Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pion Wave Function from QCD Sum Rules with Nonlocal Condensates   We investigate a model QCD sum rule for the pion wave function
$\varphi_{\pi}(x)$ based on the non-diagonal correlator whose perturbative
spectral density vanishes and $\Phi(x,M^2)$, the theoretical side of the sum
rule, consists of condensate contributions only. We study the dependence of
$\Phi(x,M^2)$ on the Borel parameter $M^2$ and observe that $\Phi(x,M^2)$ has a
humpy form, with the humps becoming more and more pronounced when $M^2$
increases. We demonstrate that this phenomenon reflects just the oscillatory
nature of the higher states wave functions, while the lowest state wave
function $\varphi_{\pi}(x)$ extracted from our QCD sum rule analysis,has no
humps, is rather narrow and its shape is close to the asymptotic form
$\varphi_{\pi}^{as}(x) = 6x(1-x)$.

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The categories of this paper are: stat
29
The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas