Local scale invariance as a fundamental symmetry of Nature is proposed. This necessitates the existence of a new vector boson associated with local scale invariance. The new boson is referred to as the Weylon. The local gauge action is taken to be that of the Standard Model with SU(3) x SU(2) x U(1) gauge symmetry. For gravitational interactions, two actions are considered, one linear in curvature and the other quadratic in torsion. In both types of theories breaking of the local gauge and scale invariance is achieved through the usual doublet of scalars and leads to massive vector bosons with the remarkable result that all Higgs degrees of freedom are entirely eliminated. In both models, the Weylon acquires a mass of around 10(19)GeV.

The role of magnetic fields during the initial stages of protostellar cloud collapse is investigated, in particular with respect to the scenario where the magnetic force can be an effective compressor due to diamagnetic effects. A multifluid approach involving electrons, ions of different atomic masses and neutrals is adopted, where each species is treated separately The electron fluid is compressed by the magnetic pressure force, and the other ion species are pulled by the collective electric field developed by the space charge separation. The neutrals are also dragged owing to collisions with the ions. The difference in charge-to-mass ratio ensures that each ion species is accelerated differently resulting in a distribution following their atomic masses. This model explores the scenario where the electromagnetic forces can achieve a supercritical mass-to-flux ratio in a magnetized cloud before dynamical collapse due to gravity takes over.

It is shown that the usual algebraic structure of the commutation and anticommutation relations of the N = 1 conformal superalgebra can be extended to include additional terms. These terms transform as parity odd under the discrete symmetry operation associated with parity. The constraints resulting from the Jacobi identities required for the consistency of the extended algebraic structure are also given. One Limiting case of the algebra is shown to reduce to the algebra of Kaku, van Nieuwenhuizen and Townsend.

We present a simple extension of the standard model of electroweak interactions that accommodates existing and recent data on neutrinos. The model contains a scalar triplet carrying two units of lepton number and a vector-like neutral lepton in addition to the usual bosons and fermions of the standard model. The model also accounts for the hot dark matter component required in mixed dark matter models that attempt to solve the large scale structure problem.

This working group report focuses on the physics potential of μ^+μ^- colliders beyond what can be accomplished at linear e^+e^- colliders and the LHC. Particularly interesting possibilities include (i) s-channel resonance production to discover and study heavy Higgs bosons with ZZ and WW couplings that are suppressed or absent at tree-level (such as the H and A Higgs bosons of supersymmetric models), (ii) study of the strongly interacting electroweak sector, where higher energies give larger signals, and (iii) measurements of the masses and properties of heavy supersymmetric particles.

We study T violation at a mu(+)mu(-) collider in the reaction mu(+)mu(-) --> mu(+)mu(-) This is achieved by introducing complex gauge interactions in the leptonic sector of the standard model. T violating asymmetries analogous to the usual P violating asymmetry in conventional weak interactions are defined. The study requires measurements of the polarisations of the mu(+), mu(-) beams in the initial and final states. Whilst these are difficult experiments, nevertheless it may be possible to set stringent upperbounds on T violating amplitudes in the leptonic sector from studies of these asymmetries at mu(+)mu(-) colliders.

This working group report focuses on the physics potential of µ + µ − colliders beyond what can be accomplished at linear e + e − colliders and the LHC. Particularly interesting possibilities include (i) s-channel resonance production to discover and study heavy Higgs bosons with ZZ and W W couplings that are suppressed or absent at tree-level (such as the H and A Higgs bosons of supersymmetric models), (ii) study of the strongly interacting electroweak sector, where higher energies give larger signals, and (iii) measurements of the masses and properties of heavy supersymmetric particles.

An SU(2)L×SU(2)R×U(1)B×U(1)l model is described in which abelian gauge symmetries are associated with the observed conservation in nature of baryon and lepton numbers. The model is anomalous. An interesting way to cancel the triangle anomalies of the three families of quarks and leptons in the model is to invoke leptoquark matter which is new fermionic matter that carries baryon as well as lepton numbers. In addition to the standard neutral boson (Z°), the theory predicts two massive neutral gauge bosons. The lower bounds on their masses are in the few hundred GeV mass range which makes these particles prospective candidates for production at the LHC and the SSC.

The N = 4 Super Yang-Mills theory remains finite if mass terms for the scalars and fermion are introduced explicitly by hand provided these terms satisfy the mass-squared supertrace sum rule. SIGMA/j=0, 1/2 (-1)2-J+1 M(J)2(2J + 1) = 0.It is shown that the sum rule emerges from the elimination of quadratic divergences in the one-loop effective potential of the theory.

It is shown that the gauge fixing lagrangian density of the form Lgf = −(12β)(ϖ·A)(ϖ2)2(ϖ·A) leads to a class of Landau-like gauges in which the wave function renormalization of the spinor field is one. We discuss the result in the case of spinor electrodynamics and in the case where the vector field Aμ acquires mass through the Higgs mechanism. The Landau gauge result is recovered in the limit β→0. The non-abelian situation is also alluded to.

Voloshin, Vysotski and Okun have suggested that the apparent anticorrelation between the solar-neutrino flux and the sun-spot number can be understood if the electron neutrino has magnetic moment in the range 10−11–10−10 μB. The conventional left-right symmetric model of electroweak interactions is ideally suited for the electron neutrino o acquire a magnetic moment of this order if the model is supplemented with Zee's charged singlet Higgs. However, the problem of reconciling naturally the large value of the magnetic moment with the neutrino mass in the eV range still persists in the model.

