Hidden Higgs Particle

A modification of the standard model of electroweak interactions with the nonlocal Higgs sector is proposed. Proper form of nonlocality makes Higgs particles unobservable after the electroweak symmetry breaking. They appear only as a virtual state because their propagator is an entire function. We discuss some specific consequences of this approach comparing it with the conventional standard model.Comment: 15 pages, LaTeX, no figure

Lepton number, black hole entropy and 10 to the 32 copies of the Standard Model

Lepton number violating processes are a typical problem in theories with a low quantum gravity scale. In this paper we examine lepton number violation (LNV) in theories with a saturated black hole bound on a large number of species. Such theories have been advocated recently as a possible solution to the hierarchy problem and an explanation of the smallness of neutrino masses. Naively one would expect black holes to introduce TeV scale LNV operators, thus generating unacceptably large rates of LNV processes. We show, however, that this does not happen in this scenario due to a complicated compensation mechanism between contributions of different Majorana neutrino states to these processes. As a result rates of LNV processes are extremely small and far beyond experimental reach, at least for the left-handed neutrino states.Comment: 6 pages, 3 figures, to appear in Proc. PASCOS 2010, Valencia, Spai

Longitudinal vector form factors in weak decays of nuclei

The longitudinal form factors of the weak vector current of particles with spin $J = 1/2$ and isospin $I = 1/2$ are determined by the mass difference and the charge radii of members of the isotopic doublets. The most promising reactions to measure these form factors are the reactions with large momentum transfers involving the spin-1/2 isotopic doublets with a maximum mass splitting. Numerical estimates of longitudinal form factors are given for nucleons and eight nuclear spin-1/2 isotopic doublets.Comment: 6 pages. Talk given at the 10th MEDEX'15 meeting Matrix Elements for the Double-beta-decay Experiments, Prague, June 9-12, 201

Leptoquarks: Neutrino masses and accelerator phenomenology

Leptoquark-Higgs interactions induce mixing between leptoquark states with different chiralities once the electro-weak symmetry is broken. In such LQ models Majorana neutrino masses are generated at 1-loop order. Here we calculate the neutrino mass matrix and explore the constraints on the parameter space enforced by the assumption that LQ-loops explain current neutrino oscillation data. LQs will be produced at the LHC, if their masses are at or below the TeV scale. Since the fermionic decays of LQs are governed by the same Yukawa couplings, which are responsible for the non-trivial neutrino mass matrix, several decay branching ratios of LQ states can be predicted from measured neutrino data. Especially interesting is that large lepton flavour violating rates in muon and tau final states are expected. In addition, the model predicts that, if kinematically possible, heavier LQs decay into lighter ones plus either a standard model Higgs boson or a $Z^0/W^{\pm}$ gauge boson. Thus, experiments at the LHC might be able to exclude the LQ mechanism as explanation of neutrino data.Comment: 28 pages, 10 figure