53,763 research outputs found
A Layman's guide to SUSY GUTs
The determination of the most straightforward evidence for the existence of
the Superworld requires a guide for non-experts (especially experimental
physicists) for them to make their own judgement on the value of such
predictions. For this purpose we review the most basic results of Super-Grand
unification in a simple and clear way. We focus the attention on two specific
models and their predictions. These two models represent an example of a direct
comparison between a traditional unified-theory and a string-inspired approach
to the solution of the many open problems of the Standard Model. We emphasize
that viable models must satisfy {\em all} available experimental constraints
and be as simple as theoretically possible. The two well defined supergravity
models, and , can be described in terms of only a few
parameters (five and three respectively) instead of the more than twenty needed
in the MSSM model, \ie, the Minimal Supersymmetric extension of the Standard
Model. A case of special interest is the strict no-scale
supergravity where all predictions depend on only one parameter (plus the
top-quark mass). A general consequence of these analyses is that supersymmetric
particles can be at the verge of discovery, lurking around the corner at
present and near future facilities. This review should help anyone distinguish
between well motivated predictions and predictions based on arbitrary choices
of parameters in undefined models.Comment: 25 pages, Latex, 11 figures (not included), CERN-TH.7077/93,
CTP-TAMU-65/93. A complete ps file (1.31MB) with embedded figures is
available by request from [email protected]
NLO predictions for the growth of at small and comparison with experimental data
We present parametrizations for the proton structure function in the
next to leading order in perturbative QCD. The calculations show that the
dominant term to should grow as x^{-\ls} for small values,
with the exponent \ls being essentially independent of . Comparisons
with the most recent H1 and ZEUS data confirm the value \ls \sim 0.35
obtained previously from fits to low energy data.Comment: 18 page
Enhanced resistance of single-layer graphene to ion bombardment
We report that single-layer graphene on a SiO_2/Si substrate withstands ion bombardment up to ~7
times longer than expected when exposed to focused Ga^+ ion beam. The exposure is performed in
a dual beam scanning electron microscope/focused ion beam system at 30 kV accelerating voltage
and 41 pA current. Ga^+ ion flux is determined by sputtering a known volume of hydrogenated
amorphous carbon film deposited via plasma-enhanced chemical vapor deposition
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