Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low Mass Dimuon Production in p-A Collisions at $\sqrt{s} = 27.5$ GeV
  with NA60   The NA60 experiment has studied low-mass muon pair production in
proton-nucleus collisions with a system of Be, Cu, In, W, Pb and U targets
using a 400 GeV/$c$ proton beam at the CERN SPS. The mass spectrum is well
described by the superposition of the two-body and Dalitz decays of the light
neutral mesons $\eta$, $\rho$, $\omega$, $\eta'$ and $\phi$. A new
high-precision measurement of the electromagnetic transition form factors of
the $\eta$ and $\omega$ mesons is presented, complemented with a measurement of
the temperature parameter of the $\rho$ meson in cold nuclear matter. The $\pt$
spectra for the $\omega$ and $\phi$ mesons are extracted in the full $\pt$
range accessible, up to $\pt = 2$ GeV/$c$. The nuclear dependence of the
production cross sections for the $\eta$, $\omega$ and $\phi$ mesons has been
investigated in terms of the power law $\sigma_\mathrm{pA} \propto
\mathrm{A}^\alpha$, and the $\alpha$ parameter was studied as a function of
$\pt$.

14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph