Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An $a_0$ resonance in strongly coupled $\pi \eta$, $K\overline{K}$
  scattering from lattice QCD   We present the first calculation of coupled-channel meson-meson scattering in
the isospin $=1$, $G$-parity negative sector, with channels $\pi \eta$,
$K\overline{K}$ and $\pi \eta'$, in a first-principles approach to QCD. From
the discrete spectrum of eigenstates in three volumes extracted from lattice
QCD correlation functions we determine the energy dependence of the $S$-matrix,
and find that the $S$-wave features a prominent cusp-like structure in $\pi
\eta \to \pi \eta$ close to $K\overline{K}$ threshold coupled with a rapid turn
on of amplitudes leading to the $K\overline{K}$ final-state. This behavior is
traced to an $a_0(980)$-like resonance, strongly coupled to both $\pi \eta$ and
$K\overline{K}$, which is identified with a pole in the complex energy plane,
appearing on only a single unphysical Riemann sheet. Consideration of $D$-wave
scattering suggests a narrow tensor resonance at higher energy.

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The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys