Dissipative properties of the matter formed at the Large Hadron Collider energies using Color String Percolation Model

Recently, there has been a lot of interest to understand the behavior of the newly known state of matter called Quark-Gluon Plasma (QGP), which is expected to be formed in the ultra-relativistic heavy-ion collisions at the Large Hadron Collider (LHC). Properties such as shear viscosity to entropy density ratio (η/s) and bulk viscosity to entropy density ratio (ζ/s) shed light on the dissipative nature of the fluid formed in such collisions. Study of η/s and ζ/s can indicate a possible critical point where the transition from hadron gas to deconfined quark matter occurs. Also, as predicted by several effective models, the change in behavior of (ζ/s) is expected near QCD critical temperature (T_c), where conformal symmetry breaking might be significant. On the other hand, the squared speed of sound (c²_s) can define the equation of state of the system. In our work, we have studied these observables for various collision systems at the LHC energies within the Color String Percolation Model (CSPM), which is a well established theoretical model. In summary, high-multiplicity pp collisions and heavy-ion collisions showing similar values of η=s indicate a strongly coupled QGP being formed in such collisions. The matter formed in these collisions is closest to a perfect fluid. In addition, the result from CSPM agrees with that of lattice QCD results to a reasonable extent. The detailed results on other transport coeffcients and thermodynamic variables for all the collision species at the LHC has been presented