21,572 research outputs found
Detection of Charged MSSM Higgs Bosons at CERN LEP-II and NLC
We study the possibility of detecting the charged Higgs bosons predicted in
the Minimal Supersymmetric Standard Model , with the reactions
, using the
helicity formalism. We analyze the region of parameter space
where could be detected in the limit when
is large. The numerical computation is done for the energie which
is expected to be available at LEP-II ( GeV) and for a possible
Next Linear Collider ( GeV).Comment: Latex file and 5 figure
Multivariate Bayesian semiparametric models for authentication of food and beverages
Food and beverage authentication is the process by which foods or beverages
are verified as complying with its label description, for example, verifying if
the denomination of origin of an olive oil bottle is correct or if the variety
of a certain bottle of wine matches its label description. The common way to
deal with an authentication process is to measure a number of attributes on
samples of food and then use these as input for a classification problem. Our
motivation stems from data consisting of measurements of nine chemical
compounds denominated Anthocyanins, obtained from samples of Chilean red wines
of grape varieties Cabernet Sauvignon, Merlot and Carm\'{e}n\`{e}re. We
consider a model-based approach to authentication through a semiparametric
multivariate hierarchical linear mixed model for the mean responses, and
covariance matrices that are specific to the classification categories.
Specifically, we propose a model of the ANOVA-DDP type, which takes advantage
of the fact that the available covariates are discrete in nature. The results
suggest that the model performs well compared to other parametric alternatives.
This is also corroborated by application to simulated data.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS492 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Threshold voltage and space charge in organic transistors
We investigate rubrene single-crystal field-effect transistors, whose
stability and reproducibility are sufficient to measure systematically the
shift in threshold voltage as a function of channel length and source-drain
voltage. The shift is due to space-charge transferred from the contacts, and
can be modeled quantitatively without free fitting parameters, using Poisson's
equation, and by assuming that the density of states in rubrene is that of a
conventional inorganic semiconductor. Our results demonstrate the consistency,
at the quantitative level, of a variety of recent experiments on rubrene
crystals, and show how the use of FET measurements can enable the determination
of microscopic parameters (e.g., the effective mass of charge carriers).Comment: 4 pages, 4 figure
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