UrQMD CALCULATIONS OF HBT CORRELATIONS IN CENTRAL HEAVY-ION COLLISIONS AT LHC

Two-pion Hanbury-Brown-Twiss (HBT) correlations for central Pb-Pb collisions at the Large-Hadron-Collider (LHC) energy of root s(NN) = 2.76 TeV are investigated with the cascade mode of the microscopic transport model UrQMD (Ultra-relativistic Quantum Molecular Dynamics). The transverse momentum dependence of the 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.