Speaker
Description
Heavy quarks are usually modeled as Brownian probes of the quark-gluon plasma, with momentum exchange encoded by drag and Gaussian diffusion. Recent weak- and strong-coupling results show that this diffusion truncation misses a robust feature of real-time heavy-quark dynamics: the longitudinal momentum-transfer distribution has a Gaussian core but asymmetric exponential tails. These tails are fixed by the analytic structure of the heavy-quark momentum-transfer kernel and encode rare, large kicks absent from a Gaussian description. Crucially, once the exponential tails are included, equilibration is controlled by a generalized kernel-level condition rather than by the ordinary Gaussian Einstein relation between drag and diffusion.
I will discuss the non-Gaussian structure found in arXiv:2604.21895 and present its first implementation in heavy-ion phenomenology, obtained by modifying the heavy-quark extension of the Hybrid Model of jet quenching introduced in arXiv:2510.24847. This provides a concrete way to test how exponential tails affect equilibration, heavy-flavor observables, and the extraction of transport coefficients such as the heavy-quark diffusion coefficient.