Rishon Model Research Articles

Diagrammatics in the Rishon model

We give diagrammatic rules within the rishon model to implement the low-energy electroweak phenomenology. They result from an analysis of the important differences between neutral and charged currents owing to their different origin at the rishon or composite levels. They suggest some general constraints on any possible rishon dynamics.

'T Hooft's anomaly constraint in the rishon model

We apply 't Hooft's anomaly constraint and flavour independence requirement to the rishon model. The limit g c→0 is taken and we assume the full flavour symmetry SU(6) L × SU(6) R to be partially broken to SU(3) L × SU(3) R. Anomaly equations are constructed in the preserved global flavour symmetry, which have a simple solution of one generation of massless quarks.

Bosons in the rishon model

All bosons are assumed to be built by rishons. The gravitation appears as a mixture of ( rr rr ) states, acting only on composite fermions, while the mediating bosons between single rishons in a lepton or quark are ( rr ) states.

Generations in the rishon model

We present a model for fermions composed of rishons in which colour plays a determinant role providing for only three generations. The couplings with the gauge bosons of the SU(2) L × SU(2) R × U(1) B−L theory as well as with Higgs bosons are determined by the colour substructures. Two appealing possibilities emerge: the Cabibbo mixing angles could be small due to their dependence on the colour coupling constant and the fermionic mass hierarchy could be related to the fact that the products of higher representations have a richer decomposition allowing for the coupling with more Higgs fields.

Generation labels in composite models for quarks and leptons

We consider models in which quarks and leptons are approximately massless composites of fundamental massless fermions which are confined by a hypercolor force. The fundamental lagrangian exhibits an axial U(1) X symmetry which is broken by hypercolor instantons, leaving a conserved discrete subgroup. We propose that the distinction between different generations of quarks and leptons is given by the X-number. The resulting generation labelling scheme does not lead to massless Goldstone bosons or to new anomalies and is based on a quantum number which is already contained in the theory. The dynamical rishon model is described as an illustrative example.

A new subquark model: a variation of the rishon model

A new subquark model: a variation of the rishon model

Dynamical symmetry breaking and composite quarks and leptons

We propose a new mechanism for dynamical symmetry breaking in composite models of quarks and leptons. We assume that quarks and leptons are hypercolor-singlet composites of fundamental fermions which are bound by hypercolor forces. Composite leptons exhibit a short-range residual hypercolor force, similar to hadron-hadron interactions which are residual color forces. Two leptons can form scalar condensates at the hypercolor distance scale. These scalars provide an attractive pattern of dynamical symmetry breaking. The rishon model is an explicit example of such a pattern.

A dynamical theory for the rishon model

We propose a composite model for quarks and leptons based on an exact SU(3) C × SU(3) H gauge theory and two fundamental J= 1 2 fermions: a charged T-rishon and a neutral V-rishon. Quarks, leptons and W-bosons are SU(3) H-singlet composites of rishons. A dynamically broken effective SU(3) C × SU(2) L × SU(2) R × U(1) B− L gauge theory emerges at the composite level. The theory is “natural”, anomaly free, has no fundamental scalar particles, and describes at least three generations of quarks and leptons.

Rishon model of quarks and leptons with double SU(2) symmetry and Dirac magnetic moments

Two-doublet rishon models are proposed to avoid some of the kinematic and dynamic difficulties of the single-doublet rishon model. One has point-like magnetic moments only for leptons. The other, based on an anti-pairing hypothesis, has point-like leptons and quarks.