Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $^3$H/$^3$He ratio as a probe of the nuclear symmetry energy at
  sub-saturation densities   Within the newly updated version of the Ultra-relativistic quantum molecular
dynamics (UrQMD) model in which the Skyrme potential energy-density functional
is introduced, the yield ratio between $^3$H and $^3$He clusters emitted from
central $^{40}$Ca+$^{40}$Ca, $^{96}$Zr+$^{96}$Zr, $^{96}$Ru+$^{96}$Ru, and
$^{197}$Au+$^{197}$Au collisions in the beam energy range from 0.12 to 1
GeV$/$nucleon is studied. The recent FOPI data for the $^3$H$/$$^3$He ratio are
compared with UrQMD calculations using 13 Skyrme interactions (all exhibiting
similar values of iso-scalar incompressibility but very different density
dependences of the symmetry energy). It is found that the $^3$H$/$$^3$He ratio
is sensitive to the nuclear symmetry energy at sub-saturation densities. Model
calculations with moderately soft to linear symmetry energies are in agreement
with the experimental FOPI data. This result is in line with both, the recent
constraints on the low-density symmetry energy available in the literature and
our previous results for the high-density symmetry energy obtained with the
elliptic flow of free nucleons and hydrogen isotopes as a sensitive probe.

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The categories of this paper are: atom-ph
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th