Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-particle angular correlations in p+p and Cu+Cu collisions at PHOBOS   We present results on two-particle angular correlations in p+p and Cu+Cu
collisions over a broad range of ($\eta$,$\phi$). The PHOBOS detector has a
uniquely large angular coverage for inclusive charged particles. This allows
for the study of correlations on both long and short range pseudorapidity
scales. A complex two-dimensional correlation structure emerges which is
interpreted in the context of a cluster model. The cluster size and its decay
width are extracted from the two-particle pseudorapidity correlation function.
Relative to p+p collisions, Cu+Cu reactions show a non-trivial decrease of
cluster size with increasing centrality. These results may provide insight into
the hadronization stage of the hot and dense medium created in heavy ion
collisions.

24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