Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of the $\sigma$-resonance in determining the convergence of chiral
  perturbation theory   The dimensionless parameter $\xi = M_\pi^2/(16 \pi^2 F_\pi^2)$, where $F_\pi$
is the pion decay constant and $M_\pi$ is the pion mass, is expected to control
the convergence of chiral perturbation theory applicable to QCD. Here we
demonstrate that a strongly coupled lattice gauge theory model with the same
symmetries as two-flavor QCD but with a much lighter $\sigma$-resonance is
different. Our model allows us to study efficiently the convergence of chiral
perturbation theory as a function of $\xi$. We first confirm that the leading
low energy constants appearing in the chiral Lagrangian are the same when
calculated from the $p$-regime and the $\epsilon$-regime as expected. However,
$\xi \lesssim 0.002$ is necessary before 1-loop chiral perturbation theory
predicts the data within 1%. For $\xi > 0.0035$ the data begin to deviate
dramatically from 1-loop chiral perturbation theory predictions. We argue that
this qualitative change is due to the presence of a light $\sigma$-resonance in
our model. Our findings may be useful for lattice QCD studies.

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The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org