Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: UrQMD calculations of two-pion HBT correlations in central Pb-Pb
  collisions at $\sqrt{s_{NN}}=2.76$ TeV   Two-pion Hanbury-Brown-Twiss (HBT) correlations for central Pb-Pb collisions
at the Large-Hadron-Collider (LHC) energy of $\sqrt{s_{NN}}=2.76$ TeV are
investigated for the first time with the microscopic transport model UrQMD
(Ultra-relativistic Quantum Molecular Dynamics). The transverse momentum
dependence of the Pratt-Bertsch HBT radii is extracted from a three dimensional
Gaussian fit to the correlator in the longitudinal co-moving system (LCMS).
Qualitative agreement with the ALICE data is obtained, however $R_{out}$ is
overpredicted by nearly 50%. The LHC results are also compared to data from the
STAR experiment at RHIC. For both energies we find that the calculated
$R_O/R_S$ ratio is always larger than data, indicating that the emission in the
model is less explosive than observed in the data.

11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn