Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark
  Pair Production   We present a new measurement of the inclusive forward-backward t-tbar
production asymmetry and its rapidity and mass dependence. The measurements are
performed with 5.3 fb^{-1} of p-pbar collisions at \sqrt{s} = 1.96 TeV,
recorded with CDF II at the Fermilab Tevatron. Significant inclusive
asymmetries are observed in the laboratory and t-tbar rest frame, and are
consistent with CP conservation under interchange of t and tbar. In the t-tbar
rest frame, the asymmetry increases with the t-tbar rapidity difference,
\Delta(y), and with the invariant mass M_{t-tbar} of the t-tbar system.
Parton-level asymmetries are derived in two regions of each variable, and the
asymmetry is found to be most significant at large \Delta(y) and M_{t-tbar}.
For M_{t-tbar} > 450 GeV/c^2, the parton-level asymmetry in the t-tbar rest
frame is A^{t-tbar} = 0.475\pm 0.114 compared to a next-to-leading order QCD
prediction of 0.088\pm 0.013.

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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: econ