6533b828fe1ef96bd1288f2e
RESEARCH PRODUCT
Does interferometry probe thermalization?
Clément GombeaudJean-yves OllitraultTuomas LappiTuomas Lappisubject
PhysicsNuclear and High Energy PhysicsDegree (graph theory)Nuclear TheoryElliptic flowFOS: Physical sciencesNuclear Theory (nucl-th)Knudsen flowThermalisationAmplitudeSensitivity (control systems)Knudsen numberAtomic physicsEccentricity (mathematics)Nuclear Experimentdescription
We carry out a systematic study of interferometry radii in ultrarelativistic heavy-ion collisions within a two-dimensional transport model. We compute the transverse radii R_o and R_s as a function of p_t for various values of the Knudsen number, which measures the degree of thermalization in the system. They converge to the hydrodynamical limit much more slowly (by a factor 3) than elliptic flow. This solves most of the HBT puzzle for central collisions: R_o/R_s is in the range 1.1-1.2 for realistic values of the Knudsen number, much closer to experimental data ($\simeq 1$) than the value 1.5 from hydrodynamical calculations. The p_t dependence of R_o and R_s, which is usually said to reflect collective flow, also has a very limited sensitivity to the degree of thermalization. We then study the azimuthal oscillations of R_o, R_s, and R_{os} for non central collisions. Their amplitudes depend little on the Knudsen number, and reflect the eccentricity of the overlap area between the two nuclei.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-01-30 |