Effect of bulk viscosity on interferometry correlations in ultrarelativistic heavy-ion collisions

A temperature-dependent bulk viscosity coefficient is used in 3 + 1-dimensional hydrodynamic simulations. I study the effect of the increase of bulk viscosity around the critical temperature on the system dynamics in central Pb + Pb collisions at root s(NN) = 2760 GeV. With increasing bulk viscosity the lifetime of the system increases slightly. Also the shape of the freeze-out hypersurface changes; the outer layers of the fireball live longer. This effect causes a small reduction of the ratio of two interferometry radii, R-out/R-side, improving the agreement with experimental data.