科研之友
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摘要
The fourth harmonic of the azimuthal distribution of particles v(4) has been measured for Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC). The centrality dependence of v(4) does not agree with the prediction from hydrodynamics. In particular, the ratio v(4)/(v(2))(2), where v(2) denotes the second harmonic of the azimuthal distribution of particles, is significantly larger than predicted by hydrodynamics. We argue that this discrepancy is mostly due to elliptic flow (v(2)) fluctuations. We evaluate these fluctuations on the basis of a Monte Carlo Glauber calculation. The effect of deviations from local thermal equilibrium is also studied, but appears to be only a small correction. Combining these two effects allows us to reproduce experimental data for peripheral and midcentral collisions. However, we are unable to explain the large magnitude of v(4)/(v(2))(2) observed for the most central collisions.
- 出版日期2010-9
- 单位中国地震局
