Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tetraquark operators in lattice QCD and exotic flavour states in the
  charm sector   We present a general class of operators resembling compact tetraquarks which
have a range of colour-flavour-spin structures, transform irreducibly under the
symmetries of the lattice and respect other relevant symmetries. These
constructions are demonstrated in lattice QCD calculations with light quarks
corresponding to $m_\pi =$ 391 MeV. Using the distillation framework,
correlation functions involving large bases of meson-meson and tetraquark
operators are computed in the isospin-1 hidden-charm and doubly-charmed
sectors, and finite-volume spectra are extracted with the variational method.
We find the spectra are insensitive to the addition of tetraquark operators to
the bases of meson-meson operators. For the first time, through using diverse
bases of meson-meson operators, the multiple energy levels associated with
meson-meson levels which would be degenerate in the non-interacting limit are
extracted reliably. The number of energy levels in each spectrum is found to be
equal to the number of expected non-interacting meson-meson levels in the
energy region considered and the majority of energies lie close to the
non-interacting levels. Therefore, there is no strong indication for any bound
state or narrow resonance in the channels we study.

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The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
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The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph