0000000000699058
AUTHOR
Helmut Neufeld
Isospin breaking in K ->pi pi decays
28 páginas, 3 figuras, 4 tablas.-- arXiv:hep-ph/0310351v2
Meson resonances, large N_c and chiral symmetry
14 páginas, 2 tablas.-- arXiv:hep-ph/0305311v1
Flavor physics in the quark sector
218 páginas, 106 figuras, 89 tablas.-- arXiv:0907.5386v2.-- Report of the CKM workshop, Rome 9-13th Sep. 2008.-- et al.
Isospin Violation inϵ′
On the basis of a next-to-leading-order calculation in chiral perturbation theory, the first complete analysis of isospin breaking for direct $CP$ violation in ${K}^{0}\ensuremath{\rightarrow}2\ensuremath{\pi}$ decays is performed. We find a destructive interference between three different sources of isospin violation in the $CP$ violation parameter ${ϵ}^{\ensuremath{'}}$. Within the uncertainties of large-${N}_{c}$ estimates for the low-energy constants, the isospin violating correction for ${ϵ}^{\ensuremath{'}}$ is below 15%.
pi(0)-pi mixing and CP violation
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.
Electromagnetism in nonleptonic weak interactions
16 páginas, 1 figura.-- PACS: 11.30.Rd; 13.25.Es; 13.40.Ks.-- arXiv:hep-ph/0006172v2
3-Neutrino Mass Spectrum from Combining Seesaw and Radiative Neutrino Mass Mechanisms
We extend the Standard Model by adding a second Higgs doublet and a right-handed neutrino singlet with a heavy Majorana mass term. In this model, there are one heavy and three light Majorana neutrinos with a mass hierarchy m_3 >> m_2 >> m_1 such that that only m_3 is non-zero at the tree level and light because of the seesaw mechanism, m_2 is generated at the one-loop and m_1 at the two-loop level. We show that the atmospheric neutrino oscillations and large mixing MSW solar neutrino transitions with $��m^2_\mathrm{atm} \simeq m_3^2$ and $��m^2_\mathrm{solar} \simeq m_2^2$, respectively, are naturally accommodated in this model without employing any symmetry.
Anomalous non-leptonic kaon decays
8 páginas, 1 figura.
The pionic beta decay in chiral perturbation theory
Within the framework of chiral perturbation theory with virtual photons and leptons, we present an updated analysis of the pionic beta decay including all electromagnetic contributions of order e**2 p**2. We discuss the extraction of the Cabibbo-Kobayashi-Maskawa matrix element |Vud| from experimental data. The method employed here is consistent with the analogous treatment of the Kl3 decays and the determination of |Vus|.
Kaon Decays in the Standard Model
A comprehensive overview of kaon decays is presented. The Standard Model predictions are discussed in detail, covering both the underlying short-distance electroweak dynamics and the important interplay of QCD at long distances. Chiral perturbation theory provides a universal framework for treating leptonic, semileptonic and nonleptonic decays including rare and radiative modes. All allowed decay modes with branching ratios of at least 10^(-11) are analyzed. Some decays with even smaller rates are also included. Decays that are strictly forbidden in the Standard Model are not considered in this review. The present experimental status and the prospects for future improvements are reviewed.
Non-Leptonic Kaon Decays and the Chiral Anomaly
32 páginas, 3 figuras, 4 tablas.-- El PDF es el artículo publicado en el CERN en Junio de 1993.