8,850,045 research outputs found
Flavor Delta(54) in SU(5) SUSY Model
We design a supersymmetric SU (5) GUT model using \Delta (54), a finite
non-abelian subgroup of SU (3)f . Heavy right handed neutrinos are introduced
which transform as three-dimensional repre-sentation of our chosen family
group. The model successfully reproduces the mass hierarchical mass structures
of the Standard Model, and the CKM mixing matrix. It then provides predictions
for the light neutrino with a normal hierarchy and masses such that m{\nu},1
\approx 5\times10-3 eV, m{\nu}, 2 \approx 1\times 10-2 eV, and m{\nu},3 \approx
5 \times 10-2 eV. We also provide predictions for masses of the heavy
neutrinos, and correc- tions to the tri-bimaximal matrix that fit within
experimental limits, e.g. a reactor angle of -7.31o. A simple modification to
our model is introduced at the end and is shown to also produce predictions
that fall well within those limits.Comment: 22 page
The Cowl - v.54 - n.5 - Oct 18, 1989
The Cowl - student newspaper of Providence College. Volume 54, Number 5 - October 18, 1989. 20 pages
Pulsar Parallaxes at 5 GHz with the Very Long Baseline Array
We present the first pulsar parallaxes measured with phase-referenced pulsar
VLBI observations at 5 GHz. Due to the steep spectra of pulsars, previous
astrometric measurements have been at lower frequencies. However, the strongest
pulsars can be observed at 5 GHz, offering the benefit of lower combined
ionospheric and tropospheric phase errors, which usually limit VLBI astrometric
accuracy. The pulsars B0329+54, B0355+54 and B1929+10 were observed for 7
epochs spread evenly over 2 years. For B0329+54, large systematic errors lead
to only an upper limit on the parallax (pi < 1.5 mas). A new proper motion and
parallax were measured for B0355+54 (pi = 0.91 +- 0.16 mas), implying a
distance of 1.04+0.21-0.16 kpc and a transverse velocity of 61+12-9 km/s. The
parallax and proper motion for B1929+10 were significantly improved (pi = 2.77
+- 0.07 mas), yielding a distance of 361+10-8 pc and a transverse velocity of
177+4-5 km/s. We demonstrate that the astrometric errors are correlated with
the angular separation between the phase reference calibrator and the target
source, with significantly lower errors at 5 GHz compared to 1.6 GHz. Finally,
based on our new distance determinations for B1929+10 and B0355+54, we derive
or constrain the luminosities of each pulsar at high energies. We show that,
for thermal emission models, the emitting area for X-rays from PSR B1929+10 is
roughly consistent with the canonical size for a heated polar cap, and that the
conversion of spin-down power to gamma-ray luminosity in B0355+54 must be low.
The new proper motion for B1929+10 also implies that its progenitor is unlikely
to have been the binary companion of the runaway O-star zeta-Ophiuchi.Comment: 8 pages, including 3 figures and 3 tables; emulateapj; ApJ submitte
2006 Vol. 54 No. 5
https://engagedscholarship.csuohio.edu/lawpublications_gavel2000s/1031/thumbnail.jp
2006 Vol. 54 No. 5
https://engagedscholarship.csuohio.edu/lawpublications_gavel2000s/1031/thumbnail.jp
- …