Although we know that spontaneous symmetry breaking occurs, because M~, M E ~ 0, we do not yet know the underlying physics or understand what happens. So far, no reasonably attractive theoretical picture has emerged at all, let alone been tested by experiment. Essentially no experiment has put significant constraints on the existence or masses or interactions of scalar or pseudoscalar bosons, a...

The present lectures contain an introduction to low energy supersymmetry, a new symmetry that relates bosons and fermions, in particle physics. The Standard Model of fundamental interactions is briefly reviewed, and the motivation to introduce supersymmetry is discussed. The main notions of supersymmetry are introduced. In more detail the supersymmetric extension of the Standard Model the Minim...

We study the decays of a standard model-like MSSM Higgs boson to pairs of neutralinos, each of which subsequently decays promptly to a photon and a gravitino. Such decays can arise in supersymmetric scenarios where supersymmetry breaking is mediated to us by gauge interactions with a relatively light gauge messenger sector (Mmess . 100TeV). This process gives rise to a collider signal consistin...

We consider the possibility that muon number conservation is not a fundamental symmetry of nature. In simple SU(2) @ U(1) gauge theories with several scalar boson doublets, muon number will still automatically be conserved by the intermediate vector boson interactions, but not by effects of virtual scalar bosons. The branching ratio for p -L ey is estimated to be of order (a/~)~. Other p-e tran...

K → ππ decays are investigated in the framework of the SU (2) L × U (1) gauge theory of J = 0 mesons proposed in [1], to which is added an interaction between mesons respecting the two symmetries generally attributed to strong interactions, flavour symmetry and parity conservation. It is shown that the damping of the K + → π + π 0 amplitude with respect to the ones of K s → ππ results from a ca...

Abstract We systematically discuss the consequences of genuine dimension-six Higgs operators. These operators are not subject to stringent constraints from electroweak precision data. However, they can modify the couplings of the Higgs boson to electroweak gauge bosons and, in particular, the Higgs self-interactions. We study the sensitivity to which those couplings can be probed at future ee l...

We study spontaneous scalarization in Scalar-Tensor boson stars. We find that scalarization does not occur in stars whose bosons have no self-interaction. We introduce a quartic self-interaction term into the boson Lagrangian and show that when this term is large, scalarization does occur. Strong self-interaction leads to a large value of the compactness (or sensitivity) of the boson star, a ne...

Superselection rules induced by the interaction with a mass zero Boson field are investigated for a class of exactly soluble Hamiltonian models. The calculations apply as well to discrete as to continuous superselection rules. The initial state (reference state) of the Boson field is either a normal state or a KMS state. The superselection sectors emerge if and only if the Boson field is infrar...

All members of a recently proposed new set of (non-supersymmetric) grand unified theories with at the one-loop level vanishing beta functions for the gauge, Yukawa, and scalar-boson self-interaction coupling constants are shown to involve, already at the one-loop level, quadratically divergent contributions to both the vector-boson and scalar-boson masses.