39329664
One-loop-induced fermion masses and exotic interactions in a standard-model context.
The standard SU(2)\ifmmode\times\else\texttimes\fi{}U(1) electroweak gauge model is extended to include a fourth generation of quarks and leptons as well as four extra Higgs-boson doublets. With the implementation of a ${Z}_{4}$ discrete symmetry, which is softly broken down to ${Z}_{2}$, realistic radiative quark and lepton masses for the first two generations can be obtained. Assuming that the third and fourth lepton generations are odd under the unbroken ${Z}_{2}$, we discuss a number of interesting phenomenological consequences such as a longer $\ensuremath{\tau}$ lifetime and some possible anomalous $\ensuremath{\tau}$ interactions. We also single out some processes involving fourth-generation quarks and leptons which cannot be confused experimentally with those of the standard model.
40901564
Dichotomy of leptons: Radiative masses and rare decays.
A model is presented where the electron and muon masses are radiative and depend, respectively, on the masses of {tau} and a fourth charged lepton {ital E}. A discrete {ital Z}{sub 4} symmetry is softly broken down to {ital Z}{sub 2} which distinguishes ({mu},{tau}) from ({ital e},{ital E}). All three known neutrinos acquire radiative Majorana masses.
115458701
The Asymmetric Left-Right Electroweak Gauge Model
7343393
Asymmetric left-right model for generating radiative quark and lepton masses.
The conventional SU(2){sub {ital L}}{times}SU(2){sub {ital R}}{times}U(1) electroweak gauge model is extended to include two heavy singlet quarks and one heavy singlet lepton. The scalar sector consists of two (2,1,1/2) doublets, two (1,2,1/2) doublets, one (2,1,3/2) doublet, one (1,2,3/2) doublet, as well as one (1,3,1) triplet. Realistic radiative masses for all light quarks and leptons are obtained. A {ital Z}{sub 2} discrete symmetry serves to distinguish the electron (or muon) and its neutrino from the other leptons.
121842859
TWO-BODY RADIATIVE GLUINO DECAYS
A gluino can decay into a color-singlet neutral fermion by radiating off a gluon. We study this process in a minimal supersymmetric extension of the standard model. A significant branching fraction is possible depending on how much overlaps with the Higgs fermion which couples to the t quark and the mass of the t quark itself.
121009870
Muon-electron transitions in models of radiative lepton masses
In models where both the electron and muon acquire radiative masses, the same mechanism often allows μ-e transitions as well at a certain level. We discuss the phenomenological constraints on some recently proposed models of this type and show that they are incompatible with present experimental limits on μ→eγ, and in one case also μ→eee, without the fine tuning of parameters which these models are supposed to avoid.
42663006
Search for neutrinoless double- beta decay in 136Xe with a time projection chamber.
A xenon time projection chamber (TPC) with an active volume of 180 liters has been built to study neutrinoless double-β decay in 136 Xe. The experiment was performed in the Gotthard Underground Laboratory, with 5 atm of xenon enriched to 62.5% in 136 Xe. The experimental details, background considerations, detector performance, and data analysis are discussed. From 6830 h of data, no evidence has been found for the 0v 0 + → 0 + transition. Half-life limits of T 1/2 0v > 3.4(6.4) × 10 23 yr in the mass mechanism mode, and T 1/2 0v > 2.6(4.9) × 10 23 yr in the right-handed currents mode, at the 90(68)% C.L., were derived, corresponding to an upper limit on the Majorana neutrino mass parameter of about 2.8 eV