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A. C. Melissinos

Publications and source records attributed to A. C. Melissinos.

8 recordsLinked to original sources
arXiv2002

A "Running" Gravitational Constant?

If the gravitational interaction is unified with the electroweak and strong interactions at a mass M=10^15 GeV, the evolution of Newton's constant must differ from its classical (general relativistic) form. We can model such behavior by introducing an ad hoc dependence on ln(s/4m^2) where s is the usual cm energy between two protons. We can then predict the observable effects for relativistic collisions (sqrt(s)~1.4x10^4 GeV) as well as for the case of low velocity motion (beta^2~10^-5)

hep-ph↗
arXiv2002

Measuring the Phase Velocity of Light in a Magnetic Field with the PVLAS Detector

A method is suggested for measuring the velocity of light in a magnetic field using the PVLAS detector. It is proposed to modulate the linear polarization of the input light. In that case the feedback signal necessary to keep the high finesse Fabry-Perot cavity on resonance is a measure of the change in the speed of light for the two orthogonal polarizations.

hep-ph↗
arXiv2001

Neutrino Scattering in a Magnetic Field

Motivated by the evidence for a finite neutrino mass we examine anew the interaction of neutrinos in a magnetic field. We present the rate for radiative scattering for both massless and massive neutrinos in the standard model and give the corresponding numerical estimates. We also consider the effects arising from a possible neutrino magnetic moment.

hep-ph↗
arXiv2000

Compression of High-Charge Electron Bunches

The A0 Photoinjector at Fermilab can produce high charge (10-14 nC) electron bunches of low emittance (20 pi mm-mrad for 12 nC). We have undertaken a study of the optimal compression conditions. Off-crest acceleration in the 9-cell capture cavity induces an energy-time correlation, which is rotated by the compressor chicane (4 dipoles). The bunch length is measured using streak camera images of optical transition radiation. We present measurements under various conditions, including the effect of the laser pulse length (2 ps sigma Gaussian vs. 10 ps FWHM flat top). The best compression to date is for a 13.2 nC bunch with sigma = 0.63 mm (1.89 ps), which corresponds to a peak current of 2.8 kA.

physics.acc-ph↗
arXiv2000

Electro-Optic Sampling of Transient Fields from the passage of High-Charge Electron Bunches

When a relativistic electron bunch traverses a structure, strong electric fields are induced in its wake. We present measurements of the electric field as a function of time as measured at a fixed location in the beam line. For a 12 nC bunch of duration 4.2 ps FWHM, the peak field is measured >0.5 MV/m. Time resolution of ~5 ps is achieved using electro-optic sampling with a lithium tantalate (LiTaO_3) crystal and a short-pulse infrared laser synchronized to the beam. We present measurements under several different experimental conditions and discuss the influence of mode excitation in the structure.

physics.acc-ph↗
arXiv1998

The Spontaneous Breakdown of the Vacuum

We discuss the spontaneous breakdown of the vacuum by a strong electromagnetic field as observed in SLAC experiment E-144. We show that the data follow the Schwinger non-perturbative result obtained for a static field.

hep-ph↗