Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of Spin Correlation Parameters A$_{NN}$, A$_{SS}$, and
  A_${SL}$ at 2.1 GeV in Proton-Proton Elastic Scattering   At the Cooler Synchrotron COSY/J\"ulich spin correlation parameters in
elastic proton-proton (pp) scattering have been measured with a 2.11 GeV
polarized proton beam and a polarized hydrogen atomic beam target. We report
results for A$_{NN}$, A$_{SS}$, and A_${SL}$ for c.m. scattering angles between
30$^o$ and 90$^o$. Our data on A$_{SS}$ -- the first measurement of this
observable above 800 MeV -- clearly disagrees with predictions of available of
pp scattering phase shift solutions while A$_{NN}$ and A_${SL}$ are reproduced
reasonably well. We show that in the direct reconstruction of the scattering
amplitudes from the body of available pp elastic scattering data at 2.1 GeV the
number of possible solutions is considerably reduced.

26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con