7,755 research outputs found
On the Symmetric Space Sigma-Model Kinematics
The solvable Lie algebra parametrization of the symmetric spaces is
discussed. Based on the solvable Lie algebra gauge two equivalent formulations
of the symmetric space sigma model are studied. Their correspondence is
established by inspecting the normalization conditions and deriving the field
transformation laws.Comment: 17 page
coupling constant in light cone QCD sum rules
We employ the light cone QCD sum rules to calculate coupling
constant by studying the two point correlation function between the vacuum and
the pion state. Our result is consistent with the traditional QCD sum rules
calculations and it is in agreement with the experimental value.Comment: 8 pages, latex, 2 figure
Symmetric space sigma-model dynamics: Current formalism
After explicitly constructing the symmetric space sigma model lagrangian in
terms of the coset scalars of the solvable Lie algebra gauge in the current
formalism we derive the field equations of the theory.Comment: 10 page
g_phi-pion-gamma coupling constant in light cone QCD sum rules
The coupling constant of g_phi-pion-gamma decay is calculated using light
cone QCD sum rules. A comparison of our result with the ones existing in the
literature is presented.Comment: 9 pages, 2 figure
Mechanics of soil erosion from overland flow generated by simulated rainfall
September 1973.Bibliography: pages 53-54
Study of Eclipsing Binary and Multiple Systems in OB Associations II. The Cygnus OB Region: V443 Cyg, V456 Cyg and V2107 Cyg
Three presumably young eclipsing binary systems in the direction of the
Cygnus OB1, OB3 and OB9 associations are studied. Component spectra are
reconstructed and their orbits are determined using light curves and spectra
disentangling techniques. V443 Cyg and V456 Cyg have circular orbits, while the
light curve of V2107\,Cyg imposes a slightly eccentric orbit
(. V443 Cyg harbours F-type stars, and not young early-A stars
as previously suggested in the literature based on photometry solely. It
appears to be situated in the foreground (distance kpc) of the
young stellar populations in Cygnus. V456 Cyg, at a distance of
kpc consists of a slightly metal-weak A--type and an early--F star. The age of
both systems, on or very near to the main sequence, remains uncertain by an
order of magnitude. V2107 Cyg is a more massive system ( and
) at kpc and, also kinematically, a strong
candidate-member of Cyg OB1. The more massive component is slightly evolved and
appears to undergo non-radial -type pulsations. The Doppler signal
of the secondary is barely detectable. A more extensive study is important to
fix masses more precisely, and an asteroseismological study would then become
appropriate. Nevertheless, the position of the primary in the HR-diagram
confines the age already reasonably well to Myr, indicating for Cyg
OB1 a similar extent of star formation history as established for Cyg OB2.Comment: 27 pages, including 9 figures and 6 tables, accepted for publication
in Astronomical Journa
The Absolute Parameters of The Detached Eclipsing Binary V482 Per
We present the results of the spectroscopic, photometric and orbital period
variation analyses of the detached eclipsing binary \astrobj{V482~Per}. We
derived the absolute parameters of the system (M = 1.51 M,
M = 1.29 M, R = 2.39 R, R = 1.45
R, L = 10.15 L, L = 3.01 L) for the
first time in literature, based on an analysis of our own photometric and
spectroscopic observations. We confirm the nature of the variations observed in
the system's orbital period, suggested to be periodic by earlier works. A light
time effect due to a physically bound, star-sized companion (M = 2.14
M) on a highly eccentric (e = 0.83) orbit, seems to be the most
likely cause. We argue that the companion can not be a single star but another
binary instead. We calculated the evolutionary states of the system's
components, and we found that the primary is slightly evolving after the Main
Sequence, while the less massive secondary lies well inside it.Comment: Published in New Astronomy, Vol. 41, p. 42-4
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