A model of electroweak interactions is presented in which quarks transform the quark-matter electroweak symmetry ${G}^{q}={\mathrm{SU}(2)}_{L}^{q}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{Y}^{q}$ and leptons transform under the leptonic-matter electroweak symmetry ${G}^{l}={\mathrm{SU}(2)}_{L}^{l}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{Y}^{l}$. The standard electroweak interactions are the diagonal sum of ${G}^{q}\ifmmode\times\else\texttimes\fi{}{G}^{l}$ interactions resulting from spontaneous symmetry breaking. In this model the charged and neutral bosons behaving like the $W$ and $Z$ of the standard model have mass lower bounds of order 1 TeV while there exists the possibility of an additional massive neutral boson with mass as low as 150 GeV.

The hypercharge ${\mathrm{U}(1)}_{Y}$ of the standard electroweak model is split into chiral hypercharges ${\mathrm{U}(1)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{R}$. Under the new gauge symmetry ${\mathrm{SU}(2)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{R}$, quarks and leptons are left-handed doublets transforming only under ${\mathrm{SU}(2)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{U}(1)}_{L}$ and right-handed singlets transforming only under ${\mathrm{U}(1)}_{R}$. Consistent with the measurements of the mass of the standard massive neutral boson ${Z}^{0}$ at the SLAC and CERN colliders and the neutral-current couplings involving neutrino beams and electron beams, the additional massive neutral gauge boson can be as light as a few hundred GeV. The model utilizes the generalized see saw mechanism of Gell-Mann, Ramond, and Slansky to give masses to all the fermions of the theory.

The possibility that gauge symmetries associated with baryon and lepton numbers are spontaneously broken symmetries of nature is entertained. In this endeavor, the gauge group of electroweak interactions is SU(2)\ifmmode\times\else\texttimes\fi{}U${(1)}^{3}$. Consistent with neutral-current phenomenology, the spectrum of massive neutral gauge bosons consist of the ${Z}^{0}$ of the standard electroweak model and two additional neutral bosons with mass lower bounds of 120 and 210 GeV which makes these particles prospective candidates for production in the energy regimes of the CERN LEP, Fermilab Tevatron, and the Superconducting Super Collider.

Discrete symmetries associated with the roots of unity are employed to construct Fritzsch-type mass matrices for the three generations of fermions in the standard model with SU(3)\ifmmode\times\else\texttimes\fi{}SU(2)\ifmmode\times\else\texttimes\fi{}U(1) gauge symmetry. The model requires four conventional Higgs doublets to account for the hierarchy of fermion masses and mixings.

We consider nonrelativistic composite models for quarks and leptons. We determine the constraints which arise, in order that theg value for both the quarks and the leptons, as well as the preons should be equal to 2. We present models which are consistent with our constraints.

Strong and electroweak interactions may be a relic of the spontaneous breakdown of a chirally symmetric colour-flavour gauge group. The minimum possibility of such a structure that is symmetric between left and right is SU(3)L×SU(3)R×SU(2)L×SU(2)R×U(1)B−L where quantum chromodynamics originates in the chiral colour group SU(3)L×SU(3)R and the electroweak interaction originates in the ambidextrous electroweak interaction group SUL×SU(2)R×U(1)B− L. The chiral anomalies are cancelled by adding a set of fermions that transform as singlets under the weak interaction group SU(2)L×SU(2)R. This model requires only three Higgs representations to break the proposed gauge symmetry to SU(3)C×U(1)em and give masses to all the quarks and leptons of the theory. All fermion masses are “see-saw” masses.

By considering the symmetries associated with baryon number and lepton number conservation as gauge symmetries, the underlying gauge symmetry of weak electromagnetic interactions is shown to beSU(2) L ×U(1)×U(1)Baryon×U(1)Lepton. If right-handed currents exist on a par with the observed left-handed ones, then the full symmetry of electroweak interactions that emerges isSU(2)L×SU(2)R×U(1)Baryon×U(1)Lepton. These symmetries offer a rich spectrum of massive neutral gauge bosons, one of which is the massive neutral boson of the standardSU(2) L ×U(1) Y model.

An ambidextrous electroweak interaction model with SU(2${)}_{\mathrm{L}}$\ifmmode\times\else\texttimes\fi{}SU(2${)}_{\mathrm{R}}$\ifmmode\times\else\texttimes\fi{}U(1) gauge symmetry is described in which the conventional quarks and leptons are accompanied by a set of new fermions that transform as singlets of SU(2${)}_{\mathrm{L}}$ and SU(2${)}_{\mathrm{R}}$. Only two doublets of Higgs scalars are introduced to break the gauge symmetry SU(2${)}_{\mathrm{L}}$\ifmmode\times\else\texttimes\fi{}SU(2${)}_{\mathrm{R}}$\ifmmode\times\else\texttimes\fi{}U(1) to U(1) of electromagnetism. The masses of all known quarks and leptons result from the Gell-Mann, Ramond, and Slansky ``see-saw mechanism'' between the conventional fermions and the new ``singlet'' fermions. The definition of the Fermi coupling constant and neutrino neutral-current interactions are identical to those of the standard SU(2${)}_{\mathrm{L}}$\ifmmode\times\else\texttimes\fi{}U(1) model. The singlet fermion masses lie in the 100-GeV to 1-TeV range to be probed by the oncoming accelerators of the 1990s.