39,034 research outputs found
Efficient reconstruction of CMSSM parameters from LHC data - A case study
We present an efficient method of reconstructing the parameters of the
Constrained MSSM from assumed future LHC data, applied both on their own right
and in combination with the cosmological determination of the relic dark matter
abundance. Focusing on the ATLAS SU3 benchmark point, we demonstrate that our
simple Gaussian approximation can recover the values of its parameters
remarkably well. We examine two popular non-informative priors and obtain very
similar results, although when we use an informative, naturalness-motivated
prior, we find some sizeable differences. We show that a further strong
improvement in reconstructing the SU3 parameters can by achieved by applying
additional information about the relic abundance at the level of WMAP accuracy,
although the expected data from Planck will have only a very limited additional
impact. Further external data may be required to break some remaining
degeneracies. We argue that the method presented here is applicable to a wide
class of low-energy effective supersymmetric models, as it does not require to
deal with purely experimental issues, eg, detector performance, and has the
additional advantages of computational efficiency. Furthermore, our approach
allows one to distinguish the effect of the model's internal structure and of
the external data on the final parameters constraints.Comment: 23 pages, 10 figures - moderate revision: includes naturalness prior.
Matches published versio
The impact of priors and observables on parameter inferences in the Constrained MSSM
We use a newly released version of the SuperBayeS code to analyze the impact
of the choice of priors and the influence of various constraints on the
statistical conclusions for the preferred values of the parameters of the
Constrained MSSM. We assess the effect in a Bayesian framework and compare it
with an alternative likelihood-based measure of a profile likelihood. We employ
a new scanning algorithm (MultiNest) which increases the computational
efficiency by a factor ~200 with respect to previously used techniques. We
demonstrate that the currently available data are not yet sufficiently
constraining to allow one to determine the preferred values of CMSSM parameters
in a way that is completely independent of the choice of priors and statistical
measures. While b->s gamma generally favors large m_0, this is in some contrast
with the preference for low values of m_0 and m_1/2 that is almost entirely a
consequence of a combination of prior effects and a single constraint coming
from the anomalous magnetic moment of the muon, which remains somewhat
controversial. Using an information-theoretical measure, we find that the
cosmological dark matter abundance determination provides at least 80% of the
total constraining power of all available observables. Despite the remaining
uncertainties, prospects for direct detection in the CMSSM remain excellent,
with the spin-independent neutralino-proton cross section almost guaranteed
above sigma_SI ~ 10^{-10} pb, independently of the choice of priors or
statistics. Likewise, gluino and lightest Higgs discovery at the LHC remain
highly encouraging. While in this work we have used the CMSSM as particle
physics model, our formalism and scanning technique can be readily applied to a
wider class of models with several free parameters.Comment: Minor changes, extended discussion of profile likelihood. Matches
JHEP accepted version. SuperBayeS code with MultiNest algorithm available at
http://www.superbayes.or
Are the hosts of VLBI selected radio-AGN different to those of radio-loud AGN?
Recent studies have found that radio-AGN selected by radio-loudness show
little difference in terms of their host galaxy properties when compared to
non-AGN galaxies of similar stellar mass and redshift. Using new 1.4~GHz VLBI
observations of the COSMOS field we find that approximately 49\% of
high-mass (M 10 M), high luminosity (L
10 W~Hz) radio-AGN possess a VLBI detected counterpart. These
objects show no discernible bias towards specific stellar masses, redshifts or
host properties other than what is shown by the radio-AGN population in
general. Radio-AGN that are detected in VLBI observations are not special, but
form a representative sample of the radio-loud AGN population.Comment: 6 pages, 4 figures, lette
Minimally non-local nucleon-nucleon potentials with chiral two-pion exchange including 's
We construct a coordinate-space chiral potential, including -isobar
intermediate states in its two-pion-exchange component. The contact
interactions entering at next-to-leading and next-to-next-to-next-to-leading
orders ( and , respectively, denoting generically the low
momentum scale) are rearranged by Fierz transformations to yield terms at most
quadratic in the relative momentum operator of the two nucleons. The low-energy
constants multiplying these contact interactions are fitted to the 2013 Granada
database, consisting of 2309 and 2982 data (including, respectively,
148 and 218 normalizations) in the laboratory-energy range 0--300 MeV. For the
total 5291 and data in this range, we obtain a /datum of
roughly 1.3 for a set of three models characterized by long- and short-range
cutoffs, and respectively, ranging from fm down to fm. The long-range
(short-range) cutoff regularizes the one- and two-pion exchange (contact) part
of the potential.Comment: 32 pages, 19 figures, accepted for publication as a Regular Article
in Physical Review
Predicción de la frescura del aceite de oliva virgen extra durante el almacenamiento mediante espectroscopía de fluorescencia
Virgin olive oil quality relates to flavor and unique health benefits. Some of these properties are
at the most desirable level when the oil is just extracted, since it is not a product that improves with age. On the
contrary, the concentrations of many compounds change during its shelf-life. These changes reveal the aging of
the oil but do not necessarily mean decay in sensory properties, so in some cases an aged oil from healthy olives
may be better qualified than a fresh one from olives affected by fermentation. The aim of this work is to analyze
