Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-pion Bose-Einstein correlations in central Pb-Pb collisions at
  $\sqrt{s_{\rm NN}}$ = 2.76 TeV   The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb
collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is
presented. We observe a growing trend with energy now not only for the
longitudinal and the outward but also for the sideward pion source radius. The
pion homogeneity volume and the decoupling time are significantly larger than
those measured at RHIC.

20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc