Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Angular hadron correlations probing the early medium evolution   Hard processes are a well calibrated probe to study heavy-ion collisions.
However, the information to be gained from the nuclear suppression factor R_AA
is limited, hene one has to study more differential observables to do medium
tomography. The angular correlations of hadrons associated with a hard trigger
appear suitable as they show a rich pattern when going from low p_T to high
p_T. Of prime interest is the fate of away side partons with an in-medium
pathlength O(several fm). At high p_T the correlations become dominated by the
punchtrough of the away side parton with subsequent fragmentation. We discuss
what information about the medium density can be gained from the data.

14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn