Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Variational calculation of positronium-helium-atom scattering length   We present a variational basis-set calculational scheme for elastic
scattering of positronium atom by helium atom in S wave and apply it to the
calculation of the scattering length. Highly correlated trial functions with
appropriate symmetry are used in this calculation. We report numerical result
for the scattering length in atomic unit: $(1.0\pm 0.1)a_0$. This corresponds
to a zero-energy elastic cross section of $(4.0\pm 0.8)\pi a_0^2$.

0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn