0000000000622658
AUTHOR
Gerhard Ecker
showing 5 related works from this author
Isospin breaking in K ->pi pi decays
2003
28 páginas, 3 figuras, 4 tablas.-- arXiv:hep-ph/0310351v2
K 0 --> pi 0 gammagamma decays in chiral perturbation theory
1987
The decays K L,S --> pi 0gammagamma are calculated within the framework of chiral perturbation theory. The amplitude for K L --> pi 0gammagamma is found to be finite at the one-loop level yielding a branching ratio of 6.8 × 10 -7. The decay spectra of both decays are very characteristic and provide good tests of the effective chiral symmetry realization of the standard model.
pi(0)-pi mixing and CP violation
2000
We discuss pi(0)-eta mixing and its implication for epsilon'/epsilon to next-to-leading order in the low-energy expansion. The big effect due to eta-eta' mixing is shown to be largely cancelled by other contributions occurring at the same order in the chiral expansion.
Green function in the resonance region
2004
11 páginas, 2 figuras.-- arXiv:hep-ph/0404004v2
Unitarity and K$_{L}$ --> $\pi^{0}\gamma\gamma$
1993
We discuss the rare decay K(L) --> pi0gammagamma. Although the recently measured 2gamma-invariant-mass distribution is in quite good agreement with the lowest-order chiral perturbation theory prediction, there seems to be a discrepancy with the calculated branching ratio. We extend the previous computations to next-to-leading order, O(p6). The two dominant mechanisms at this order are emphasized: the two-pion intermediate state and vector meson exchange.