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Twisted Spectral Triple for the Standard Model and Spontaneous Breaking of the Grand Symmetry
No full textGrand symmetry models in noncommutative geometry have been introduced to
explain how to generate minimally (i.e. without adding new fermions) an extra
scalar field beyond the standard model, which both stabilizes the electroweak
vacuum and makes the computation of the mass of the Higgs compatible with its
experimental value. In this paper, we use Connes-Moscovici twisted spectral
triples to cure a technical problem of the grand symmetry, that is the
appearance together with the extra scalar field of unbounded vectorial terms.
The twist makes these terms bounded and - thanks to a twisted version of the
first-order condition that we introduce here - also permits to understand the
breaking to the standard model as a dynamical process induced by the spectral
action. This is a spontaneous breaking from a pre-geometric Pati-Salam model to
the almost-commutative geometry of the standard model, with two Higgs-like
fields: scalar and vector
Unification of coupling constants, dimension 6 operators and the spectral action
No full textWe investigate whether inclusion of dimension 6 terms in the Standard Model Lagrangian may cause the unification of the coupling constants at a scale comprised between 10(14) and 10(17) GeV. Particular choice of the dimension 6 couplings is motivated by the spectral action. Given the theoretical and phenomenological constraints, as well as recent data on the Higgs mass, we find that the unification is indeed possible, with a lower unification scale slightly favored
Grand symmetry, spectral action and the Higgs mass
Full text linkIn the context of the spectral action and the noncommutative geometry approach to the standard model, we build a model based on a larger symmetry. With this grand symmetry it is natural to have the scalar field necessary to obtain the Higgs mass in the vicinity of 126 GeV. This larger symmetry mixes gauge and spin degrees of freedom without introducing extra fermions. Requiring the noncommutative space to be an almost commutative geometry (i.e. the product of manifold by a finite dimensional internal space) gives conditions for the breaking of this grand symmetry to the standard model
Higgs mass in noncommutative geometry
No full textIn the noncommutative geometry approach to the standard model, an extra scalar field σ-initially suggested by particle physicist to stabilize the electroweak vacuum-makes the computation of the Higgs mass compatible with the 126 GeV experimental value. We give a brief account on how to generate this field from the Majorana mass of the neutrino, following the principles of noncommutative geometry
Spectral action and gravitational effects at the Planck scale
No full textAbstractWe discuss the possibility to extend the spectral action up to energy close to the Planck scale, taking also into account the gravitational effects given by graviton exchange. Including this contribution in the theory, the coupling constant unification is not compromised but is shifted to the Planck scale rendering all gauge couplings asymptotically free. In the scheme of noncommutative geometry, the gravitational effects change the main standard model coupling constants, leading to a restriction of the free parameters of the theory compatible with the Higgs and top mass prediction. We also discuss consequences for the neutrino mass and the see-saw mechanism
Particle Physics and Symmetries in Noncommutative Geometry
No full textIn the context of the spectral action and the noncommutative geometry approach to the physical fundamental interactions, we extend the standard model of particle physics introducing a model based on a larger symmetry in the attempt to obtain a new scalar field, bringing the Higgs mass in the vicinity of 126~GeV and to cure the instability problem of the electroweak vacuum. We also investigate whether inclusion of dimension six terms in the Standard Model Lagrangian or gravitational contributions may cause the unification of the gauge coupling constants at high energy scale
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of Caffeine on Attention and Motor Performance
No full textCaffeine is the most commonly consumed psychoactive stimulant in the world. Caffeine is often found to enhance vigilance, alertness and performance in sustained attention tasks for extended periods. It has been implicated in the enhancement of certain higher-order cognitive processes, such as those involved in the active monitoring and coordination of behavior. Caffeine influences also performance in real-life motor tasks, such as handwriting, and in simulated-motor tasks, such as driving. Although the positive effects of caffeine are well documented, controversy surrounds the relationship between regular consumption of caffeine and its beneficial effects. © 2012 Nova Science Publishers, Inc. All rights reserved
Influence of Sedentary and Active Behaviors on Insulin Sensitivity and Glucose Uptake
No full textAbstract:
This article summarizes the effects of inactivity and exercise on muscle glucose uptake and insulin sensitivity. An important determinant of insulin sensitivity in humans, the insulin-induced glucose uptake in skeletal muscle, has been found to be markedly enhanced in trained individuals compared with sedentary controls. Available evidence indicates that the enhanced insulin action is not a genuine training effect, but merely a lasting effect of the previous exercise sessions. Insulin sensitivity increases with single and multiple exercise sessions, and this increase is related to age. The effect disappears after few. The exercise-induced reduction in muscle glycogen is an important factor underlying the increased insulin sensitivity in the period after exercise. Adaptations, which might underlie the increased insulin sensitivity in trained individuals, include increases in levels of the glucose transporter protein GLUT-4 and in muscle glycogen synthase activity, a decrease in the serum triglyceride concentration and, possibly, an increase in the muscle capillary network
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