Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instantaneous Interactions in Standard Model   Instantaneous interactions in Standard Model are derived by the resolution of
the Gauss constraints in inertial reference frames defined as irreducible
representations of the Poincare group. The relativistic covariant and
gauge-invariant S-matrix is constructed with taking into account instantaneous
interactions. Physical effects formed by the instantaneous interactions are
discussed, including the enhancement in the kaon --> pion transition
probability and the nonleptonic and semileptonic kaon decays. The low-energy
relations between these decay probability amplitudes and meson form factors are
established. Exploiting these relations we estimate possible parameters of the
differential K \to \pi e^+ e^- decay rate in the NA48/2 CERN experiment.

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The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
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The categories of this paper are: eess
3
The categories of this paper are: physics
2
The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
16
The categories of this paper are: stat