Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dissipation in the very early stage of the hydrodynamic evolution in
  relativistic heavy ion collisions   We propose a modification of the hydrodynamic model of the dynamics in
ultrarelativistic nuclear collisions. A modification of the energy-momentum
tensor at the initial stage describes the lack of isotropization of the
pressure. Subsequently, the pressure is relaxing towards the equilibrium
isotropic form in the local comoving frame. Within the Bjorken scaling solution
a bound is found on the decay time of the initial anisotropy of the
energy-momentum tensor. For the strongest dissipative effect allowed, we find a
relative entropy increase of about 30%, a significant hardening of the
transverse momentum spectra, and no effect on the HBT radii.

19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc