Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Matter scattering in $R_{\mu \nu}^2$ gravity and unitarity   We investigate the ultraviolet (UV) behavior of two-scalar elastic scattering
with graviton exchanges in higher curvature gravity theory. In the Einstein
gravity, matter scattering is shown not to satisfy tree unitarity at high
energy. Among a few possible directions to cure unitarity (i.e. UV completion
of Einstein gravity), string theory, modified gravity, inclusion of
high-mass/high-spin states, we take $R_{\mu\nu}^2$ gravity coupled to matter.
We show that the matter scattering with graviton interactions satisfies the
unitarity bound at high energy, in contrast with the Einstein gravity. The
difference in unitarity property of the two gravity theories is due to that in
the UV behavior of the propagator and is probably connected to that in another
UV property, namely renormalizability property of the two.

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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci