7,502 research outputs found
Spectrophotometry of comet Kohoutek (1973f) during pre-perihelion period
Scans of the head of comet Kohoutek obtained during the pre-perihelion period with a photoelectric spectrum scanner are discussed. The mean relative flux distributions and the continuum energy distribution of the head of comet Kohoutek are given and normalized to 479 nm. The emission features of CN, C3, Ch, and the principal Swan band sequences of C2 and Na are identified and discussed. The adopted monochromatic values relative to 479 nm are given and plotted along with the energy distribution of the sun
Neutrino Anomalies in an Extended Zee Model
We discuss an extended model which naturally leads to mass
scales and mixing angles relevant for understanding both the solar and
atmospheric neutrino anomalies. No right-handed neutrinos are introduced in the
model.The model uses a softly broken symmetry. Neutrino
masses arise only at the loop level. The one-loop neutrino masses which arise
as in the Zee model solve the atmospheric neutrino anomaly while breaking of
generates at two-loop order a mass splitting needed for
the vacuum solution of the solar neutrino problem. A somewhat different model
is possible which accommodates the large-angle MSW resolution of the solar
neutrino problem.Comment: 11 pages including 2 figures; a reference added and text changed
accordingl
Enhanced self-field critical current density of nano-composite YBa(2)Cu(3)O(7) thin films grown by pulsed-laser deposition
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ EPLA, 2008.Enhanced self-field critical current density Jc of novel, high-temperature superconducting thin films is reported. Layers are deposited on (001) MgO substrates by laser ablation of YBa2Cu3O7−δ(Y-123) ceramics containing Y2Ba4CuMOx (M-2411, M=Ag, Nb, Ru, Zr) nano-particles. The Jc of films depends on the secondary-phase content of the ceramic targets, which was varied between 0 and 15 mol%. Composite layers (2 mol% of Ag-2411 and Nb-2411) exhibit Jc values at 77 K of up to 5.1 MA/cm2, which is 3 to 4 times higher than those observed in films deposited from phase pure Y-123 ceramics. Nb-2411 grows epitaxially in the composite layers and the estimated crystallite size is ~10 nm.The Austrian Science Fund, the Austrian Federal Ministry of Economics and Labour, the European Science Foundation and the Higher Education Commission of Pakistan
SUSY breaking based on Abelian gaugino kinetic term mixings
We present a SUSY breaking scenario based on Abelian gaugino kinetic term
mixings between hidden and observable sectors. If an extra U(1) gaugino in the
observable sector obtains a large mass through this mixing effect based on SUSY
breaking in the hidden sector, soft SUSY breaking parameters in the MSSM may be
affected by radiative effects due to this gaugino mass. New phenomenological
aspects are discussed in such a SUSY breaking scenario.Comment: latex, 12pages, 2figures, published versio
Recent direct measurement of the Top quark mass and quasi-infrared fixed point
We note that the recent direct measurement of the top quark mass at by D0 collaboration severely constrains the
theoretically attractive infra-red fixed point scenario of the top quark Yukawa
coupling in supersymmetric GUTs. For one-step unified models the above
mentioned measurement bounds the arbitrary but experimentally determinable
parameter to the range . Further
crunch on the top quark mass may determine even more accurately
within the fixed point scenario. On the other hand an experimental value of
will rule out the fixed point scenario bounding
to 0.022 from above.Comment: 7 pages, Latex with epsf style, 1 figure, captions.st
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