F. J. Ynduráin*

Experimental status of the ππ isoscalar S wave at low energy : f 0 ( 600 ) pole and scattering length

Precision Determination of the Muon g μ − 2 and ᾱ Q . E . D . ( M 2 Z ) ∗

We present a summary of the results of two recent precise calculations of the muon anomalous magnetic moment and the electromagnetic coupling on the Z.

Consistency checks of pion-pion scattering data and chiral dispersive calculations

We have evaluated forward dispersion relations for scattering amplitudes that follow from direct fits to several sets of ππ scattering experiments, together with the precise K decay results, and high to energy data. We find that some of the most commonly used experimental sets, as well as some recent theoretical analyses based on Roy equations, do not satisfy these constraints by several standa...

Bound states of heavy quarks in QCD

Bound states of heavy ¯ qq quarks are reviewed within the context of QCD, paying attention to what can be derived from the theory with a reasonable degree of rigour. This is compared with the results of semiclassical arguments. Among new results, we report a very precise O(α 4 s) evaluation of b, c quark masses from quarkonium spectrum with a potential to two loops.

Restriction on SUSY Masses from Z → hadrons

We remark that the precision of recent determinations of αs(M 2 Z) is such that one can get bounds on supersymmetric partner masses (squark and gluino) by requiring consistency of determinations of αs at " low " energies, where those particles do not contribute, and on the Z peak. For approximately degenerate squarks and gluinos with mass m, we find the bound m ≥ 173 GeV, at the 2σ level. At th...