10,683 research outputs found
Gauge-mediated supersymmetry breaking with generalized messenger sector at LHC
We consider the generalized gauge mediated supersymmetry breaking (GMSB)
models with the messenger elds which do not form the complete multiplets of SU(5)
GUT symmetry. Such a situation may happen in the anomalous U(1) GUT scenario
because the mass spectrum of the superheavy particle does not respect SU(5) GUT
symmetry, although the success of the gauge coupling uni cation can be explained.
In this paper, we assume that one pair of the messenger elds gives the dominant
contribution, and the LHC signature for the two possible messengers, X + X and
Q + Q, are examined. We investigate the possibility to measure the deviation from
the usual GUT relation of the gaugino masses which is one of the most important
features of these scenarios.
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Microcomputer system for medium-sized and experimental finite element analysis
The development of a microcomputer system is described. A series of finite element analysis programs are evaluated in terms of their cost effective application within the microcomputer system. It is shown that the system is practically maintenance free and can be sustained by individual laboratories of standard scale in the educational or academic environment
Formulae for partial widths derived from the Lindblad equation
A method for calculating partial widths of auto-ionizing states is proposed.
It combines either a complex absorbing potential or exterior complex scaling
with the Lindblad equation. The corresponding classical rate equations are
reproduced, and the trace conservation inherent in the Lindblad equation
ensures that the partial widths sums up to the total width of the initial
auto-ionizing state
Valence and Na content dependences of superconductivity in NaxCoO2.yH2O
Various samples of sodium cobalt oxyhydrate with relatively large amounts of
Na ions were synthesized by a modified soft-chemical process in which a
NaOH aqueous solution was added in the final step of the procedure. From these
samples, a superconducting phase diagram was determined for a section of a
cobalt valence of +3.48, which was compared with a previously obtained
one of +3.40. The superconductivity was significantly affected by the
isovalent exchanger of Na and HO, rather than by variation of
Co valence, suggesting the presence of multiple kinds of Fermi surface.
Furthermore, the high-field magnetic susceptibility measurements for one sample
up to 30 T indicated an upper critical field much higher than the Pauli limit
supporting the validity of the spin-triplet pairing mechanism.Comment: 4 figures and 1 tabl
Visibility and aerosol measurement by diode-laser random-modulation CW lidar
Examples of diode laser (DL) random-modulation continuous wave (RM-CW) lidar measurements are reported. The ability of the measurement of the visibility, vertical aerosol profile, and the cloud ceiling height is demonstrated. Although the data shown here were all measured at night time, the daytime measurement is, of course, possible. For that purpose, accurate control of the laser frequency to the center frequency of a narrow band filter is required. Now a new system with a frequency control is under construction
Behavior of Li abundances in solar-analog stars II. Evidence of the connection with rotation and stellar activity
We previously attempted to ascertain why the Li I 6708 line-strengths of
Sun-like stars differ so significantly despite the superficial similarities of
stellar parameters. We carried out a comprehensive analysis of 118 solar
analogs and reported that a close connection exists between the Li abundance
A_Li and the line-broadening width (v_r+m; mainly contributed by rotational
effect), which led us to conclude that stellar rotation may be the primary
control of the surface Li content. To examine our claim in more detail, we
study whether the degree of stellar activity exhibits a similar correlation
with the Li abundance, which is expected because of the widely believed close
connection between rotation and activity. We measured the residual flux at the
line center of the strong Ca II 8542 line, r_0(8542), known to be a useful
index of stellar activity, for all sample stars using newly acquired spectra in
this near-IR region. The projected rotational velocity (v_e sin i) was
estimated by subtracting the macroturbulence contribution from v_r+m that we
had already established. A remarkable (positive) correlation was found in the
A_Li versus (vs.) r_0(8542) diagram as well as in both the r_0(8542) vs. v_e
sin i and A_Li vs. v_e sin i diagrams, as had been expected. With the
confirmation of rotation-dependent stellar activity, this clearly shows that
the surface Li abundances of these solar analogs progressively decrease as the
rotation rate decreases. Given this observational evidence, we conclude that
the depletion of surface Li in solar-type stars, probably caused by effective
envelope mixing, operates more efficiently as stellar rotation decelerates. It
may be promising to attribute the low-Li tendency of planet-host G dwarfs to
their different nature in the stellar angular momentum.Comment: 12 pages, 9 figures; accepted for publication in Astron. Astrophys
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