Neutrino mass generation with extra right-handed fields in a Dirac scenario via the type-I seesaw mechanism

An extension of the Standard Model (SM) is studied in which two right-handed (RH) neutrinos per generation are incorporated, but considering the hypothesis of the symmetry of lepton and quark contents in order to deprive the number of RH neutrinos of freedom, generate Dirac neutrinos and accommodate naturally tiny values for their masses. The high scale type-I seesaw regime is applied to the first, ordinary RH neutrino, whereas a low scale pseudo-Dirac scenario is used for the second, adulterant RH neutrino, implying that the first RH neutrino decouples at the high scale, while the second RH neutrino survives down to the low scale to pair off in a Dirac-like form with the corresponding left-handed (LH) neutrino. The small mass and couplings of this extra RH neutrino are explained by means of the statement of the symmetry of fermionic content, only regarded as a guideline to the natural choice of parameters since it is not a proper symmetry in the Lagrangian.Comment: 12 page

Chern-Simons-fermion model of quarks

We propose an extension of the standard model where quarks are viewed as fermions with a ``bare'' integer (weak) hypercharge which is normalized with a fractional part created by a quantized topological Chern-Simons configuration of the weak gauge fields. Consistency with hypercharge patterns not included in the standard model is shown.Comment: 4 pages, Revtex, no figure

Unification of standard and exotic matter through a Z2Z_2 symmetry

We consider a scenario in which the discrete weak symmetry between quarks and leptons is extended to the weak force by introducing exotic partners. We conjecture that there exists a hidden discrete symmetry $\tilde{P}$, defining a $Z_2$ group, between standard and exotic quarks and leptons. The unified model $SU(3)_{q} \times SU(3)_{\tilde{q}} \times SU(2)_{q \tilde{\ell}} \times SU(2)_{\tilde{q} \ell} \times U(1)_{Y} \times \tilde{P}$ is discussed, where the unifying discrete symmetry extends over particles and forces. It is shown that the lighter neutral and charged weak bosons generated upon spontaneous symmetry breaking have the same properties as those of the standard model. Cabbibo-Kobayashi-Maskawa unitarity is used to set a mass of order 2.8 TeV for the nonstandard weak bosons, which do not exhibit quark-lepton universality. A grand unified theory of $GUT_{q \tilde{\ell}} \times GUT_{\tilde{q} \ell} \times \tilde{P}$ type, with decay of exotic matter into standard matter and no decay of the ordinary nucleon, is put forward.Comment: 6 pages, no figure

Electroweak quark-lepton symmetry and weak topological-charge confinement in the Standard Model with Dirac neutrinos

The standard electroweak model with Dirac neutrinos is extended by way of the principles of electroweak quark-lepton symmetry and weak topological-charge confinement to account for quark-lepton charge relations which, if not accidental, are indicative of charge structures. A mixing in quarks and leptons of underlying integer local charges with integer weak topological charges associated with an additive group Z_3, fixed by the anomaly cancellation requirement, is discussed. It is found that the electroweak difference between topological quarks and leptons is the nonequivalence between the topological vacua of their weak field configurations, produced by a four-instanton which carries the topological charge, induces the universal fractional piece of charge distinguishing quarks from leptons, and breaks the underlying symmetry. The constituent quarks of the standard model appear as coming from topological quarks, via the weak four-instanton event. Dual transitions occur for leptons. It is shown that several other fundamental problems left open in the standard electroweak model with Dirac neutrinos are solved: the one-to-one correspondence between quark and lepton flavors, the existence of three generations, the conservation and ungauging of B-L, the electric charge quantization, and the confinement of fractional electric charges.Comment: 23 pages, 1 figure, uses IJMPA.cl