0000000000631531
AUTHOR
C. A. Dominguez
Light quark condensates from QCD sum rules
The light quark condensates have been determined by two different methods: By Laplace transformed QCD sum rules together with an improved hadronic continuum from extended PCAC and by analytic continuation by duality (ACD) of the asymptotic QCD amplitude. Both methods yield compatible results. The PCAC corrections are considerably large: for theu, d quarks near 8% and for theu, s quarks of order 60%.
Corrections to the ${\bf SU(3)\times SU(3)}$ Gell-Mann-Oakes-Renner relation and chiral couplings $L^r_8$ and $H^r_2$
Next to leading order corrections to the $SU(3) \times SU(3)$ Gell-Mann-Oakes-Renner relation (GMOR) are obtained using weighted QCD Finite Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two types of integration kernels in the FESR are used to suppress the contribution of the kaon radial excitations to the hadronic spectral function, one with local and the other with global constraints. The result for the pseudoscalar current correlator at zero momentum is $\psi_5(0) = (2.8 \pm 0.3) \times 10^{-3} GeV^{4}$, leading to the chiral corrections to GMOR: $\delta_K = (55 \pm 5)%$. The resulting uncertainties are mostly due to variations in the upper limit of integration in…