4,211 research outputs found

    Charge breaking bounds in the Zee model

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    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

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    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

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    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

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    [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

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    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

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    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

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    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

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    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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