18,441 research outputs found
OAO-2 observations of beta Lyrae and a provisional interpretation
Six-color ultraviolet photoelectric observations of beta Lyrae obtained with OAO-2 are presented. These observations, made at 1380, 1500, 1920, 2460, 2980 and 3330 A, represent the first truly continual coverage of the light changes of beta Lyrae during one orbital revolution and were obtained in November 1970. The photometric data are supplemented by spectral scans in the wavelength intervals 3800-1800 A and 2000-1050 A; the latter interval was scanned at 10 A resolution once during every OAO-2 orbit, i.e., about 100 minutes. Anomalous features, such as asymmetries and short and long term variations, are present in the light curves. A tentative discussion of solutions of the light curves is given
Non-perturbative solutions of the SD equation for an Abelian gauge field theory
In this article we present a mechanism in which we find new non-perturbative
solutions of quantum electrodynamics in four dimensions. Two non-perturbative
solutions are found for approximate Schwinger-Dyson equations. The mass ratio
of the three solutions (one is ordinary solution) is approximately
.Comment: 6 pages, no figur
Mass flow in the interacting binary TX Ursae Majoris
Twenty-two far-ultraviolet and 23 near-ultraviolet high resolution IUE spectra of the interactive Algol-type binary TX Ursae Majoris (B8 V + F-K III-IV) were analyzed in order to determine the nature of the mass flow occurring in this system. Absorption features due to high-temperature ions of Si IV, C IV, and N V are always present. The resonance lines of Al III, Fe II, Mg II and Si IV show strong phase and secular variations indicative of gas streaming and circumstellar/circumbinary material. Radial velocities as high as 500 to 600 km/sec are present. The gas flow is particularly prominent in 1985 between phases 0.7 and 0.0. The system is more active than U Sagittae and as active as U Cephei
Scattered light in the IUE spectra of Epsilon Aurigae
As a result of this work it was found that light scattered from the longer wavelengths constitutes a small but non-negligible, wavelength and time dependent fraction of the measured flux in the far UV. The reality of the UV excess has not been unambigiously ruled out. However, it is noted that there are still uncertainties in the assumed scattering profile. New measurements of the scattering properties of the cross disperser grating are planned in order to verify the results of Mount and Fastie and extend the wavelength coverage into the far wings of the profile. The results of these measurements will no doubt reduce some of these uncertainties. For the present, it is felt that the BCH approach is a significant improvement over the methods heretofore available for the treatment of scattered light in IUE spectra
On ghost condensation, mass generation and Abelian dominance in the Maximal Abelian Gauge
Recent work claimed that the off-diagonal gluons (and ghosts) in pure
Yang-Mills theories, with Maximal Abelian gauge fixing (MAG), attain a
dynamical mass through an off-diagonal ghost condensate. This condensation
takes place due to a quartic ghost interaction, unavoidably present in MAG for
renormalizability purposes. The off-diagonal mass can be seen as evidence for
Abelian dominance. We discuss why ghost condensation of the type discussed in
those works cannot be the reason for the off-diagonal mass and Abelian
dominance, since it results in a tachyonic mass. We also point out what the
full mechanism behind the generation of a real mass might look like.Comment: 7 pages; uses revtex
A Faddeev-Niemi Solution that Does Not Satisfy Gauss' Law
Faddeev and Niemi have proposed a reformulation of SU(2) Yang-Mills theory in
terms of a U(1) gauge theory with 8 off-shell degrees of freedom. We present a
solution to Faddeev and Niemi's formulation which does not solve the SU(2)
Yang-Mills Gauss constraints. This demonstrates that the proposed reformulation
is inequivalent to Yang-Mills, but instead describes Yang-Mills coupled to a
particular choice of external charge.Comment: 10 pages, no figure
Spontaneous Chiral-Symmetry Breaking in Three-Dimensional QED with a Chern--Simons Term
In three-dimensional QED with a Chern--Simons term we study the phase
structure associated with chiral-symmetry breaking in the framework of the
Schwinger--Dyson equation. We give detailed analyses on the analytical and
numerical solutions for the Schwinger--Dyson equation of the fermion
propagator, where the nonlocal gauge-fixing procedure is adopted to avoid
wave-function renormalization for the fermion. In the absence of the
Chern--Simons term, there exists a finite critical number of four-component
fermion flavors, at which a continuous (infinite-order) chiral phase transition
takes place and below which the chiral symmetry is spontaneously broken. In the
presence of the Chern--Simons term, we find that the spontaneous
chiral-symmetry-breaking transition continues to exist, but the type of phase
transition turns into a discontinuous first-order transition. A simple
stability argument is given based on the effective potential, whose stationary
point gives the solution of the Schwinger-Dyson equation.Comment: 34 pages, revtex, with 9 postscriptfigures appended (uuencoded
Monopoles and fractional vortices in chiral superconductors
We discuss two exotic objects, which must be experimentally identified in
chiral superfluids and superconductors. These are (i) the vortex with
fractional quantum number (N=1/2 in chiral superfluids, and N=1/2 and N=1/4 in
chiral superconductors), which plays the part ofthe Alice string in
relativistic theories; and (ii) the hedgehog in the l-field, which is the
counterpart of the Dirac magnetic monopole. These objects of different
dimensions are topologically connected. They form the combined object which is
called nexus in relativistic theories. In chiral superconductors the nexus has
magnetic charge emanating radially from the hedgehog, while the half-quantum
vortices play the part of the Dirac string. Each of them supplies the
fractional magnetic flux to the hedgehog, representing 1/4 of the
"conventional" Dirac string. We discuss the topological interaction of the
superconductor's nexus with the `t Hooft-Polyakov magnetic monopole, which can
exist in GUT. The `t Hooft-Polyakov magnetic monopole and the hedgehog with the
same magnetic charge are topologically confined by a piece of the Abrikosov
vortex. Other properties of half-quantum vortices and monopoles are discussed
as well, including fermion zero modes.Comment: RevTex file, 8 pages, 6 Figures, prepared for Proc. Nat. Ac. Sc. US,
typos corrected, one Figure added (the loop trapping fractional flux in
chiral superconductors
Transverse Ward-Takahashi Identity, Anomaly and Schwinger-Dyson Equation
Based on the path integral formalism, we rederive and extend the transverse
Ward-Takahashi identities (which were first derived by Yasushi Takahashi) for
the vector and the axial vector currents and simultaneously discuss the
possible anomaly for them. Subsequently, we propose a new scheme for writing
down and solving the Schwinger-Dyson equation in which the the transverse
Ward-Takahashi identity together with the usual (longitudinal) Ward-Takahashi
identity are applied to specify the fermion-boson vertex function. Especially,
in two dimensional Abelian gauge theory, we show that this scheme leads to the
exact and closed Schwinger-Dyson equation for the fermion propagator in the
chiral limit (when the bare fermion mass is zero) and that the Schwinger-Dyson
equation can be exactly solved.Comment: 22 pages, latex, no figure
A new approach to axial coupling constants in the QCD sum rule
We derive new QCD sum rules for the axial coupling constants by considering
two-point correlation functions of the axial-vector currents in a one nucleon
state. The QCD sum rules tell us that the axial coupling constants are
expressed by nucleon matrix elements of quark and gluon operators which are
related to the sigma terms and the moments of parton distribution functions.
The results for the iso-vector axial coupling constants and the 8th component
of the SU(3) octet are in good agreement with experiment.Comment: 10 pages, 1 figure include
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