We study the overlap and the fixed point Dirac operators for massive fermions in the two-flavor lattice Schwinger model. The masses of the triplet (pion) and singlet (eta) bound states are determined down to small fermion masses and the mass dependence is compared with various continuum model approximations. Near the chiral limit, at very small fermion masses the fixed point operator has stabil...

We analyze a model of Semi-Direct Gauge Mediation in which the hidden sector is the 4-1 model and the messenger fields are charged under the U(1) gauge group. At tree level, the SUSY-breaking F-terms induce D-terms from which SUSY-split messenger masses arise. We calculate these masses by three complementary methods. Additionally, we compute the one-loop corrections to the masses. We consider t...

We propose an extension of the supersymmetric standard model with righthanded neutrinos and a singlet Higgs field, and study the neutrino masses in this model. The Majorana masses for the right-handed neutrinos are generated around the supersymmetry breaking scale through the vacuum expectation value of the singlet Higgs field. This model may induce spontaneous R-parity violation via the vacuum...

Framework-based Object-Oriented applications are not as eecient as they could be. This results from the high-genericity of frameworks. However, once the framework is instantiated, part of this genericity can be removed. This is for instance the case when gener-icity is obtained through the use of reeection. This paper takes the Java Serialization framework as a typical example and shows how par...

1. de Jong MD, Hien TT. Avian infl uenza A (H5N1). J Clin Virol. 2006;35:2–13. 2. World Health Organization. Epidemic and pandemic alert and response: confi rmed human cases of avian infl uenza A (H5N1). [cited 2007 Apr 23]. Available from http:// www.who.int/csr/disease/avian_infl uenza/ country/en/index.html 3. Dinh PN, Long HT, Tien NTK, Hien NT, Mai LTQ, Phong LH, et al. Risk factors for hu...

We propose an extension of the supersymmetric standard model with righthanded neutrinos and a singlet Higgs field, and study the neutrino masses in this model. The Majorana masses for the right-handed neutrinos are generated around the supersymmetry breaking scale through the vacuum expectation value of the singlet Higgs field. This model may induce spontaneous R-parity violation via the vacuum...

We propose a model for neutrino mass generation in wich no physics beyond a TeV is required. We extend the standard model by adding two charged singlet fields with lepton number two. Dirac neutrino masses mνD ≤ MeV are generated at the one loop level. Small left handed majorana neutrino masses can be generated via the seesaw mechanism with right handed neutrino masses MR are of order TeV scale....

A. Introduction This note discusses some of the theoretical issues relevant for the determination of quark masses, which are fundamental parameters of the Standard Model of particle physics. Unlike the leptons, quarks are confined inside hadrons and are not observed as physical particles. Quark masses therefore cannot be measured directly, but must be determined indirectly through their influen...

We first discuss an approach to the fermion mass problem, according to which the whole of flavour mixing for quarks is determined by the mechanism responsible for generating the physical masses of the up and down quarks: the Lightest Flavour Mass Generation model. Then we consider fermion masses in the Anti-grand Unification Theory and, in particular, the neutrino mass and mixing problem. To be...