On the excited quarks and leptons

Using a duality-like finite energy sum rule, we discuss the assumption of having excited fermions at the W scale in a supersymmetric(SUSY) and non-supersymmetric hypercolour theory where quarks and leptons are bound states of fermion and scalar preon constituents. We conclude that a SUSY-like composite model cannot have excited fermions having a mass smaller than 0.5 TeV. A non-SUSY composite model having composite fermions but elementary W bosons can produce an excited fermion mass of the order of M_W provided that the scalar vacuum condensate is of the order of the (TeV)² scale of compositeness.     

Composite fermions in Suzuki's preon model

We consider fermions in the preon model invented by Suzuki to describe electroweak vector bosons as composite objects. It turns out that composite fermions are in this model very heavy and cannot be interpreted as the ordinary quarks and leptons. This is the case both in Suzuki's original theory and in a modified theory introduced in this paper.     

SU(9) GRAND UNIFIED PREON MODEL SATISFYING COMPLEMENTARITY

We constructed an SU(9) grand unified preon model which satisfies the complementarity principle between Higgs phase and confining phase.The model ends up with the prediction of four generations of quarks and leptons,and an appropriate hypercolor scale.     

COMPOSITE QUARK MASS HIERARCHY AND FCNC SUPPRESSION

The observed quark mass hierarchy and the realistic mixing matrix of quark charged currents may be explained in a framework of a three-fermion composite model, if the quark masses are generated by the condensaties of exotic colored fermions and in the dynamical mechanism, we incorporate the following conjecture that the four-preon hypercolor condensates, which are used to realize the spontaneous breaking of the family gauge group su^F(2) in the model, may correspond to two different mass scales. We also show that all the FCNC including the |ΔS|=2 effective coupling in the model can be suppressed down to below the experimental limit.     

Families,the invisible axion,and domain walls

We consider models in which the unbroken discrete subgroup of a Peccei-Quinn symmetry may be effectively embedded in the rest of the continuous symmetry group to avoid the formation of domain walls. In this context we may gain insight into the family question. We note that instantons in an unbroken “hypercolor” group might be used to reduce the size of the discrete symmetry or to eliminate it altogether.     

A SUPERSYMMETRICAL PREON MODEL WITH SU(2)L × SU(2)R ×U(1)B-L SYMMETRY BROKEN BY COUPLING TO SUPERGRAVITY

A supersymmetrical preon model is proposed. In this model there are Higgs particles which are massless at the scale of confinement of hypercolor due to the supersymmetry and a discrete R symmetry. We show that in this model the low energy gauge symmetry SU(2)_L×SU(2)_R×U(1)_B-L can be broken to U(1)_Q at the scale of supersymmetry breaking by coupling to supergravity.     

Yang-Mills instantons and the S-matrix

We present a scheme for calculating gauge-invariant S-matrix elements in the presence of instantons. We exploit the conformal invariance of the zero-mass field equations. The asymptotic in and out states are defined by their values on null infinity $\text{J}$. We use this method to calculate to lowest-order S-matrix elements for scalar particles and fermions in a dilute gas of SU(2) instantons and anti-instantons. The scalar particles acquire an effective mass and an effective interaction of the form $\text{exp}\text{(?(?}{}^2\text{/16π) ?}\text{?}\text{)}$, where ? is the scale of the instanton, plus other interactions which cannot be presented by a local effective lagrangian. The fermions acquire the effective lagrangian obtained by 't Hooft. In the case of a single flavour of fermions, this corresponds to a mass term.     

Two dimensional gases of weight charges and SU(N) fermino theories

We analyze two dimensional gases composed of particles interacting via a Coulomb or Yakawa potential through their “non-Abelian” charges. These charges are taken to be elementary weight or root vectors of SU(N). The grand partition function of these gases is shown to be equivalent to the generating functional of sine-Gordon models with weight vectors and hence to that of SU(N) fermion models. The fermion field creates or annihilates topological solitons which have elementary weight vectors as topological quantum numbers. Then, we discuss the confinement of fermions in the SU(N) Higgs models, where instantons (Z_N vortices) constitute a Yukawa gas of weight charges. We prove that fermions are confirmed by the effects of instantons in the SU(N) Higgs models in contrast with the Abelian Higgs model.     

THE COMPOSITE MODEL OF LEPTON AND QUARK WITH ONLY ONE CONSTITUENT SCALAR

We propose a composite model of leptons and quarks containing two constituent fermions of spin 1/2 and a constituent scalar. The constituent fermions are massless and color singlets. Leptons, quarks and weak vector bosons are composites confined by SU(3)_H local gauge interaction, where leptons are made of three constituent fermions and quarks are two-body composites of a scalar and a fermion. The number of the constituent particles is less in our model. There are less exotic leptons and quarks. Quark-lepton parallelism holds. Weak interactions appear only at the composite level as residual short-range interactions among hypercolor singlets. The violation of parity occurs by the mechanism of dynamical symmetry breaking.     

Supersymmetric subconstituents and the problem of mass

We assume that two mechanisms operate to protect the masslessness of fermions in a subconstituent theory: (a) the matching of chiral anomalies, (b) the combination of supersymmetry and the spontaneous breaking of a flavor symmetry. In a toy supersymmetric hyperchromodynamical model based on SU(10) hypercolor we illustrate the interplay of these mechanisms.     

Generation of the Effective Fermion Vertex by a Gravitational Instanton in Lattice Gravity Theory

JETP Letters - It has been shown that effective fermion vertices appear in lattice gravity associated with fermions. These vertices are generated by gravitational instantons, similar to the...     

FACTORIZATION OF SUC(3) AT HYPERCOLOR SCALE ∧H AND INDUCED GOLDSTONE BOSONS IN COMPOSITE MODELS

The two possibilities (corresponding to various spontaneous breaking patterns for hyperflavor) for the color group SU_C(3) factorized at the hypercolor scale ∧_H for a kind of composite models are discussed, in which the color inferaction is asymptotically non-free on the preon level, and it is pointed out that the two patterns could be distinguished experimentally by the great difference in number of the induced pseudogoldstones.     

Quasi nambu-goldstone fermions

We explore in detail the hypothesis that quarks and leptons are the approximately massless quasi Goldstone fermions of a supersymmetric preon theory. In particular, we discuss the possible patterns of states emerging from the spontaneous breakdown of global symmetries in supersymmetric theories and construct the low-energy effective lagrangians describing the interaction of these states. In contrast to what happens in the Goldstone sector, the interactions of the quasi Goldstone fermions contain arbitrary parameters which directly reflect the preon dynamics. Various models are explored, including both models in which the weak interactions are residual and models where these interactions are fundamental. A variety of issues are addressed, from the universality and approximate SU(2)_L nature of the weak interactions, for the former class of models, to the generation of states beyond the quarks and leptons and the nature of the dynamical breaking of SU(2)_L×U(1), for the latter class of models. Open questions and speculations connected with the origin of families and the nature of fermion mass generation, including supersymmetry breaking, are also discussed.     

Weak interactions of quasi nambu-goldstone fermions

We investigate the hypothesis that the observed weak interactions are the residual interactions of quasi Goldstone fermions. Left-handed quarks and leptons arise from the spontaneous symmetry breaking U(6) → U(4) × SU(2) in a supersymmetric theory. The simplest preon model realizing this breakdown leads, in the complementary picture, to the supersymmetric extension of the standard model of electroweak interactions. Furthermore, 't Hooft's anomaly conditions are satisfied with respect to the unbroken subgroup of the U(6) flavour symmetry and R-invariance. The preon model predicts the existence of a ninth chiral supermultiplet, the novino.     

FOUR-FERMION SU(N)HYPERCOLOR CONDENSATES AND THEIR MASS SCALES

It is conjectured and shown by means of the screening Casimir effective couplings among fer-mions that,the four-fermivn condensates<(ff)²> formed through the SU(N).hypercolor gauge interac-tions,in geneial,may always have two forming paths which respectively correspond to different mass scales, and only for some special SU(N) representations of the fermions f the condensates have one mass scale or no four-fermion condensate could be formed.     

Complementarity in preon models with E6 metacolor

Tumbling complementarity is studied in chiral preon models based on the metacolor group E₆. By considering the breaking of E₆ into each maximal little group in the Higgs phase, several models are found that are in accord with complementarity. Three families of massless fermions (on the metacolor scale) can be obtained, but so far we have been unable to identify an E₆ × SU(N) preon model supported by complementarity that correctly predicts the quantum numbers of ordinary quarks and leptons.     

SU(2) × U(1) breaking by vacuum misalignment

Currently two scenarios exist which explain SU(2) × U(1) breaking: the Higgs mechanism, and standard hypercolor schemes. In this paper, a third scenario called “oblique hypercolor” is proposed. A hyperquark condensate is formed which, although kinematically allowed to point in an SU(2) × U(1) preserving direction, is forced by Yukawa interactions of the hyperquarks to misalign by a small angle, breaking SU(2) × U(1). The low energy spectrum involves normal fermions with correct masses, a partially composite Higgs boson, and physical charged scalars.     

The structure of weak interactions for composite quarks and leptons

We consider a model of quarks and leptons as quasi-Goldstone fermions which is based on an underlying supersymmetric SU(2)_HC × SU(2)′_HC preon theory. The spontaneous breakdown of a global U(6) × U(6)′ × U(1) symmetry to U(4) × U(4)′ × SU(2)_diag creates both quarks and leptons and at the same time allows for the possibility of having either residual or fundamental weak interactions. Effective lagrangians in the confining phase of the theory are compared to those emerging from a complementary picture and the problems connected with the nature of the weak interactions are discussed in this context also.     

Enhancement of Higgs to diphoton decay width in non-perturbative Higgs model

We investigate a possibility if a loop diagram via Higgsino can enhance the Higgs to diphoton decay width in supersymmetric models with an extension of Higgs sector. A model with an additional non-renormalizable term of Higgs fields is firstly analyzed where the higher order term can introduce the Higgs coupling to Higgsinos as well as charged Higgs bosons. We point out that a choice of the Higgs coupling to obtain a significant size of enhancement of diphoton decay width reduces the Higgs mass and/or a size of non-renormalizable term needs to be large and a cutoff scale is around the weak scale. Another model in which the Higgsino mass term is generated by a non-perturbative instanton effect via a strong dynamics in a context of SUSY QCD is also suggested. It is shown that the sign of the Higgs coupling to fermions is opposite from perturbative models due to an operator including bosonic fields in the denominator and a constructive contribution to the diphoton decay amplitude can be easily obtained in this kind of model.     

Quasibosons

The similarity of the commutation relations for bosons and quasibosons (fermion pairs) suggests the possibility that all integral spin particles presently considered to be bosons could be quasibosons. The boson commutation relations for integral spin particles could be just an approximation to the quasiboson commutation relations that contain an extra term. Although the commutation relations for quasibosons are slightly more complex, it is a simpler picture of matter in that only fermions and composite particles formed of fermions exist. Mesons are usually referred to as bosons, but they must be quasibosons since their internal structure is fermion (quark) pairs. The photon is usually considered to be an elementary boson, but as shown here, existing experiments do not rule out the possibility that it is also a quasiboson. We consider how the quasiboson, composite nature of such a photon might manifest itself.