Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Proton G_E/G_M from beam-target asymmetry   The ratio of the proton's electric to magnetic form factor, G_E/G_M, can be
extracted in elastic electron-proton scattering by measuring either cross
sections, beam-target asymmetry or recoil polarization. Separate determinations
of G_E/G_M by cross sections and recoil polarization observables disagree for
Q^2 > 1 (GeV/c)^2. Measurement by a third technique might uncover an unknown
systematic error in either of the previous measurements. The beam-target
asymmetry has been measured for elastic electron-proton scattering at Q^2 =
1.51 (GeV/c)^2 for target spin orientation aligned perpendicular to the beam
momentum direction. This is the largest Q^2 at which G_E/G_M has been
determined by a beam-target asymmetry experiment. The result, \muG_E/G_M =
0.884 +/- 0.027 +/- 0.029, is compared to previous world data.

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The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
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The categories of this paper are: eess
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat