Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei
  and the Nolen-Schiffer Anomaly   The neutron-proton mass difference in (isospin asymmetric) nuclear matter and
finite nuclei is studied in the framework of a medium-modified Skyrme model.
The proposed effective Lagrangian incorporates both the medium influence of the
surrounding nuclear environment on the single nucleon properties and an
explicit isospin-breaking effect in the mesonic sector. Energy-dependent
charged and neutral pion optical potentials in the s- and p-wave channels are
included as well. The present approach predicts that the neutron-proton mass
difference is mainly dictated by its strong part and that it markedly decreases
in neutron matter. Furthermore, the possible interplay between the effective
nucleon mass in finite nuclei and the Nolen-Schiffer anomaly is discussed. In
particular, we find that a correct description of the properties of mirror
nuclei leads to a stringent restriction of possible modifications of the
nucleon's effective mass in nuclei.

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The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: stat
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: nlin