1,128 research outputs found
Nonextensive Quantum H-Theorem
A proof of the quantum -theorem taking into account nonextensive effects
on the quantum entropy is shown. The positiveness of the time variation
of combined with a duality transformation implies that the nonextensive
parameter lies in the interval [0,2]. It is also shown that the equilibrium
states are described by quantum -power law extensions of the Fermi-Dirac and
Bose-Einstein distributions. Such results reduce to the standard ones in the
extensive limit, thereby showing that the nonextensive entropic framework can
be harmonized with the quantum distributions contained in the quantum
statistics theory.Comment: 5 pages, LaTe
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]
Planck Scale Physics and the Testability of SU(5) Supergravity GUT
GUT scale threshold corrections in minimal SU(5) supergravity grand
unification are discussed. It is shown that predictions may be made despite
uncertainties associated with the high energy scale. A bound relating the
strong coupling constant to the mass scales associated with proton decay and
supersymmetry is derived, and a sensitive probe of the underlying theory is
outlined. In particular, low energy measurements can in principle determine the
presence of Planck scale () terms.Comment: 12 pages, REVTeX, 2 figures included in an uuencoded Z-compressed
PostScript file. Ready to print PostScript version (with figures) may be
picked up at ftp://phys.tamu.edu/urano/planck/paper_prep.p
Predictions for Constrained Minimal Supersymmetry with Bottom-Tau Mass Unification
We examine the Constrained Minimal Supersymmetric Standard Model (CMSSM) with
an additional requirement of strict b - tau unification in the region of small
tan(beta). We find that the parameter space becomes completely limited below
about 1 TeV by physical constraints alone, without a fine-tuning constraint. We
study the resulting phenomenological consequences, and point out several ways
of falsifying the adopted b - tau unification assumption. We also comment on
the effect of a constraint from the non-observation of proton decay.Comment: Michigan preprint UM-TH-94-03, LaTeX, 18 pages with inline figures
(figures included in uuencoded file). Complete PS file also available by
anonymous FTP to williams.physics.lsa.umich.edu in
/pub/preprints/UM-TH-94-03.ps.Z or by e-mailing reques
Precision Electroweak Tests of the Minimal and Flipped SU(5) Supergravity Models
We explore the one-loop electroweak radiative corrections in the minimal
and the no-scale flipped supergravity models via explicit
calculation of vacuum polarization contributions to the
parameters. Experimentally, are obtained from a global fit
to the LEP observables, and measurements. We include -dependent
effects which have been neglected in most previous ``model-independent"
analyses of this type. These effects induce a large systematic negative shift
on for light chargino masses (m_{\chi^\pm_1}\lsim70\GeV).
In agreement with previous general arguments, we find that for increasingly
large sparticle masses, the heavy sector of both models rapidly decouples, \ie,
the values for quickly asymptote to the Standard Model
values with a {\it light} Higgs (m_{H_{SM}}\sim100\GeV). Specifically, at
present the CL upper limit on the top-quark mass is m_t\lsim175\GeV in
the no-scale flipped supergravity model. These bounds can be
strengthened for increasing chargino masses in the 50-100\GeV interval. In
particular, for m_t\gsim160\GeV, the Tevatron may be able to probe through
gluino() and squark() production up to m_{\tilde g}\approx
m_{\tilde q}\approx250\GeV, exploring at least half of the parameter space in
this model.Comment: 15 pages,(6 ps figures available upon request), TeX(harvmac),
CTP-TAMU-19/93, ACT-07/9
Variabilidade genética entre acessos de pinhão-manso na fase juvenil.
O pinhão-manso está entre as oleaginosas que podem ser cultivadas para aumentar a produção de biodiesel. Este trabalho teve como objetivo estudar a variabilidade genética entre acessos de pinhão-manso do Banco Ativo de Germoplasma da Universidade Federal de Mato Grosso do Sul, com base em características tomadas na fase juvenil das plantas. Foram avaliados dez acessos de pinhão-manso, oriundos de diferentes locais, tomando-se para avaliação as características: altura de plantas, altura de inserção da primeira folha, diâmetro do caule e número de folhas. A análise estatística foi baseada em modelos mistos do tipo REML/BLUP. Os valores genotípicos preditos dos acessos foram utilizados na realização da análise multivariada para cômputo de distâncias genéticas entre procedências e agrupamento pelo método de Tocher. Os resultados indicaram a presença de considerável variabilidade entre os dez acessos. A herdabilidade de plantas individuais no sentido amplo foi baixa, porém para a herdabilidade da média de acesso foram obtidos altos coeficientes: 56% para altura de plantas, 82% para altura da primeira folha, 76% para diâmetro de caule e 89% para número de folhas. Tais valores indicam a possibilidade de grande precisão na seleção entre populações. No estudo da divergência, os acessos avaliados foram separados em dois grupos distintos: o primeiro grupo com sete acessos similares geneticamente, e o segundo com três acessos
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