18,074 research outputs found
LHC Signature of the Minimal SUGRA Model with a Large Soft Scalar Mass
Thanks to the focus point phenomenon, it is quite {\it natural} for the
minimal SUGRA model to have a large soft scalar mass m_0 > 1 TeV. A distinctive
feature of this model is an inverted hierarchy, where the lighter stop has a
significantly smaller mass than the other squarks and sleptons. Consequently,
the gluino is predicted to decay dominantly via stop exchange into a channel
containing 2b and 2W along with the LSP. We exploit this feature to construct a
robust signature for this model at the LHC in leptonic channels with 3-4 b-tags
and a large missing-E_T.Comment: Small clarifications added. Final version to appear in Phys. Lett.
Effects of SO(10) D-Terms on SUSY Signals at the Tevatron
We study signals for the production of superparticles at the Tevatron in
supergravity scenarios based on the Grand Unified group SO(10). The breaking of
this group introduces extra contributions to the masses of all scalars,
described by a single new parameter. We find that varying this parameter can
considerably change the size of various expected signals studied in the
literature, with different numbers of jets and/or charged leptons in the final
state. The ratios of these signal can thus serve as a diagnostic to detect or
constrain deviations from the much--studied scenario where all scalar masses
are universal at the GUT scale. Moreover, under favorable circumstances some of
these signals, and/or new signals involving hard jets, should be observable
at the next run of the Tevatron collider even if the average scalar mass lies
well above the gluino mass.Comment: 17 pages, LaTeX including 3 postscript figures, uses equation.st
On the production mechanism of radio-pulses from large extensive air showers
None of the theories put forward so far to explain the radio emission from cosmic ray showers, has been successful in giving a satisfactory explanation for all the experimental data obtained from various laboratories over the globe. It is apprehended that emission mechanism at low and high frequencies may be quite different. This calls for new theoretical look into the phenomenon. Theoretical as well as the experimental results indicate that the frequency spectrum is rather flat in the frequency range (40 to 60 MHz. Above 80 MHz, the radio emission can be explained with the help of geomagnetic mechanism. But at very low frequency ( 10 MHz), mechanisms other than geomagnetic are involved
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