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arXiv · 2607.18581

Transport phenomena and observables associated with viscous properties of an anisotropic hot QCD medium at finite baryon asymmetry

Shubhalaxmi Rath·Nicolás A. Neill
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Abstract

We have studied the transport phenomena and observables associated with viscous properties of a baryon asymmetric hot QCD medium in the presence of a weak-momentum anisotropy arising due to the asymptotic expansion of the matter in the initial stages of ultrarelativistic heavy-ion collisions. This study facilitates the understanding of the sound attenuation in the medium through the Prandtl number, the nature of flow through the Reynolds number, fluid behavior through the specific shear viscosity, and conformal symmetry through the specific bulk viscosity for an anisotropic hot QCD medium at finite baryon asymmetry. We have determined the shear and bulk viscosities by solving the relativistic Boltzmann transport equation in the relaxation time approximation method. The interactions among partons are incorporated through their distribution functions within the quasiparticle model of hot QCD medium at finite temperature, anisotropy and baryon asymmetry. We have observed a decrease in the shear and bulk viscosities in the presence of expansion-induced anisotropy for baryonless scenario as well as for baryon asymmetric scenario. Conversely, these viscosities are larger in baryon asymmetric matter compared to their counterparts in baryonless matter. The impact of anisotropy on baryon asymmetric matter is observed to be as conspicuous as on baryonless matter. The above results are broadly attributed to the squeezing of the distribution function due to the momentum anisotropy generated by the asymptotic expansion of baryon asymmetric matter and the dispersion relations of partons in the presence of anisotropy. Additionally, the aforesaid observables are also significantly modulated by the expansion-induced anisotropy in the baryon asymmetric medium, indicating new predictions for the sound attenuation, flow characteristics, fluid behavior and conformal symmetry of the said medium.

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Shubhalaxmi Rath, Nicolás A. Neill. 2026-07-20. Transport phenomena and observables associated with viscous properties of an anisotropic hot QCD medium at finite baryon asymmetry. https://arxiv.org/abs/2607.18581

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