4,211 research outputs found
Charge breaking bounds in the Zee model
We study the possibility that charge breaking minima occur in the Zee model.
We reach very different conclusions from those attained in simpler, two Higgs
doublet models, and the reason for this is traced back to the existence of
cubic terms in the potential. A scan of the Zee model's parameter space shows
that CB is restricted to a narrow region of values of the parameters
Effect of Aging on the Lower Limb Kinematics in Karate Practitioners: Comparing Athletes and Their Senseis
With the life expectancy increasing, older adult population has gained the attention of many researchers. Aging is known to lead to a general decline in bodily functions, which affect the quality of life. The aim of this study was to analyze how the aging process affects veteran active karate practitioners, in the kinematic and temporal structure of the frontal kick. Nine black belt karate practitioners over 50 years old and 24 black belt karate practitioners, aged between 20 and 30 years old, all male, performed the frontal kick mae-geri. Results showed that knee is the structure that holds most differences between young and veterans, both for linear and for angular variables during the mae-geri performance. Statistical differences were found in linear velocity for the knee; linear acceleration of the knee, hip, and RASIS; maximum angular velocity for knee and hip; maximum angular acceleration for ankle and hip; and in the range of motion of knee. The temporal variables show differences, between groups, in maximum linear velocity, maximum linear acceleration, and maximum angular acceleration. However, no differences were found between groups for the time before contact in the maximum linear and angular acceleration, which allow us to remark both the effects of the aging process and the effect of training. This study corroborates the ability of older people to achieve benefits from sports practice, achieving higher efficiency than the younger adults in task execution, but using different motor control strategies.info:eu-repo/semantics/publishedVersio
Spontaneous CP Violation in the Next-to-Minimal Supersymmetric Standard Model Revisited
We re-examine spontaneous CP violation at the tree level in the context of
the next-to-minimal supersymmetric standard model (NMSSM) with two Higgs
doublets and a gauge singlet field. We analyse the most general Higgs potential
without a discrete Z_3 symmetry, and derive an upper bound on the mass of the
lightest neutral Higgs boson consistent with present experimental data. We
investigate, in particular, its dependence on the admixture and CP-violating
phase of the gauge singlet field, as well as on tan(beta). To assess the
viability of the spontaneous CP violation scenario, we estimate epsilon_K by
applying the mass insertion approximation. We find that a non-trivial flavour
structure in the soft-breaking A terms is required to account for the observed
CP violation in the neutral kaon sector. Furthermore, combining the
minimisation conditions for spontaneous CP violation with the constraints
coming from K0-K0bar mixing, we find that the upper bound on the lightest
Higgs-boson mass becomes stronger. We also point out that the electric dipole
moments of electron and neutron are a serious challenge for SUSY models with
spontaneous CP violation.Comment: 19 pages, LaTeX2e, 5 figures; matches the published versio
Introduction to data collection for performance analysis and their integration in martial arts training. A biomechanical and motor control perspective
[EN] In order to improve the development of functional, physical, technical and tactical skills of martial arts athletes, coaches look for new ways to collect data
Area Quantization in Quasi-Extreme Black Holes
We consider quasi-extreme Kerr and quasi-extreme Schwarzschild-de Sitter
black holes. From the known analytical expressions obtained for their
quasi-normal modes frequencies, we suggest an area quantization prescription
for those objects.Comment: Final version to appear in Mod. Phys. Lett.
Jarlskog-like invariants for theories with scalars and fermions
Within the framework of theories where both scalars and fermions are present,
we develop a systematic prescription for the construction of CP-violating
quantities that are invariant under basis transformations of those matter
fields. In theories with Spontaneous Symmetry Breaking, the analysis involves
the vevs' transformation properties under a scalar basis change, with a
considerable simplification of the study of CP violation in the scalar sector.
These techniques are then applied in detail to the two Higgs-doublet model with
quarks. It is shown that there are new invariants involving scalar-fermion
interactions, besides those already derived in previous analyses for the
fermion-gauge and scalar-gauge sectors.Comment: 12 pages, Latex, no figure
Flavour Physics and CP Violation in the Standard Model and Beyond
We present the invited lectures given at the Third IDPASC School which took
place in Santiago de Compostela in January 2013. The students attending the
school had very different backgrounds, some of them were doing their Ph.D. in
experimental particle physics, others in theory. As a result, and in order to
make the lectures useful for most of the students, we focused on basic topics
of broad interest, avoiding the more technical aspects of Flavour Physics and
CP Violation. We make a brief review of the Standard Model, paying special
attention to the generation of fermion masses and mixing, as well as to CP
violation. We describe some of the simplest extensions of the SM, emphasising
novel flavour aspects which arise in their framework.Comment: Invited talk at the Third IDPASC School 2013, January 21st - February
2nd 2013, Santiago de Compostela, Galiza, Spain; 36 pages, 8 figures, 2
tables; version with few misprints correcte
Postural Control in Preschool Children with Developmental Coordination Disorder, in Sitting Position During a Functional Task
The developmental coordination disorder is a motor disorder that affects 5 to 6% of children at school-age. The postural control deficit is one of the most prevalent problems affecting 73 to 87% of these children. The present research aims to analyze and compare postural control in probable (p-DCD) and at- risk of developmental coordination disorder children and in typical children in a sitting position during a functional task. p-DCD children were tendentially less recurrent, less periodic, simpler and more regular. These children oscillated more and faster in conditions with visual information; with a visual focus they had more stability and oscillated less and slowler campared to the baseline; without visual information they reduced their oscillations and velocity and become less recurrent, periodic, stable and simpler, possibly freenzing more degrees of freedom in order to respond to absence of external information. p-DCD seem to be more dependent on external stimulus like visual information to auto organize their own balance. The greater the task’s complexity, the lesser and slower their oscillations were but also more recurrent and periodic. Despite oscillating, more and faster in all conditions and being tendentially more recurrent and periodic, in risk children revealed a behaviour pattern similar to typical in both variables. p-DCD, at-risk and typical children reveal the same manner of action without visual information, less and slower oscillations. Most likely, the problem with p-DCD is not in motor control, but on perception-action cycles’ effectivness; and, where stimulation must be focused.info:eu-repo/semantics/publishedVersio
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