3 research outputs found
The Electromagnetic Mass Differences of Pions and Kaons
We use the Cottingham method to calculate the pion and kaon electromagnetic
mass differences with as few model dependent inputs as possible. The
constraints of chiral symmetry at low energy, QCD at high energy and
experimental data in between are used in the dispersion relation. We find
excellent agreement with experiment for the pion mass difference. The kaon mass
difference exhibits a strong violation of the lowest order prediction of
Dashen's theorem, in qualitative agreement with several other recent
calculations.Comment: 40 pages, Latex, needs axodraw. and psfig. macros, 4 figure
Hyperon Nonleptonic Weak Decays Revisited
We first review the current algebra - PCAC approach to nonleptonic octet
baryon 14 weak decay B (\to) (B^{\prime})(\pi) amplitudes. The needed four
parameters are independently determined by (\Omega \to \Xi \pi),(\Lambda K) and
(\Xi ^{-}\to \Sigma ^{-}\gamma) weak decays in dispersion theory tree order. We
also summarize the recent chiral perturbation theory (ChPT) version of the
eight independent B (\to) (B^{\prime}\pi) weak (\Delta I) = 1/2 amplitudes
containing considerably more than eight low-energy weak constants in one-loop
order.Comment: 10 pages, RevTe