Bulk viscosity effects on the collective flow harmonics in heavy-ion collisions are investigated, on an event-by-event basis, using a newly developed 2+1 Lagrangian hydrodynamic code named v-usphydro, which implements the smoothed particle hydrodynamics algorithm for viscous hydrodynamics. A new formula for the bulk viscous corrections present in the distribution function at freeze-out is derived, starting from the Boltzmann equation for multi-hadron species. Bulk viscosity is shown to enhance the collective flow Fourier coefficients from v2(pT) to v5(pT) when pT∼1-2.5 GeV, even when the bulk viscosity to entropy density ratio, ζ/s, is significantly smaller than 1/(4π).
ASJC Scopus subject areas
- Nuclear and High Energy Physics