Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Sivers asymmetry in $J/\Psi$ and lepton pair production at COMPASS   The abundant production of lepton pairs via $J/\Psi$ creation at COMPASS,
$\pi ^\pm \, p^\uparrow \to J/\Psi \, X \to \ell^+ \ell^- X$, allows a
measurement of the transverse Single Spin Asymmetry generated by the Sivers
effect. The crucial issue of the sign change of the Sivers function in lepton
pair production, with respect to Semi Inclusive Deep Inelastic Scattering
processes, can be solved. Predictions for the expected magnitude of the Single
Spin Asymmetry, which turns out to be large, are given.

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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph