Evidence for hard chiral logarithms in quenched lattice QCD

Abstract

We present the first direct evidence that quenched QCD differs from full QCD in the chiral ($m_q\to 0$) limit, as predicted by chiral perturbation theory, from our quenched lattice QCD simulations at $\beta =6/g^2=6.0$. We measured the spectrum of light hadrons on $16^3\times 64$, $24^3\times 64$ and $32^3\times 64$, using staggered quarks of masses $m_q=0.01$, $m_q=0.005$ and $m_q=0.0025$. The pion masses showed clear evidence for logarithmic violations of the PCAC relation $m_{\pi }^2\propto m_q$, as predicted by quenched chiral perturbation theory. The dependence on spatial lattice volume precludes this being a finite size effect. No evidence was seen for such chiral logarithms in the behaviour of the chiral condensate $⟨\bar{\psi }\psi ⟩$.

10 pages, 4 figures, uuencoded compressed postscript file

References in corpus (2)

• Problems with the Quenched Approximation in the Chiral Limit
• Effects of spatial size, lattice doubling and source operator on the hadron spectrum with dynamical staggered quarks

Cited by in corpus (14)

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• Hadron Spectrum with Wilson fermions
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• Light Hadron Spectrum in Quenched Lattice QCD with Staggered Quarks
• The locality of the square-root method for improved staggered quarks
• The continuum limit in the quenched approximation
• Chiral limit of light hadron mass in quenched staggered QCD