Influence of Non-extensivity on the drag and diffusion coefficients of hadronic matter

In this work, we investigate the drag and diffusion coefficients of various hadrons propagating through a hadronic thermal bath by employing the Fokker Planck equation within the framework of Tsallis nonextensive statistics. The nonextensive parameter $q$ accounts for the deviation from equilibrium and provides a more realistic description of the medium that is not perfectly thermalized. The hadronic bath, consisting of various mesonic and baryonic species, is characterized by different mass cutoffs that control the spectral composition of the medium. Our analysis shows that both the drag $F$ and momentum diffusion coefficients $Γ$ increases exponentially with temperature and increases systematically with increasing $q$ and mass cutoff. The spatial diffusion coefficient $D_x$ exhibits a decreasing trend with temperature $T$, $q$ and mass cutoff which highlights the significant influence of nonequilibrium effects and hadronic composition on the transport behaviour of hadrons, offering valuable insights into the thermal and dynamical properties of the hadronic phase preceding freezeout in heavy ion collisions. Additionally, we have studied the relaxation time of heavy mesons such as $D_0$, $J/ψ$ and $Υ$. We found that the heavier mesons relaxed later in comparison to the lighter mesons in the hadronic medium.

💡 Research Summary

The paper investigates how non‑equilibrium effects, encoded in the Tsallis non‑extensive parameter q, influence the drag (F), momentum diffusion (Γ), and spatial diffusion (Dₓ) coefficients of hadrons propagating through a hot hadronic medium. Using the Fokker‑Planck equation in the small‑momentum‑transfer limit, the authors express the drag and diffusion coefficients as moments of the transition rate w(P,K). They adopt a constant elastic cross‑section σ and integrate over the thermal bath using the Tsallis distribution f₀(p)=