Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Momentum dependence of the imaginary part of the $\omega$- and
  $\eta^\prime$-nucleus optical potential   The photoproduction of $\omega$ and $\eta^\prime$ mesons off carbon and
niobium nuclei has been measured as a function of the meson momentum for
incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The
mesons have been identified via the $\omega \rightarrow \pi^0 \gamma
\rightarrow 3 \gamma$ and $\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6
\gamma$ decays, respectively, registered with the CBELSA/TAPS detector system.
From the measured meson momentum distributions the momentum dependence of the
transparency ratio has been determined for both mesons. Within a Glauber
analysis the in-medium $\omega$ and $\eta^\prime$ widths and the corresponding
absorption cross sections have been deduced as a function of the meson
momentum. The results are compared to recent theoretical predictions for the
in-medium $\omega$ width and $\eta^\prime$-N absorption cross sections. The
energy dependence of the imaginary part of the $\omega$- and
$\eta^\prime$-nucleus optical potential has been extracted. The finer binning
of the present data compared to the existing data allows a more reliable
extrapolation towards the production threshold. The modulus of the imaginary
part of the $\eta^\prime$ nucleus potential is found to be about three times
smaller than recently determined values of the real part of the
$\eta^\prime$-nucleus potential, which makes the $\eta^\prime$ meson a suitable
candidate for the search for meson-nucleus bound states. For the $\omega$
meson, the modulus of the imaginary part near threshold is comparable to the
modulus of the real part of the potential. As a consequence, only broad
structures can be expected which makes the observation of $\omega$ mesic states
very difficult experimentally.

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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: supr-con
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: nlin