Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $K\pi$ $I=1/2$ $S$-wave from $\eta_c$ decay data at BaBar and classic
  Meson-Meson scattering from LASS   A recent analysis of data on the two photon production of the $\eta_c$ and
its decay to $K(K\pi)$ has determined the $K\pi$ $S$-wave amplitude in a
"model-independent" way assuming primarily that the additional kaon is a
spectator in this decay. The purpose of this paper is to fit these results,
together with classic $K\pi$ production data from LASS, within a formalism that
implements unitarity for the di-meson interaction. This fixes the $I=1/2$
$K\pi\to K\pi$ $S$-wave amplitude up to 2.4 GeV. This resolves the Barrelet
ambiguity in the original LASS analysis, and constrains the amount of
inelasticity in $K\pi$ scattering, highlighting that this becomes significant
beyond 1.8 GeV. This result needs to be checked by experimental information on
the many inelastic channels, in particular $K\eta^\prime$ and $K\pi\pi\pi$. Our
analysis provides a single representation for the $K\pi$ $S$-wave from
threshold, controlled by Chiral Perturbation Theory, through the broad
$\kappa$, $K_0^*(1430)$ and $K_0^*(1950)$ resonances. There is no arbitrary sum
of Breit-Wigner forms and random backgrounds for real $K\pi$ masses. Rather the
form provides a representation that can be translated to other processes with
$K\pi$ interactions with their own coupling functions, while automatically
maintaining consistency with the chiral dynamics near threshold, with the LASS
data and the new results on $\eta_c$ decay.

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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: stat
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
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The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph