34 research outputs found
Lagrangians for Massive Dirac Chiral Superfields
A variant for the superspin one-half massive superparticle in , , based on Dirac superfields, is offered. As opposed to the
current known models that use spinor chiral superfields, the propagating fields
of the supermultiplet are those of the lowest mass dimensions possible: scalar,
Dirac and vector fields. Besides the supersymmetric chiral condition, the Dirac
superfields are not further constrained, allowing a very straightforward
implementation of the path-integral method. The corresponding superpropagators
are presented. In addition, an interaction super Yukawa potential, formed by
Dirac and scalar chiral superfields, is given in terms of their component
fields. The model is first presented for the case of two superspin one-half
superparticles related by the charged conjugation operator, but in order to
treat the case of neutral superparticles, the Majorana condition on the Dirac
superfields is also studied. We compare our proposal with the known models of
spinor superfields for the one-half superparticle and show that it is
equivalent to them.Comment: 22 pages. Matches published versio
Dynamical seesaw mechanism for Dirac neutrinos
So far we have not been able to establish that, as theoretically expected,
neutrinos are their own anti-particles. Here we propose a dynamical way to
account for the Dirac nature of neutrinos and the smallness of their mass in
terms of a new variant of the seesaw paradigm in which the energy scale of
neutrino mass generation could be accessible to the current LHC experiments.Comment: 7 pages, 1 figur
String completion of an electroweak model
The extended electroweak
symmetry framework "explaining" the number of fermion families is revisited.
While -based schemes can not easily be unified within the conventional
field theory sense, we show how to do it within an approach based on D-branes
and (un)oriented open strings, on Calabi-Yau singularities. We show how the
theory can be UV-completed in a quiver setup, free of gauge and string
anomalies. Lepton and baryon numbers are perturbatively conserved, so neutrinos
are Dirac-type, and their lightness results from a novel TeV scale seesaw
mechanism. Dynamical violation of baryon number by exotic instantons could
induce neutron-antineutron oscillations, with proton decay and other dangerous
R-parity violating processes strictly forbidden.Comment: 12 pages, 2 figures, published versio
Three-family left-right symmetry with low-scale seesaw mechanism
We suggest a new left-right symmetric model implementing a low-scale seesaw
mechanism in which quantum consistency requires three families of fermions. The
symmetry breaking route to the Standard Model determines the profile of the
"next" expected new physics, characterized either by the simplest left-right
gauge symmetry or by the 3-3-1 scenario. The resulting gauge bosons
can be probed at the LHC and provide a production portal for the right-handed
neutrinos. On the other hand, its flavor changing interactions would affect the
K, D and B neutral meson systems.Comment: 10 pages, 2 figures. Revised version as accepted by JHE
A Model of Comprehensive Unification
Comprehensive - that is, gauge and family - unification using spinors has
many attractive features, but it has been challenged to explain chirality.
Here, by combining an orbifold construction with more traditional ideas, we
address that difficulty. Our candidate model features three chiral families and
leads to an acceptable result for quantitative unification of couplings. A
potential target for accelerator and astronomical searches emerges.Comment: 5 pages, 2 figures. Published versio
Electron-positron annihilation into phi f_{0}(980) and clues for a new 1^{--} resonance
We study the e^{+}e^{-} to phi pi pi reaction for pions in an isoscalar
s-wave which is dominated by loop mechanisms. For kaon loops we start from the
conventional RCHPT, but use the unitarized amplitude for KbarK-pipi scattering
and the full kaon form factor instead of the lowest order terms. We study also
effects of vector mesons using RCHPT supplemented with the conventional
anomalous term for VVP interactions and taking into account the effects of
heavy vector mesons in the K*K transition form factor. We find a peak in the
dipion invariant mass around the f_{0}(980) as in the experiment. Selecting the
phi f_{0}(980) contribution as a function of the e^{+}e^{-} energy we also
reproduce the experimental data except for a narrow peak, yielding support to
the existence of a 1^{--} resonance above the phi f_{0}(980) threshold,
coupling strongly to this state.Comment: 18 pages, 4 figure