18208373
Neutrino mixing due to a violation of the equivalence principle.
Massless neutrinos will mix if their couplings to gravity are flavor dependent, i.e., violate the principle of equivalence. Because the gravitational interaction grows with neutrino energy, the solar neutrino problem and the recent atmospheric neutrino data may be simultaneously explained by violations at the level of 10[sup [minus]14] to 10[sup [minus]17] or smaller. This possibility is severely constrained by present accelerator neutrino experiments and will be preeminently tested in proposed long-base-line accelerator neutrino experiments.
122900794
Spontaneous symmetry breaking in scale invariant quantum electrodynamics
Abstract Quantum electrodynamics is studied analytically in a quenched, planar approximation in four dimensions. At sufficiently strong coupling, chiral symmetry is broken spontaneously and the corresponding pseudoscalar Goldstone boson is observed. This phase of the theory is governed by a novel ultraviolet fixed point which requires the mixing of four-fermion interactions with the electrodynamic interactions.
117357229
Further Investigation on Chiral Symmetry Breaking in a Uniform External Magnetic Field
We study chiral symmetry breaking in QED when a uniform external magnetic field is present. We calculate higher order corrections to the dynamically generated fermion mass and find them to be small. In so doing we correct an error in the literature regarding the matrix structure of the fermion self-energy.
7271721
Properties of the dilaton.
Gauge models which possess a hierarchy of mass scales may exhibit a pseudo-Goldstone boson, the dilaton, of the scale symmetry. Properties of the dilaton are studied in a technicolor model, where the technifermion chiral condensation scale differs from the confinement scale. The dilaton exhibits properties very similar to the elementary Higgs boson of the standard model. It is distinguished from the Higgs boson by its Goldstone nature, which is manifested in an enhanced multidilaton production. Estimates for the dilaton mass and lifetime are given and various production mechanisms are discussed. Prospects for detecting the dilaton in its associated production with W or Z and in W and Z decays are stressed.
119894314
Neutral massive leptons in an SO(10) model with massless neutrinos
The neutral massive leptons expected in SO(10) have been studied in a model which permits neutrinos to be massless. The mixing of these leptons with ordinary neutrinos introduces violations of weak universality. Three massive leptons occur: ${N}_{1}$, coupling to $\ensuremath{\mu}$ and ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ with strength ($0.026 \frac{\mathrm{GeV}}{{M}_{{N}_{1}}}$) relative to the ordinary weak coupling; ${N}_{2}$, coupling to $\ensuremath{\tau}$ and ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ with relative strength ($1.8 \frac{\mathrm{GeV}}{{M}_{{N}_{2}}}$); and ${N}_{3}$, coupling to $\ensuremath{\mu}$ and ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ with relative strength ($1.8 \frac{\mathrm{GeV}}{{M}_{{N}_{3}}}$) and to $\ensuremath{\tau}$ and ${\ensuremath{\nu}}_{\ensuremath{\tau}}$ with relative strength ($8 \frac{\mathrm{GeV}}{{M}_{{N}_{3}}}$). Their masses are bounded from below by 0.37, 6, and 25 GeV, respectively. The prospects for observing the neutral massive leptons in neutrino neutral-current interactions, in $W$ and $Z$ decays, and in $\ensuremath{\tau}$, $c$, and $b$ decays are discussed.
15944513
Neutrino oscillations from string theory
Abstract We derive the character of neutrino oscillations that results from a model of equivalence principle violation suggested recently by Damour and Polyakov as a plausible consequence of string theory. In this model neutrino oscillations will take place through interaction with a long range scalar field of gravitational origin even if the neutrinos are degenerate in mass. The energy dependence of the oscillation length is identical to that in the conventional mass mixing mechanism. This possibility further highlights the independence of and need for more exacting direct neutrino mass measurements together with a next generation of neutrinoless double beta decay experiments.
16983943
Wave propagation in gravitational systems: Late time behavior.
It is well known that the dominant late time behavior of waves propagating on a Schwarzschild spacetime is a power-law tail; tails for other spacetimes have also been studied. This paper presents a systematic treatment of the tail phenomenon for a broad class of models via a Green's function formalism and establishes the following. (i) The tail is governed by a cut of the frequency Green's function G\ifmmode \tilde{}\else \~{}\fi{}(\ensuremath{\omega}) along the -Im\ensuremath{\omega} axis, generalizing the Schwarzschild result. (ii) The \ensuremath{\omega} dependence of the cut is determined by the asymptotic but not the local structure of space. In particular it is independent of the presence of a horizon, and has the same form for the case of a star as well. (iii) Depending on the spatial asymptotics, the late time decay is not necessarily a power law in time. The Schwarzschild case with a power-law tail is exceptional among the class of the potentials having a logarithmic spatial dependence. (iv) Both the amplitude and the time dependence of the tail for a broad class of models are obtained analytically. (v) The analytical results are in perfect agreement with numerical calculations.
16884927
Late-time tail of wave propagation on curved spacetime.
The late time behavior of waves propagating on a general curved spacetime is studied. The late time tail is not necessarily an inverse power of time. Our work extends, places in context, and provides understanding for the known results for the Schwarzschild spacetime. Analytic and numerical results are in excellent agreement.