Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Top quark spin correlations at hadron colliders: Predictions at
  next-to-leading order QCD   The collider experiments at the Tevatron and the LHC will allow for detailed
investigations of the properties of the top quark. This requires precise
predictions of the hadronic production of $t\bar t$ pairs and of their
subsequent decays. In this Letter we present for the reactions $p {\bar p}, p p
\to t{\bar t} + X \to \ell^+\ell'^-X$ the first calculation of the dilepton
angular distribution at next-to-leading order (NLO) in the QCD coupling,
keeping the full dependence on the spins of the intermediate $t\bar{t}$ state.
The angular distribution reflects the degree of correlation of the $t$ and
$\bar t$ spins which we determine for different choices of $t$ and $\bar t$
spin bases. In the case of the Tevatron, the QCD corrections are sizeable, and
the distribution is quite sensitive to the parton content of the proton.

23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th