different methodologies proposed for assessing the quality of virgin olive oil with implications in freshness and
aging of the oil, and to highlight the possibilities of rapid spectrofluorimetric techniques for assessing oil freshness by checking the evolution of pigments during storage. The observed change in the selected spectral features
and mathematical modelling over time was compared with the accepted model for predicting the amount of
pyropheophytin a, which is based on isokinetic studies. The best regression was obtained for 655 nm (adjustedR2
= 0.91) wavelength, which matches the distinctive band of pigments. The two mathematical models described
in this study highlight the usefulness of pigments in the prediction of the shelf-life of extra virgin olive oil.La calidad del aceite de oliva virgen está relacionada con su flavor y sus beneficios
únicos para la salud. Algunas de estas propiedades se encuentran en el nivel más deseable cuando el aceite está
recién extraído, ya que no es un producto que mejore con el tiempo. Por el contrario, las concentraciones de
muchos compuestos cambian a lo largo de la vida útil. Estos cambios revelan el envejecimiento del aceite, pero
no implican necesariamente la alteración de las propiedades sensoriales, por lo que en algunos casos un aceite
envejecido procedente de aceitunas sanas puede presentar mejor calidad que uno fresco procedente de aceitunas
afectadas por procesos de fermentación. El objetivo de este trabajo es estudiar diferentes metodologías propuestas para evaluar la calidad del aceite de oliva virgen con implicaciones en la frescura y el envejecimiento del
aceite, destacando las posibilidades de las rápidas técnicas espectrofluorométricas para evaluar la frescura del
aceite verificando la evolución de los pigmentos durante el almacenamiento. El cambio observado en las características espectrales seleccionadas y su modelado matemático a lo largo del tiempo se comparó con el modelo
aceptado para predecir la cantidad de pirofeofitina a, que se basa en estudios isocinéticos. Los dos modelos
matemáticos descritos en este estudio pusieron de manifiesto la utilidad de los pigmentos en la predicción de la
vida útil del aceite de oliva virgen extra. La mejor regresión se obtuvo para 655 nm (R2
-ajustado = 0,91), longitud de onda que coincide con la banda distintiva de pigmentos.Secretaría de Estado de Investigación, Desarrollo e Innovación de España-AGL2015-69320-
Predicción de la frescura del aceite de oliva virgen extra durante el almacenamiento mediante espectroscopía de fluorescencia
Virgin olive oil quality relates to flavor and unique health benefits. Some of these properties are
at the most desirable level when the oil is just extracted, since it is not a product that improves with age. On the
contrary, the concentrations of many compounds change during its shelf-life. These changes reveal the aging of
the oil but do not necessarily mean decay in sensory properties, so in some cases an aged oil from healthy olives
may be better qualified than a fresh one from olives affected by fermentation. The aim of this work is to analyze
different methodologies proposed for assessing the quality of virgin olive oil with implications in freshness and
aging of the oil, and to highlight the possibilities of rapid spectrofluorimetric techniques for assessing oil freshness by checking the evolution of pigments during storage. The observed change in the selected spectral features
and mathematical modelling over time was compared with the accepted model for predicting the amount of
pyropheophytin a, which is based on isokinetic studies. The best regression was obtained for 655 nm (adjustedR2
= 0.91) wavelength, which matches the distinctive band of pigments. The two mathematical models described
in this study highlight the usefulness of pigments in the prediction of the shelf-life of extra virgin olive oil.La calidad del aceite de oliva virgen está relacionada con su flavor y sus beneficios
únicos para la salud. Algunas de estas propiedades se encuentran en el nivel más deseable cuando el aceite está
recién extraído, ya que no es un producto que mejore con el tiempo. Por el contrario, las concentraciones de
muchos compuestos cambian a lo largo de la vida útil. Estos cambios revelan el envejecimiento del aceite, pero
no implican necesariamente la alteración de las propiedades sensoriales, por lo que en algunos casos un aceite
envejecido procedente de aceitunas sanas puede presentar mejor calidad que uno fresco procedente de aceitunas
afectadas por procesos de fermentación. El objetivo de este trabajo es estudiar diferentes metodologías propuestas para evaluar la calidad del aceite de oliva virgen con implicaciones en la frescura y el envejecimiento del
aceite, destacando las posibilidades de las rápidas técnicas espectrofluorométricas para evaluar la frescura del
aceite verificando la evolución de los pigmentos durante el almacenamiento. El cambio observado en las características espectrales seleccionadas y su modelado matemático a lo largo del tiempo se comparó con el modelo
aceptado para predecir la cantidad de pirofeofitina a, que se basa en estudios isocinéticos. Los dos modelos
matemáticos descritos en este estudio pusieron de manifiesto la utilidad de los pigmentos en la predicción de la
vida útil del aceite de oliva virgen extra. La mejor regresión se obtuvo para 655 nm (R2
-ajustado = 0,91), longitud de onda que coincide con la banda distintiva de pigmentos.Secretaría de Estado de Investigación, Desarrollo e Innovación de España-AGL2015-69320-
Multiscale velocity correlation in turbulence: experiments, numerical simulations, synthetic signals
Multiscale correlation functions in high Reynolds number experimental
turbulence, numerical simulations and synthetic signals are investigated.
Fusion Rules predictions as they arise from multiplicative, almost
uncorrelated, random processes for the energy cascade are tested. Leading and
sub-leading contribution, in the inertial range, can be explained as arising
from a multiplicative random process for the energy transfer mechanisms. Two
different predictions for correlations involving dissipative observable are
also briefly discussed
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