Speaker
Y. Hama
(Instituto de Fisica - USP)
Description
In a recent paper [1], the hydrodynamic code NeXSPheRIO was used in conjunction with
STAR analysis methods to study two-particle correlations as function of \Delta\eta and
\Delta\phi. Both the ridge-like near-side and double-hump away-side structures were obtained.
The appearance of the ridge-like structure is related to the combined effect of high-energy
density tubes in the initial conditions and the transverse expansion of the fluid. As far as
the near-side ridge is concerned, this statement can easily be accepted, if some high-density tubes
are located close to the surface of the hot matter. As for the less trivial away-side structure,
made of double ridges placed symmetrically with respect to the high-pT trigger in the most central
collisions, it is hard to understand. A closer look at the flow produced in the neighborhood of
such a tube, showed that actually the ridge structure in our hydrodynamics, both nearside and the
away-side, is due to a peculiar flow effect of interference between the peripheral high-energy tubes and the backgound hot matter in expansion. The pT-dependence of the two-particle correlation function in \Delta\phi, produced by this mechanism, is similar to the PHENIX data [3].
We have further studied this mechanism, computing the three-particle correlation,
which may discriminate between this and the popular Mach cone mechanism [4].
References:
[1] J. Takahashi et al. arXiv:0902.4870. [2] R. Andrade, F. Grassi, Y. Hama and W.-L. Qian, communication to ISMD2009.
[3] A.Adare et al., Phys.Rev.C77 (2008)011901(R); Phys.Rev.C78 (2008) 014901.
[4] J. Casalderrey-Solana, E.V. Shurayk, D. Teaney, hep-ph/0602183;
J. Ruppert and T. Renk, Acta Phys. Polon. Supp. 1, 633 (2008).
Primary author
Y. Hama
(Instituto de Fisica - USP)
Co-authors
F. Grassi
(Instituto de Fisica - USP)
R. Andrade
(Instituto de Fisica - USP)
W. Qian
(Instituto de Fisica - USP)
