Chiral limit of QCD

Abstract

This talk contains an analysis of quenched chiral perturbation theory and its consequences. The chiral behavior of a number of quantities such as the pion mass $m_{\pi }^2$, the Bernard-Golterman ratios $R$ and $\chi$, the masses of nucleons, and the kaon B-parameter are examined to see if the singular terms induced by the additional Goldstone boson,${\eta }^{\prime }$, are visible in present data. The overall conclusion (different from what I presented at the lattice meeting) of this analysis is that, with some caveats on the extra terms induced by ${\eta }^{\prime }$ loops, the standard expressions break down when extrapolating the quenched data with $m_q<m_s/2$ to physical light quarks. I then show that due to the single and double poles in the quenched ${\eta }^{\prime }$, the axial charge of the proton cannot be calculated using the Adler-Bell-Jackiw anomaly condition. I conclude with a review of the status of the calculation of light quark masses from lattice QCD.

Self-contained PS file containing 11 pages. Final version of the review talk presented at LATTICE 94, Bielefeld, Germany, Sept 27-Oct1,1994. Source available from http://nqcd.lanl.gov/Lattice_QCD/papers/cpt/

Cited by in corpus (17)

• Electromagnetic Splittings and Light Quark Masses in Lattice QCD
• Quenched Chiral Perturbation Theory for Heavy-light Mesons
• Finite-volume two-pion energies and scattering in the quenched approximation
• Hadron Spectrum with Wilson fermions
• The Light Quark Masses from Lattice Gauge Theory
• Advances in the Determination of Quark Masses
• Chiral corrections to the axial charges of the octet baryons from quenched QCD
• Topological aspects of QCD
• Dynamical Wilson fermions and the problem of the chiral limit in compact lattice QED
• Finite Volume Effects and Quenched Chiral Logarithms
• Light hadron spectroscopy
• Scattering in the quenched approximation
• Light Quark Mass Determinations from the Lattice
• The continuum limit in the quenched approximation
• Mass spectrum and decay constants in the continuum limit
• Status Report on Weak Matrix Element Calculations
• Effects of Improvement: $f_{\pi }$ and $m_q$