Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin effects in heavy quarkonia   A model based on a nonrelativistic potential supplemented by spin dependent
terms of the Breit-Fermi type is described. This model reproduces the known
masses of the $\bar{b}b$ quarkonia within 1MeV and the known masses of the
$\bar{c}c$ quarkonia within 5MeV. Many predictions are made, some of them, e.g.
for the fine splittings of the high $L$ states of the $\bar{b}b$ quarkonia and
of the mass spectrum of the $\bar{b}c$ quarkonia, significantly different from
previous predictions made by other authors.

11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio