Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Azimuthal anisotropy in high-energy heavy-ion collisions at RHIC
  energies   Directed and elliptic event anisotropy parameters measured in the experiments
at relativistic heavy-ion collider are presented. The possible origin of the
measured elliptic anisotropy parameter $v_2$ and its sensitivity to the early
phase of the high-energy heavy-ion collisions are discussed.

1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph