Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Three-Nucleon Force and the $\Delta$-Mechanism for Pion Production and
  Pion Absorption   The description of the three-nucleon system in terms of nucleon and $\Delta$
degrees of freedom is extended to allow for explicit pion production
(absorption) from single dynamic $\Delta$ de-excitation (excitation) processes.
This mechanism yields an energy dependent effective three-body hamiltonean. The
Faddeev equations for the trinucleon bound state are solved with a force model
that has already been tested in the two-nucleon system above pion-production
threshold. The binding energy and other bound state properties are calculated.
The contribution to the effective three-nucleon force arising from the pionic
degrees of freedom is evaluated. The validity of previous coupled-channel
calculations with explicit but stable $\Delta$ isobar components in the
wavefunction is studied.

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The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
1
The categories of this paper are: cs
2
The categories of this paper are: math
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph