Keiichi Akama

Observable effects of the possible sub-structure of leptons and quarks

Abstract Some observable effects of the possible sub-structure of leptons and quarks are discussed in subquark models of leptons and quarks. They include (1) possible deviations of the anomalous magnetic moments of leptons (and quarks) from the QEWD (and QCD) predictions, (2) possible deviations of the weak charged currents of leptons (and quarks) from the V-A form and (3) possible existence of the excited states of leptons and quarks as well as those of gauge bosons and Higgs scalars.

Gravity and Electromagnetism as Collective Phenomena of Fermion-Antifermion Pairs

A generally covariant formulation is made for the previously proposed unified model of the Nambu-Jona-Lasinio type for gravity and electromagnetism. The gravitational and electro-magnetic fields are generated as collective excitations of fermion-antifermion pairs. The modl is shown to be effectively equivalent to the Einstein-Weyl theory of general relativity. The G-α relation, the relation between the fine structure constant and the Newtonian gravitational constant is re-derived.

Dynamical subquark model of pregauge and pregeometric interactions

Abstract A dynamical subquark model of leptons and quarks in which both gauge bosons and gravitons (or the space-time metric) are composites of a subquark-antisubquark pair is presented and discussed. Yang-Mills gauge theory and Einsteins general relativity appear as effective theories.

Topological pregauge-pregeometry

Abstract The pregauge-pregeometric action, i.e. the fundamental matter action whose quantum fluctuations give rise to the Einstein-Hilbert and the Yang-Mills actions, is investigated from the point of view of the topological field theory. We show that the scalar pregauge-pregeometric action is a topological invariant for appropriate choices of the internal gauge group. This model realizes the picture that the gravitational and internal gauge theory at the low energy scale is induced as the quantum effects of the topological field theory at the Planck scale.

Compositeness condition at the next-to-leading order in the Nambu-Jona-Lasinio model.

We investigate the compositeness condition in four dimensions at the nontrival order (next-to-leading order in 1/{ital N}, with {ital N} the number of colors), taking the Nambu{endash}Jona-Lasinio model as an example. In spite of its nonrenormalizability, the compositeness condition can be successfully derived and solved in compact forms. The resultant problems are discussed. {copyright} {ital 1996 The American Physical Society.}

Pregeometric origin of the big bang

The temperature-dependent effective action for gravity is calculated in pregeometry. It indicates that the effective potential for the space-time metric has the minimum at the origin for extremely high temperature. The origin of the big bang can be taken as a local and spontaneous phase transition of the space-time from the pregeometric phase to the geometric one.

Towards BRST quantization of pregeometry and topological pregeometry

Abstract We investigate the Dirac bracket algebra of the scalar pregeometry including topological pregeometry with BRST formalism, as the first step to its quantization. We examine unitarity of the S-matrix, derive the precise expression for induced gravity, and discuss how the gravity is induced from the topological theory.

Naturalness bounds on dipole moments from new physics

Assuming naturalness that the quantum corrections to the mass should not exceed the order of the observed mass, we derive and apply model-independent bounds on the anomalous magnetic moments and electric dipole moments of leptons and quarks due to new physics.

Subquark pregeometry with spontaneously broken conformal invariance

Abstract We present a model of subquark pregeometry in which the Higgs scalar as well as the space-time metric appears as a composite of subquark-antisubquark pairs. The effective langrangian becomes the einstein one with no cosmological term when conformal invariance is broken spontaneously.

Quark mixings in a subquark model

Abstract Quark mixings and theor momentum dependences are discussed in a subquark model in which the weak current is made of the iso-doublet spinor subquarks. The Cabibbo angle is predicted to become larger as momentum transfer between quarks grows up.