Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lattice QCD study of the rare kaon decay $K^+\to\pi^+\nu\bar{\nu}$ at a
  near-physical pion mass   The rare kaon decay $K^+\to\pi^+\nu\bar{\nu}$ is an ideal process in which to
search for signs of new physics and is the primary goal of the NA62 experiment
at CERN. In this paper we report on a lattice QCD calculation of the
long-distance contribution to the $K^+\to\pi^+\nu\bar{\nu}$ decay amplitude at
the near-physical pion mass $m_\pi=170$ MeV. The calculations are however,
performed on a coarse lattice and hence with a lighter charm quark mass
($m_c^{\bar{\mathrm{MS}}}(\mbox{3 GeV})=750$ MeV) than the physical one. The
main aims of this study are two-fold. Firstly we study the momentum dependence
of the amplitude and conclude that it is very mild so that a computation at
physical masses even at a single kinematic point would provide a good estimate
of the long-distance contribution to the decay rate. Secondly we compute the
contribution to the branching ratio from the two-pion intermediate state whose
energy is below the kaon mass and find that it is less than 1% after its
exponentially growing unphysical contribution has been removed and that the
corresponding non-exponential finite-volume effects are negligibly small.

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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: dg-ga