Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct observation of dijets in central Au+Au collisions at sqrt(s_NN) =
  200 GeV   The STAR Collaboration at RHIC reports measurements of azimuthal correlations
of high transverse momentum (p_T) charged hadrons in Au+Au collisions at higher
p_T than reported previously. As p_T is increased, a narrow, back-to-back peak
emerges above the decreasing background, providing a clear dijet signal for all
collision centralities studied. Using these correlations, we perform a
systematic study of dijet production and suppression in nuclear collisions,
providing new constraints on the mechanisms underlying partonic energy loss in
dense matter.

14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an