Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: PHENIX results on direct photon-hadron correlations   Direct photon-hadron correlations are a golden channel to study parton
in-medium energy loss in QGP. The modification of the effective fragmentation
function for the away-side jet can be measured by comparing integrated
away-side yields of direct photon-hadron pairs in heavy ion collisions to those
in p+p. We measured per-trigger-yield of associated hadrons in Au+Au collisions
and observed that there is a suppression compared to p+p for higher momentum
fraction ($z_T$) hadrons. This can be explained by the opacity of the hot
medium: energetic partons from the initial hard scattering lose energy while
traversing it. A yield enhancement on the other hand has been found at low
$z_T$ (high $\xi$). Medium response is likely to be responsible for the
enhanced production of these lower momentum particles. The same measurement is
done in d+Au collisions and the result suggests that no modification to the
fragmentation function is observed, given the current uncertainties.

22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
14
The categories of this paper are: math-ph