The main subject is to clarify various properties of quarks and leptons described by
their unified pictures based on unification of the quark-lepton interactions and by their
substructure based on compositeness of the quark-lepton states. Currently studied
are possible forms of new interactions.and possible types of other fundamental particles
than quarks and leptons including their subconstituents as the extension of the
Glashow-Weinberg-Salam model for
the standard quark-lepton physics. Also focused
on are their phenomenological implications in various high-energy experiments such as
collisions at FNAL
and ep collisions at HERA.
Future planned collisions such as those at
LHC,
CLIC and JLC. The previously studied works have been published in
several journals, which are listed as the publication list.
The recent results are summarized as new results.
Our laboratory has received and will receive financial support from the
Ministry of Education, Culture, Sports, Science, and Technology, Japan, supplied
by ."Grants-in-Aid for Scientific Research":
Weak interactions of quarks and leptons and their
compositeness
The symmetric behavior of quarks and leptons that manifests itself in
weak interactions was described as the manifestation of effects caused by more
fundamental particles,
Weak interactions of quarks and leptons and the anomalies in
neutral current interactions
The systematic analyses and predictions on the anomalies of neutral
current interactions were performed.
Compositeness of quarks and leptons implied by an SO(10)
unified model
A new model was proposed to describe composite quarks and leptons in
accord with the SO(10) group structure.
Mass scales in an SO(10) unified model of quarks and leptons
The mass scales at the spontaneous breakdown the SO(10) symmetry
are determined by the stability of the Higgs potential. And applications to
quark-lepton physics were described.
Observable effects due to quark-lepton compositeness
Physics of composite quarks and leptons was discussed as possible
observed effects in experiments, which appeared as deviations of the standard model
predictions due to their finite sizes.
The Nambu-Goldstone mechanism for quark-lepton compositeness
The Nambu-Goldstone mechanism in supersymmetric theories were suggested
as the mass generation mechanism of light quarks and leptons. Especially, mass
formula of Nambu-Goldstone fermions were derived as the supersymmetric version of the
Dashen formula..
Masses of quarks and leptons and nonlinear interactions
Detailed calculations of quark-lepton masses were performed by adopting
nonlinear interaction of the Nambu-Jona-Lasinio type as explicit mechanism of creating
composites.
Extra weak bosons and charge-commutation relations
Sum rules of masses of weak bosons including extra weak bosons were
derived from commutation relation of weak charges in the electroweak SU(2)xU(1)
model.
Mass protection mechanisms and mass hierarchies of quarks and
leptons
The interplay of chiral symmetries and supersymmetry as mass protection
mechanisms was applied to construct supersymmetric models for quarks and leptons
exhibiting mass hierarchies.
Compositeness of extra weak bosons and their phenomenology
Excited weak bosons were introduced as matter fields, which were
related to weak bosons as gauge fields. The derived interactions were applied
to predict possible physics of extra weak bosons at
and
collisions.
Masses of quarks and leptons and
supersymmetric quantum chromodynamics
A possible mechanism of generating light composite fermions was
suggested by utilizing Nambu-Goldstone supermultiplets in supersymmetric quantum
chromodynamics (SQCD). The symmetry breaking patterns were clarified in SQCD with N"flavor">N"color"
based on an effective lagrangian approach of the
Veneziano-Yankielowicz
type. Some of these breakings produced Nambu-Goldstone supermultiplets including
quark-lepton fields, whose low-energy interactions were thus computed by the effective
lagrangian. The explicit breaking terms of chiral symmetries and supersymmetry
were also included in the effective lagrangian to predict quark-lepton masses. The
relation of symmetry breaking patterns obtained by our research to those conjectured by
Dr.Seiberg is
currently studied.
Compositeness and
"elementariness"
Composite weak bosons were pointed out to disguise as fundamental gauge
particles at low-energies below compositeness scale. Also discussed is the similar
phenomenon in QCD with three flavors, where octet vector bosons were regarded as octet
color massive gluons and the same procedure was applied to extra weak bosons in the QCD
with the SU(2) "color",
Properties of strange matter
The relationship of mass number and electric charge of strange matter
was discussed to derive mass formula, which was applied to the candidate events due to
strange matter.
Radiatively generated neutrino masses
Neutrinos are kept massless at the tree level. Their masses are
radiatively generated by one loop diagrams. 1)The model is extended
to include the fourth hypothetical neutrino called "sterile neutrino" that is
used to accont for oscillations of the electron neurtinos comming from the Sun.2)This
radiative mechaniism is naturally incorporated in models based on SU(3)LXU(1)N
and the suggested physics on creation of neutrino mass is examined.
CP-violation in
neutrinos
New sources of CP-violation arise from complex masses of
neutrinos and are should be clarified.
-
Properties of neutrino
oscillations compatible with the observation
Constraints on flavor neutrino masses are generally
derived for large neutrino mixing and neutrino mass hierarchiy..
