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Zeitschrift für Physik C
ISSN: 0170-9739 (printed version)
ISSN: 1431-5858 (electronic version)
Abstract Volume 74 Issue 3 (1997) pp 541-548
On the chiral limit in lattice gauge theories with Wilson fermions
A. Hoferichter, V.K. Mitrjushkin (*), M. Müller-Preussker
Institut für Physik, Humboldt-Universität, D-10099 Berlin, Germany
Received: 9 February 1996 / Revised version: 20 May 1996
Abstract. The chiral limit $\kappa \simeq \kappa_c(\beta) $ in lattice gauge theories with Wilson fermions and problems related to near-to-zero (`exceptional') eigenvalues of the fermionic matrix are studied. For this purpose we employ compact lattice QED in the confinement phase. A new estimator $ \tilde m_{\pi} $ for the calculation of the pseudoscalar mass $ m_{\pi} $ is proposed which does not suffer from `divergent' contributions at $\kappa \simeq \kappa_c(\beta)$. We conclude that the main contribution to the pion mass comes from larger modes, and `exceptional' eigenvalues play no physical role. The behaviour of the subtracted chiral condensate $ \langle \overline \psi \psi \rangle_{subt} $ near $ \kappa_c(\beta) $ is determined. We observe a comparatively large value of $ \langle \overline \psi \psi \rangle_{subt} \cdot Z_P^{-1} $, which could be interpreted as a possible effect of the quenched approximation.
(*) Permanent address: Joint Institute for Nuclear Research, Dubna, Russia
Work supported by the Deutsche Froschungsgemeinschaft under research grant Mu 932/1-3
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