The bulk viscosity (ζ) of the hadronic medium has been estimated within the ambit of the Hadron √ s N N ) and find that the bulk viscosity to entropy density ratio, ζ/s is larger at FAIR than LHC energies.

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Recent studies reveal that at high energies, collisions of small system like p + p give signatures similar to that widely observed in heavy ion collisions hinting towards a possibility of forming a medium with collective behaviour. With this motivation, in this work, we have used Glauber model, which is traditionally applied to heavy ion collisions, in small system using anisotropic and inhomogeneous density profile of proton and found that the proposed model reproduces the charged particle multiplicity distribution of p + p collisions at LHC energies very well. Collision geometric properties like mean impact parameter, mean number of binary collisions ( N coll ) and mean number of participants ( Npart ) at different multiplicities are determined. Having estimated N coll , we have calculated nuclear modification-like factor (Rpp) in p+p collisions. We also estimated eccentricity and elliptic flow as a function of charged particle multiplicity using linear response to initial geometry.

The effects of the non-extensive statistics on the nonlinear propagation of perturbations have been studied within the scope of relativistic second order dissipative hydrodynamics with non-extensive equation of state. We have shown that the equations, describing the propagation of nonlinear waves under such situation admit solutions similar to that of KdV-type (Korteweg–De Vries) equations. Apart from their preserved solitonic behaviour the dissipative nature of these waves are also observed. The waves with larger amplitude and width dissipate less and propagate faster and these waves deplete more for both smaller values of Tsallis parameter (q) and temperature (T) of the medium. For vanishingly small transport coefficients the nonlinear waves show breaking nature. These findings suggest that the nature of the propagation of the nonlinear waves may serve as a good probe to differentiate between the extensive and non-extensive thermodynamic nature of a fluid, such as the quark-gluon plasma, produced in relativistic nuclear collisions.

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