11,207 research outputs found
Preliminary Skylab MSS channel evaluation
The author has identified the following significant results. A set of 18 channels which were considered of usable quality were identified. These were channels 1-14, 17, 19-21. Channels 15, 16, 18, and 22 were dropped out because they were of poor quality; channels 7 and 11 were dropped to limit the total channel number to 16. From these 16 channels, a total of 22 signatures were obtained. Eight were developed from uniform blocks of the UMAP, and 14 from use of the DCLUS program. These signatures fell into six basic categories and classified more than 90% of the five scenes mapped: agriculture land (6 signatures); forest aland (4); water (2); open nonagriculture land (2); urban (6); and disturbed land (2)
Enhancement of W+/- H-/+ Production at Hadron Colliders in the Two Higgs Doublet Model
We discuss the associated W+/- H-/+ production at the CERN Large Hadron
Collider. The dependence of the hadronic cross section on the Higgs sector
parameters is investigated in detail in the framework of the general Two Higgs
Doublet Model (THDM). We study the possible enhancement of the THDM prediction
for the cross section compared to the prediction of the Minimal Supersymmetric
Standard Model (MSSM). We find regions in the THDM parameter space where the
THDM prediction can exceed the one of the MSSM by two orders of magnitude.
These regions of large cross section are in agreement with theoretical bounds
on the model, derived from the requirement of vacuum stability and perturbative
unitarity, and are not excluded by experimental constraints.Comment: 19 pages, 5 figure
Ruling out a higher spin field solution to the cosmological constant problem
We consider the modification of Newton's gravity law in Dolgov's higher spin
models designed to compensate the cosmological constant. We find that the
effective Planck mass is unacceptably large in these models. We also point out
that the properties of gravitational waves are entirely different in these
models as compared to general relativity.Comment: 7 pages, LaTe
Supersymmetric particle mass measurement with the boost-corrected contransverse mass
A modification to the contransverse mass (MCT) technique for measuring the
masses of pair-produced semi-invisibly decaying heavy particles is proposed in
which MCT is corrected for non-zero boosts of the centre-of-momentum (CoM)
frame of the heavy states in the laboratory transverse plane. Lack of knowledge
of the mass of the CoM frame prevents exact correction for this boost, however
it is shown that a conservative correction can nevertheless be derived which
always generates an MCT value which is less than or equal to the true value of
MCT in the CoM frame. The new technique is demonstrated with case studies of
mass measurement with fully leptonic ttbar events and with SUSY events
possessing a similar final state.Comment: 33 pages, 33 .eps figures, JHEP3 styl
Vector-meson contributions do not explain the rate and spectrum in K_L -> pi0 gamma gamma
We analyze the recent NA48 data for the reaction K_L -> pi0 gamma gamma with
and without the assumption of vector meson dominance (VMD). We find that the
data is well described by a three-parameter expression inspired by O(p^6)
chiral perturbation theory. We also find that it is impossible to fit the shape
of the decay distribution and the overall rate simultaneously if one imposes
the VMD constraints on the three parameters. We comment on the different fits
and their implications for the CP-conserving component of the decay K_L -> pi0
e+ e-.Comment: Version accepted for publication on Phys. Rev. D. 19 pages, LaTeX, 8
figures, uses epsf.st
The swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory
BeppoSAX observed the low-luminous Seyfert 1 Galaxy NGC4051 in a ultra-dim
X-ray state. The 2-10 keV flux (1.26 x 10^{-12} erg/cm^2/s) was about 20 times
fainter than its historical average value, and remained steady along the whole
observation (~2.3 days). The observed flat spectrum (\Gamma ~ 0.8) and intense
iron line (EW ~600 eV) are best explained assuming that the active nucleus has
switched off, leaving only a residual reflection component visible.Comment: 5 pages, Latex, 3 Postscript figures, accepted for publication in
MNRA
Flavor Alignment Solutions to the Strong CP Problem in Supersymmetry
An approach to solving the Strong CP Problem in supersymmetric theories is
discussed which uses abelian family symmetries to align the mass matrices of
the quarks and squarks. In this way both the Strong CP Problem and the
characteristic flavor and CP problems of supersymmetry can be solved in a
single way.Comment: 13 pages, LaTe
Squark and slepton masses as probes of supersymmetric SO(10) unification
We carry out an analysis of the non-universal supersymmetry breaking scalar
masses arising in SO(10) supersymmetric unification. By considering patterns of
squark and slepton masses, we derive a set of sum rules for the sfermion masses
which are independent of the manner in which SO(10) breaks to the Standard
Model gauge group via its SU(5) subgroups. The phenomenology arising from such
non-universality is unaffected by the symmetry breaking pattern, so long as the
breaking occurs via any of the SU(5) subgroups of the SO(10) group.Comment: 15 pages using RevTe
Sqrt{shat}_{min} resurrected
We discuss the use of the variable sqrt{shat}_{min}, which has been proposed
in order to measure the hard scale of a multi parton final state event using
inclusive quantities only, on a SUSY data sample for a 14 TeV LHC. In its
original version, where this variable was proposed on calorimeter level, the
direct correlation to the hard scattering scale does not survive when effects
from soft physics are taken into account. We here show that when using
reconstructed objects instead of calorimeter energy and momenta as input, we
manage to actually recover this correlation for the parameter point considered
here. We furthermore discuss the effect of including W + jets and t tbar+jets
background in our analysis and the use of sqrt{shat}_{min} for the suppression
of SM induced background in new physics searches.Comment: 23 pages, 9 figures; v2: 1 figure, several subsections and references
as well as new author affiliation added. Corresponds to published versio
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