Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-temperature antihydrogen-atom scattering   A simple method to include the strong force in atom-antiatom scattering is
presented. It is based on the strong-force scatteringn length between the
nucleon and antinucleon. Using this method elastic and annihilation cross
sections are calculated for hydrogen-antihydrogen and helium-antihydrogen
scattering. The results are compared to first-order perturbation theory using a
pseudo potential. The pseudo-potential approach works fairly well for
hydrogen-antihydrogen scattering, but fails for helium-antihydrogen scattering
where strong-force effects are more prominent.

15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th