48 research outputs found
General Properties of the Decay Amplitudes for Massless Particles
No full textWe derive the kinematical constraints which characterize the decay of any massless particle in flat spacetime. We show that in perturbation theory the decay probabilities of photons and Yang-Mills bosons vanish to all orders; the decay probability of the graviton vanishes to one-loop order for graviton loops and to all orders for matter loops. A general power counting argument indicates in which conditions a decay of a massless particle could be possible: the lagrangian should contain a self-coupling without derivatives and with a coupling constant of positive mass dimension
General Properties of the Decay Amplitudes for Massless Particles
No full textWe derive the kinematical constraints which characterize the decay of any massless particle in flat spacetime. We show that in perturbation theory the decay probabilities of photons and Yang-Mills bosons vanish to all orders; the decay probability of the graviton vanishes to one-loop order for graviton loops and to all orders for matter loops. A general power counting argument indicates in which conditions a decay of a massless particle could be possible: the lagrangian should contain a self-coupling without derivatives and with a coupling constant of positive mass dimension
General Properties of the Decay Amplitudes for Massless Particles
No full textWe derive the kinematical constraints which characterize the decay of any massless particle in flat spacetime. We show that in perturbation theory the decay probabilities of photons and Yang-Mills bosons vanish to all orders; the decay probability of the graviton vanishes to one-loop order for graviton loops and to all orders for matter loops. A general power counting argument indicates in which conditions a decay of a massless particle could be possible: the lagrangian should contain a self-coupling without derivatives and with a coupling constant of positive mass dimension
Simple circuit and experimental proposal for the detection of gauge-waves
Get PDFAharonov-Bohm electrodynamics predicts the existence of traveling waves of
pure potentials, with zero electromagnetic fields, denoted as gauge waves, or
g-waves for short. In general, these waves cannot be shielded by matter since
their lack of electromagnetic fields prevents the material from reacting to
them. However, a not-locally-conserved electric current present in the material
does interact with the potentials in the wave, giving the possibility of its
detection. In [F.M., G.M., Eur.Phys.J. C 83, 1086 (2023)] the basic theoretical
description of a detecting circuit was presented, based on a phenomenological
theory of materials that can sustain not-locally-conserved electric currents.
In the present work we discuss how that circuit can be built in practice, and
used for the effective detection of g-waves.Comment: 12 pages, 2 figure
Theoretical analysis of a reported weak-gravitational-shielding effect
No full textUnder special conditions (Meissner-effect levitation in a high-frequency
magnetic field and rapid rotation) a disk of high-Tc superconducting
material has recently been found to produce a weak shielding of the
gravitational field. We show that this phenomenon has no explanation in
the standard gravity theories, except possibly in the non-perturbative
Euclidean quantum theory
Generalized Maxwell equations and charge conservation censorship
No full text The Aharonov–Bohm electrodynamics is a generalization of Maxwell theory with reduced gauge invariance. It allows to couple the electromagnetic field to a charge which is not locally conserved, and has an additional degree of freedom, the scalar field [Formula: see text], usually interpreted as a longitudinal wave component. By reformulating the theory in a compact Lagrangian formalism, we are able to eliminate S explicitly from the dynamics and we obtain generalized Maxwell equation with interesting properties: they give [Formula: see text] as the (conserved) sum of the (possibly non-conserved) physical current density [Formula: see text], and a “secondary” current density [Formula: see text] which is a nonlocal function of [Formula: see text]. This implies that any non-conservation of [Formula: see text] is effectively “censored” by the observable field [Formula: see text], and yet it may have real physical consequences. We give examples of stationary solutions which display these properties. Possible applications are to systems where local charge conservation is violated due to anomalies of the Adler–Bell–Jackiw (ABJ) kind or to macroscopic quantum tunnelling with currents which do not satisfy a local continuity equation. </jats:p
