R. Casalbuoni

Effective Weak Interaction Theory with Possible New Vector Resonance from a Strong Higgs Sector

Abstract We consider the effective lagrangian for electroweak interactions in the limit of a strong interacting Higgs sector ( m H → ∞). We assume that the appearing SU(2) v hidden local symmetry is realized through a new dynamical vector boson resonance V. We derive the physical admixtures and masses of W, Z and V bosons and calculate the couplings of the physical bosons to fermions. No physical Higgs remains in the spectrum. We find that the standard low energy phenomenology of weak interactions, as well as the W-, Z-masses and properties, may be rather closely reproduced in our effective theory, even for low values of the mass of the new vector resonance, within presently accessible energies.

Relatively and supersymmetries

Abstract We show how the supersymmetry transformations follow from the relativization of a pseudoclassical lagrangian describing particles with spin.

Physical implications of possible J = 1 bound states from strong Higgs

Abstract A strongly interacting Higgs sector could give rise to new bound states. Among them, spin-1 bosonic states would, through their mixing with γ, W and Z, significantly modify some phenomenological predictions. For a first attempt at describing such a situation we have employed the local hidden symmetry formulation of the non-linear σ-model, used as a simulation of the strong Higgs sector, and have conjectured the appearance of the boson kinetic term. The relatively simple description that we obtain allows for a calculation of the mixing and couplings, for a fit of all the low-energy phenomenology, and for a discussion of the experimental predictions. In particular, we find that accurate measurements of the W and Z masses could permit a test of these ideas.

Classical scalar and spinning particles interacting with external Yang-Mills fields

Abstract We derive the classical equations of motion for scalar and spinning particles interacting with an external Yang-Mills field. The internal degrees of freedom are described by a set of Grassmann variables; in this way, after quantization, we get automatically finite-dimensional representations of the internal symmetry group. By requiring that the Lagrangian is gauge invariant we determine the general form for the coupling terms. In particular we obtain a generalized version of the Bargmann-Michel-Telegdi equation, which is valid for a spin - 1 2 particle in an arbitrary external field.

Subcomponent models of quarks and leptons

Abstract We investigate what models can be invented by thinking of quarks and leptons as composites of spin- 1 2 subcomponents confined into singlets of a new SU(3) (subcolor). We are led to six solutions, three of them allowing for family classification. We discuss quantum numbers and subcomponent rearrangement reactions, such as proton decay.

Classical spinning particles interacting with external gravitational fields

Abstract In this paper we study the coupling between the pseudoclassical spinning particle and an arbitrary gravitational field. The gravitational field is treated as a gauge field in order to deal with possible contributions from the torsion of space-time. We find that the spinning particle cannot be coupled directly to the torsion. We study the classical equations of motion which turn out to be the same as derived by Papapetrou in order to describe the so called pole-dipole singularity in general relativity. We discuss also the structure of the energy-momentum tensor for the spinning particle.

Dirac Propagator From Path Integral Quantization of the Pseudoclassical Spinning Particle

Abstract We show how the Dirac propagator can be reproduced by summing over the paths of a pseudoclassical spinning particle.

Strong interacting two-doublet and doublet-singlet Higgs models☆

Abstract The possible violation of tree-level unitarity is examined within the standard model with two scalar doublets or a doublet plus a singlet, whenever one (or more) Higgs masses are sufficiently large. Limitations on the model from radiative corrections to the ϱ-value and from flavor conservation are taken into account. In particular for the two-doublet model, with discrete reflection symmetry guaranteeing natural flavor conservation. It is found that tree-level unitarity is violated earlier than for the single doublet model.

The IOSp(D, 2>38;|2) symmetry from the BRST quantization of the relativistic spinning particle

Abstract We present the BRST quantization of the relativistic spinning particle. We show that, as in the case of the relativistic scalar particle recently studied by Neveu and West, the Poincare symmetry in D dimensions extends to an IOSp( D , 2|2) symmetry. The origin of this enlargement comes from the extra dynamical variables and ghosts necessary to describe the extended phase space. This space is spanned by the original dynamical variables plus the lagrangian multipliers associated to the first-class constraints plus their conjugated momenta. A new feature arises due to the presence in the theory of an anticommuting first-class constraint (the one giving the Dirac equation), which requires the introduction of an anticommuting Lagrange multiplier. From this follows that the wave function must be Grassman-valued leading to a unique choice of anticommunitation relations for the Dirac field in the second quantized theory.

Quantized Grassmann variables and unified theories

Abstract The color and flavor degrees of freedom are described in terms of Fermi oscillators (quantized Grassmann variables). The unified theories constructed in this way are vector-like. The fundamental fermions come out to be classified in the spinorial representations of the orthogonal groups.