Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hard Collisions of Spinning Protons - History and Future   There will be a review of the history of polarized proton beams, and a
discussion of the unexpected and still unexplained large transverse spin
effects found in several high energy proton-proton spin experiments at the ZGS,
AGS, Fermilab and RHIC. Next there will be a discussion of possible future
experiments on the violent collisions elastic collisions of polarized protons
at the 70 GeV U-70 accelerator at IHEP-Protvino in Russia and the new high
intensity 50 GeV J-PARC at Tokai in Japan.

25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio