143 research outputs found
Method for the Self-Consistent Determination of Regge Pole Parameters
A method is suggested for approximately bootstrapping Regge trajectories, thereby avoiding the cutoff problems of the usual bootstrap calculation. The method is based on dispersion relations for Regge trajectories and on unitarity applied at l=α. Successively more realistic approximations are described which bring in more information on the potential, and more trajectories. The approximate Regge parameters are guaranteed to have the desired threshold and asymptotic properties
Regge trajectories versus vanishing renormalization constants as dynamical criteria
The connection between continuous Regge trajectories and the vanishing of renormalization constants is explored. It is found that if, in a field theory Z1→0 and Z3→0 in such a way that Z1/Z3→0, then a Regge trajectory moves smoothly under an elementary particle pole so that the particle becomes dynamical in the Regge sense. Thus a bootstrapped world may perhaps equally well be defined by its satisfying a field theory with all renormalization constants set equal to zero, as by saying that all particles lie on Regge trajectories
Large Lepton Mixings from Continuous Symmetries
Within the broad context of quark-lepton unification, we investigate the
implications of broken continuous family symmetries which result from requiring
that in the limit of exact symmetry, the Dirac mass matrices yield hierarchical
masses for the quarks and charged leptons, but lead to degenerate light
neutrino masses as a consequence of the seesaw mechanism, without requiring
hierarchical right-handed neutrino mass terms. Quark mixing is then naturally
small and proportional to the size of the perturbation, but lepton mixing is
large as a result of degenerate perturbation theory, shifted from maximal
mixing by the size of the perturbation. Within this approach, we study an
illustrative two-family prototype model with an SO(2) family symmetry, and
discuss extensions to three-family models.Comment: 23 page
On Neutrinos and Fermionic Mass Patterns
Recent data on neutrino mass differences are consistent with a hierarchical
neutrino mass structure strikingly similar to what is observed for the other
fermionic masses.Comment: 8pages, 2figure
The breaking of the flavour permutational symmetry: Mass textures and the CKM matrix
Different ansaetze for the breaking of the flavour permutational symmetry
according to S(3)L X S(3)R in S(2)L X S(2) give different Hermitian mass
matrices of the same modified Fritzsch type, which differ in the symmetry
breaking pattern. In this work we obtain a clear and precise indication on the
preferred symmetry breaking scheme from a fit of the predicted theoretical Vckm
to the experimentally determined absolute values of the elements of the CKM
matrix. The preferred scheme leads to simple mass textures and allows us to
compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner
angles of the unitarity triangle in terms of four quark mass ratios and only
one free parameter: the CP violating phase Phi. Excellent agreement with the
experimentally determined absolute values of the entries in the CKM matrix is
obtained for Phi = 90 deg. The corresponding computed values of the Jarlskog
invariant and the inner angles are J = 3.00 X 10^-5, alpha= 84 deg, beta= 24
deg and gamma =72 deg in very good agreement with current data on CP violation
in the neutral kaon-antikaon system and oscillations in the B-Bbar system.Comment: 21 pages, 1 fig. Content enlarged, references added and typos
corrected. To be published in Phys Rev
A Tumbling Top-Quark Condensate Model
We propose a renormalizable model with no fundamental scalars which breaks
itself in the manner of a "tumbling" gauge theory down to the standard model
with a top-quark condensate. Because of anomaly cancellation requirements, this
model contains two color sextet fermions (quixes), which are vector-like with
respect to the standard model gauge group. The model also has a large number of
pseudo-Nambu-Goldstone bosons, some of which can be light. The top-quark
condensate is responsible for breaking the electroweak gauge symmetry and gives
the top quark a large mass. We discuss the qualitative features and instructive
shortcomings of the model in its present form. We also show that this model can
be naturally embedded into an aesthetically pleasing model in which the
standard model fermion families appear symmetrically.Comment: 16 pages. v2: TeX formatting fixed, no other change
Model of the Quark Mixing Matrix
The structure of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is analyzed from
the standpoint of a composite model. A model is constructed with three families
of quarks, by taking tensor products of sufficient numbers of spin-1/2
representations and imagining the dominant terms in the mass matrix to arise
from spin-spin interactions. Generic results then obtained include the familiar
relation , and a less frequently
seen relation . The magnitudes of
and come out naturally to be of the right order. The phase in
the CKM matrix can be put in by hand, but its origin remains obscure.Comment: Presented by Mihir P. Worah at DPF 92 Meeting, Fermilab, November,
1992. 3 pages, LaTeX fil
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