the single‑particle distribution function ( \delta f ). The central observable, the equal‑time two‑point correlator
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