23,035 research outputs found
Exact Renormalization of Massless QED2
We perform the exact renormalization of two-dimensional massless gauge
theories. Using these exact results we discuss the cluster property and
confinement in both the anomalous and chiral Schwinger models.Comment: 14 pages, no figures, introduction and conclusions modifie
Statistical emulation of a tsunami model for sensitivity analysis and uncertainty quantification
Due to the catastrophic consequences of tsunamis, early warnings need to be
issued quickly in order to mitigate the hazard. Additionally, there is a need
to represent the uncertainty in the predictions of tsunami characteristics
corresponding to the uncertain trigger features (e.g. either position, shape
and speed of a landslide, or sea floor deformation associated with an
earthquake). Unfortunately, computer models are expensive to run. This leads to
significant delays in predictions and makes the uncertainty quantification
impractical. Statistical emulators run almost instantaneously and may represent
well the outputs of the computer model. In this paper, we use the Outer Product
Emulator to build a fast statistical surrogate of a landslide-generated tsunami
computer model. This Bayesian framework enables us to build the emulator by
combining prior knowledge of the computer model properties with a few carefully
chosen model evaluations. The good performance of the emulator is validated
using the Leave-One-Out method
Upper limit on mh in the MSSM and M-SUGRA vs. prospective reach of LEP
The upper limit on the lightest CP-even Higgs boson mass, mh, is analyzed
within the MSSM as a function of tan(beta) for fixed mtop and Msusy. The impact
of recent diagrammatic two-loop results on this limit is investigated. We
compare the MSSM theoretical upper bound on mh with the lower bound obtained
from experimental searches at LEP. We estimate that with the LEP data taken
until the end of 1999, the region mh < 108.2 GeV can be excluded at the 95%
confidence level. This corresponds to an excluded region 0.6 <= tan(beta) <=
1.9 within the MSSM for mtop = 174.3 GeV and Msusy <= 1 TeV. The final
exclusion sensitivity after the end of LEP, in the year 2000, is also briefly
discussed. Finally, we determine the upper limit on mh within the Minimal
Supergravity (M-SUGRA) scenario up to the two-loop level, consistent with
radiative electroweak symmetry breaking. We find an upper bound of mh \approx
127 GeV for mtop = 174.3 GeV in this scenario, which is slightly below the
bound in the unconstrained MSSM.Comment: 10 pages, 3 figure
Regularity at infinity of real mappings and a Morse-Sard theorem
We prove a new Morse-Sard type theorem for the asymptotic critical values of
semi-algebraic mappings and a new fibration theorem at infinity for
mappings. We show the equivalence of three different types of regularity
conditions which have been used in the literature in order to control the
asymptotic behaviour of mappings. The central role of our picture is played by
the -regularity and its bridge toward the -regularity which implies
topological triviality at infinity
Evading the Few TeV Perturbative Limit in 3-3-1 Models
Some versions of the electroweak SU(3)_L\otimesU(1)_X models cannot be
treated within perturbation theory at energies of few TeV. An extended version
for these models is proposed which is perturbative even at TeV scale posing no
threatening inconsistency for test at future colliders. The extension presented
here needs the addition of three octets of vector leptons, which leave three
new leptonic isotriplets in the SU(2)_L\otimesU(1)_Y subgroup. With this
representation content the running of the electroweak mixing angle, , is such that decreases with the increase of the
energy scale , when only the light states of the Standard Model group are
considered. The neutral exotic gauge boson marks then a new symmetry
frontier.Comment: 15 pages, 2 figures, minor correction
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