Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Four-nucleon system with $\Delta$-isobar excitation   The four-nucleon bound state and scattering below three-body breakup
threshold are described based on the realistic coupled-channel potential CD
Bonn + $\Delta$ which allows the excitation of a single nucleon to a $\Delta$
isobar. The Coulomb repulsion between protons is included. In the four-nucleon
system the two-baryon coupled-channel potential yields effective two-, three-
and four-nucleon forces, mediated by the $\Delta$ isobar and consistent with
each other and with the underlying two-nucleon force. The effect of the
four-nucleon force on the studied observables is much smaller than the effect
of the three-nucleon force. The inclusion of the $\Delta$ isobar is unable to
resolve the existing discrepancies with the experimental data.

36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an