Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spin physics with light and heavy neutral mesons at Protvino   PROZA-M experiment results as well the proposal of a new spin program with
the use of a polarized proton beam are presented. Significant asymmetries were
observed in inclusive $\pi^0$ production. The new program proposes to study a
wealth of single- and double-spin observables in various reactions using
longitudinally and transversely polarized proton beams at U70. The main goal is
to define gluon contribution to nucleon spin by measuring double-spin asymmetry
in charmonium production.

7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph