2000/06/30 by S. Gardner, G. Valencia · 1 citation
Physics and Astronomy · #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.1103/physrevd.62.094024
published as Phys.Rev.D62:094024,2000 · 29 pages, 1 ps fig, refs. added, to appear in Phys. Rev. D
arxiv created 2000/07/31 · openalex publication_date 2000/10/11 · arxiv updated 2009/11/30 · openalex created_date 2020/05/21 · openalex updated_date 2026/07/28
We consider the impact of isospin violation on the analysis of \stackrel\ensuremath→K\ensuremathπ\ensuremathπ decays. We scrutinize, in particular, the phenomenological role played by the additional weak amplitude, of |\ensuremathΔI|=5/2 in character, incurred by the presence of isospin violation. We show that Watson's theorem is appropriate in O(md\ensuremath-mu), so that the inferred \ensuremathπ\ensuremathπ phase shift at √(s)=mK determines the strong phase difference between the I=0 and I=2 amplitudes in \stackrel\ensuremath→K\ensuremathπ\ensuremathπ decay. We find the magnitude of the |\ensuremathΔI|=5/2 amplitude thus implied by the empirical branching ratios to be larger than expected from estimates of isospin-violating strong and electromagnetic effects. We effect a new determination of the octet and 27-plet coupling constants with strong-interaction isospin violation and with electromagnetic effects, as computed by Cirigliano, Donoghue, and Golowich, and find that we are unable to resolve the difficulty. Exploring the role of |\ensuremathΔI|=5/2 transitions in the CP-violating observable \ensuremathε^\ensuremath'/\ensuremathε, we determine that the presence of a |\ensuremathΔI|=5/2 amplitude impacts the empirical determination of \ensuremathω, the ratio of the real parts of the |\ensuremathΔI|=3/2 to |\ensuremathΔI|=1/2 amplitudes, and that it generates a decrease in the estimation of \ensuremathε^\ensuremath'/\ensuremathε.