Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: QCD in the delta-Regime   The delta-regime of QCD is characterised by light quarks in a small spatial
box, but a large extent in (Euclidean) time. In this setting a specific variant
of chiral perturbation theory - the delta-expansion - applies, based on a
quantum mechanical treatment of the quasi one-dimensional system. In
particular, for vanishing quark masses one obtains a residual pion mass M_pi^R,
which has been computed to the third order in the delta-expansion. A comparison
with numerical measurements of this residual mass allows for a new
determination of some Low Energy Constants, which appear in the chiral
Lagrangian. We first review the attempts to simulate 2-flavour QCD directly in
the delta-regime. This is very tedious, but results compatible with the
predictions for M_pi^R have been obtained. Then we show that an extrapolation
of pion masses measured in a larger volume towards the delta-regime leads to
good agreement with the theoretical predictions. From those results, we also
extract a value for the (controversial) sub-leading Low Energy Constant \bar
l_3.

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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: ao-sci