Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Special relativity in decays of hybrids   A decay of a heavy hybrid is expected to produce light mesons flying out with
speeds comparable to the speed of light and phenomenological models of the
decay must respect symmetries of special relativity. We study consequences of
this requirement in a class of simple constituent models with spin. Our models
respect boost symmetry because they conform to the rules of a boost-invariant
renormalization group procedure for effective particles in light-front QCD. But
rotational symmetry of the decay amplitude is not guaranteed and the parameters
in the model wave functions must take special values in order to obtain the
symmetry. When the effective interaction Hamiltonian responsible for a hybrid
decay has the same structure as the gluon-quark-antiquark interaction term
obtained by solving the renormalization group equations for Hamiltonians in
first order perturbation theory, the non-relativistic image of a hybrid as
built from a quark and an antiquark and a heavy gluon that typically resides
between the quarks, cannot produce rotationally symmetric amplitude. However,
there exists an alternative generic picture in the model that does satisfy the
requirements of special relativity. Namely, the distance between the quark and
antiquark must be much smaller than the distance between the gluon and the pair
of quarks, as if a hybrid were similar to a gluonium in which one gluon is
replaced by a quark-antiquark pair.

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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: stat