Jean-Francois Paquet

Importance of the Bulk Viscosity of QCD in Ultrarelativistic Heavy-Ion Collisions

We investigate the consequences of a nonzero bulk viscosity coefficient on the transverse momentum spectra, azimuthal momentum anisotropy, and multiplicity of charged hadrons produced in heavy ion collisions at LHC energies. The agreement between a realistic 3D hybrid simulation and the experimentally measured data considerably improves with the addition of a bulk viscosity coefficient for strongly interacting matter. This paves the way for an eventual quantitative determination of several QCD transport coefficients from the experimental heavy ion and hadron-nucleus collision programs.

Anisotropic flow of thermal photons as a quark-gluon plasma viscometer

We present state-of-the-art calculations of viscous photon emission from nuclear collisions at RHIC and LHC. Fluctuating initial density profiles are evolved with event-by-event viscous hydrodynamics. Momentum spectra of thermal photons radiated by these explosively expanding fireballs and their

Viscous photons in relativistic heavy ion collisions

p_T

Collectivity and electromagnetic radiation in small systems

-differential anisotropic flow coefficients

Photon Emission from a Momentum Anisotropic Quark-Gluon Plasma

v_n(p_T)

Extracting the bulk viscosity of the quark–gluon plasma

are computed, both with and without accounting for viscous corrections to the standard thermal emission rates. Viscous corrections to the rates are found to have a larger effect on the

Event-by-event direct photon anisotropic flow in relativistic heavy-ion collisions

v_n

Probing the early-time dynamics of relativistic heavy-ion collisions with electromagnetic radiation

coefficients than the viscous suppression of hydrodynamic flow anisotropies. The benefits of taking the ratio of elliptic to triangular flow,

Photons at the RHIC: the role of viscosity and of initial state fluctuations

v_2/v_3

Effects of bulk viscosity and hadronic rescattering in heavy ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

, are discussed, and the spacetime regions which contribute dominantly to the photon flow harmonics are identified. The directed flow