Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Examination of the directed flow puzzle in heavy-ion collisions   Recent STAR data for the directed flow of protons, antiprotons, and charged
pions obtained within the beam energy scan program are analyzed within the
parton-hadron-string-dynamics (PHSD and HSD) transport models and a 3-fluid
hydrodynamics (3FD) approach. Both versions of the kinetic approach, HSD and
PHSD, are used to clarify the role of partonic degrees of freedom. The PHSD
results, simulating a partonic phase and its coexistence with a hadronic one,
are roughly consistent with data. The hydrodynamic results are obtained for two
equations of state (EoS), a pure hadronic EoS and an EoS with a crossover type
transition. The latter case is favored by the STAR experimental data. Special
attention is paid to the description of antiproton directed flow based on the
balance of $p\bar{p}$ annihilation and the inverse processes for $p\bar{p}$
pair creation from multimeson interactions. Generally, the semiqualitative
agreement between the measured data and the model results supports the idea of
a crossover type of quark-hadron transition that softens the nuclear EoS but
shows no indication of a first-order phase transition.

27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics