1,828 research outputs found

    Longitudinal Polarization in KLμ+μK_L \to \mu^+ \mu^- in MSSM with large tanβtan\beta

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    A complete experiment on decay KLl+lK_L \to l^+ l^- will not only consist of measurement of the decay rates but also lepton polarization etc. These additional observations will yield tests of CP invariance in these decays. In KLK_L and KSK_S decays, the e mode is slower than the μ\mu mode by roughly (me/mμ)2(m_e/m_\mu)^2 \cite{sehgal1}. As well discussed in literature \cite{herczeg} the Standard Model contribution to the lepton polarization is of order 2×1032 \times \sim 10^{-3}. We show that in MSSM with large \tanbeta and light higgs masses (2MW\sim 2 M_W), the longitudinal lepton polarization in KLμ+μK_L \to \mu^+ \mu^- can be enhanced to a higher value, of about 10210^{-2}.Comment: version appeared in Physics Letters B, minor correction

    CP--Violating Invariants in Supersymmetry

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    I study the weak basis CP-violating invariants in supersymmetric models, in particular those which cannot be expressed in terms of the Jarlskog--type invariants, and find basis--independent conditions for CP conservation. With an example of the K-anti-K mixing, I clarify what are the combinations of supersymmetric parameters which are constrained by experiment.Comment: matches the PRD versio

    Supernova Neutrino Oscillations

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    Observing a high-statistics neutrino signal from a galactic supernova (SN) would allow one to test the standard delayed explosion scenario and may allow one to distinguish between the normal and inverted neutrino mass ordering due to the effects of flavor oscillations in the SN envelope. One may even observe a signature of SN shock-wave propagation in the detailed time-evolution of the neutrino spectra. A clear identification of flavor oscillation effects in a water Cherenkov detector probably requires a megatonne-class experiment.Comment: Proc. 129 Nobel Symposium "Neutrino Physics", 19-24 Aug 2004, Swede

    Impact of a Web-Based Exercise and Nutritional Education Intervention in Patients Who Are Obese With Hypertension: Randomized Wait-List Controlled Trial

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    Background: Internet-based interventions are a promising strategy for promoting healthy lifestyle behaviors. These have a tremendous potential for delivering electronic health interventions in scalable and cost-effective ways. There is strong evidence that the use of these programs can lead to weight loss and can lower patients’ average blood pressure (BP) levels. So far, few studies have investigated the effects of internet-based programs on patients who are obese with hypertension (HTN). Objective: The aim of this study is to investigate the short- and long-term efficacy, in terms of body composition and BP parameters, of a self-administered internet-based intervention involving different modules and learning techniques aimed at promoting lifestyle changes (both physical activity and healthy eating) in patients who are obese with HTN. Methods: A randomized wait-list controlled trial design was used. We recruited 105 adults with HTN who were overweight or obese and randomly assigned them to either a 3-month internet-based intervention group (n=55) or the wait-list control group (n=50). We assessed BMI (primary outcome), body fat mass (BFM), systolic (S)BP and diastolic (D)BP, blood glucose and insulin levels, physical activity levels, and functional capacity for aerobic exercise at Time 0 (preintervention) and Time 1 (postintervention). All the patients in the wait-list control group subsequently received the intervention, and a secondary within-group analysis, which also included these participants, was conducted at Time 2 (12-month follow-up). Results: A 2-way mixed analysis of covariance showed a significant decrease in BMI, BFM, and blood glucose at 3 months in the internet-based intervention group; the effect size for the BMI and BFM parameters was moderate to large, and there was also a borderline significant trend for DBP and insulin. These results were either maintained or improved upon at Time 2 and showed significant changes for BMI (mean difference −0.4, 95% CI −0.1 to −0.6; P=.005), BFM (mean difference −2.4, 95% CI −1.1 to −3.6; P<.001), DBP (mean difference −1.8, 95% CI −0.2 to −3.3; P=.03), and blood glucose (mean difference −2, 95% CI 0 to −4; P=.04). Conclusions: Implementation of our self-administered internet-based intervention, which involved different learning techniques aimed to promote lifestyle changes, resulted in positive short- and long-term health benefits in patients who are obese with HTN

    D^0-D^0(bar) mixing in the weak-gauged U(4)_L x U(4)_R Chiral Lagrangian Model

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    The D^0-D^0(bar) mixing is analyzed in a weak gauged U(4)_L x U(4)_R chiral lagrangian model where the electroweak interaction is introduced as a gauge theory over the meson degrees of freedom. This model allows a particular realization of the G.I.M. mechanism and then could be useful in the study of processes where G.I.M. suppression is effective. As a test of the model we have also analyzed the K^0-K^0(bar) mixing. We find \Delta m_K in good agreement with the experimental result and we show that the D^0-D^0(bar) mixing is very much suppressed in agreement with previous estimates in the Heavy Quark expansion framework.Comment: 14 pages, 2 figures, Latex, minor changes in the writing, final version to be published in Phys. Lett.

    Bs(d)0Bˉs(d)0B^0_{s(d)} - \bar{B}^0_{s(d)} mixing and new physics effects in a top quark two-Higgs doublet model

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    We calculate the new physics contributions to the neutral Bd0B_d^0 and Bs0B_s^0 meson mass splitting ΔMd\Delta M_d and ΔMs\Delta M_s induced by the box diagrams involving the charged-Higgs bosons in the top quark two-Higgs doublet model (T2HDM). Using the precision data, we obtain the bounds on the parameter space of the T2HDM: (a) for fixed MH=400M_H=400 GeV and δ=[0,60]\delta=[0^\circ,60^\circ], the upper bound on tanβ\tan{\beta} is tanβ30\tan \beta \leq 30 after the inclusion of major theoretical uncertainties; (b) for the case of tanβ20\tan{\beta} \leq 20, a light charged Higgs boson with a mass around 300 GeV is allowed; and (c) the bounds on tanβ\tan{\beta} and MHM_H are strongly correlated: a smaller (larger) tanβ\tan{\beta} means a lighter (heavier) charged Higgs boson.Comment: 11 pages, 2 EPS figures, RevTex, new references adde

    An internet-based treatment for flying phobia using 360° images: A feasibility pilot study

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    Background: More research is needed in the field of Internet-delivered Cognitive Behavioral Treatments (ICBTs) for specific phobia in order to understand which characteristics are important in online exposure scenarios. The aim of the present work was to conduct a feasibility pilot study to explore participants'' opinions, preferences, and acceptability ratings of two types of images (still images vs 360° navigable images) in an ICBT for Flying Phobia (FP). A secondary aim was to test the potential effectiveness of the two active treatment arms compared to a waiting list control group. An exploratory aim was to compare the role of navigable images vs. still images in the level of sense of presence and reality judgment and explore their possible mediation in treatment effectiveness. Methods: Participants were randomly allocated to three conditions: NO-FEAR Airlines with still images (n = 26), NO-FEAR Airlines with still and navigable images (n = 26), and a waiting list group (n = 26). Primary outcome measures were participants'' opinions, preferences, satisfaction, and acceptance regarding the images used in the exposure scenarios. Secondary outcome measures included FP symptomatology outcomes and measures of sense of presence and reality judgment. Results: Participants in the study preferred navigable images over still images before and after treatment (over 84%), and they considered them more effective and logical for the treatment of their problem. However, adherence in the experimental conditions was low (42.3% dropout rate), and more participants withdrew from the group that included navigable images compared to the group that only included still images (14 vs. 8), with no statistical differences in attrition between the two conditions. NO-FEAR Airlines proved to be effective in reducing FP symptomatology compared to the control group, with large between-group effect sizes on all FP measures (ranging from 0.76 to 2.79). No significant mediation effect was found for sense of presence or reality judgment in treatment effectiveness. Discussion: The results of the current study suggest that participants prefer more immersive images in exposure scenarios, providing data that can help to design useful exposure scenarios to treat specific phobias in the future. They also provide evidence supporting the effectiveness of an ICBT for FP. Trial registration: Registered at Clinicaltrials.gov (NCT03900559) on April 9, 2019. Retrospectively registered. © 202

    Small violations of unitarity, the phase in Bs mixing and visible t->cZ decays at the LHC

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    We show that it is possible to accommodate the observed size of the phase in Bs0B^0_s--Bˉs0\bar B^0_s, mixing in the framework of a model with violation of 3×33\times 3 unitarity. This violation is associated to the presence of a new Q=2/3Q=2/3 isosinglet quark TT, which mixes both with tt and cc and has a mass not exceeding 500 GeV. The crucial point is the fact that this framework allows for χarg(VtsVcbVtbVcs)\chi\equiv\arg(-V_{ts}V_{cb}V_{tb}^*V_{cs}^*) of order λ\lambda, to be contrasted with the situation in the Standard Model, where χ\chi is constrained to be of order λ2\lambda^2. We point out that this scenario implies rare top decays tcZt\to cZ at a rate observable at the LHC and Vtb|V_{tb}| significantly different from unity. In this framework, one may also account for the observed size of D0D^0--Dˉ0\bar D^0 mixing without having to invoke long distance contributions. It is also shown that in the present scenario, the observed size of D0D^0--Dˉ0\bar D^0 mixing constrains χarg(VcdVusVcsVud)\chi^\prime\equiv\arg(-V_{cd}V_{us}V_{cs}^*V_{ud}^*) to be of order λ4\lambda^4, which is significantly smaller than what is allowed in generic models with violations of 3×33\times 3 unitarity.Comment: 20 pages. References added. Additional observables considered, updated numerical examples, conclusions unchange

    CP violation versus flavour in supersymmetric theories

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    We show that the quark flavour structure and CP violating phenomena are strongly correlated in supersymmetric theories. For a generic pattern of supersymmetry breaking the two broad categories of Yukawa couplings, democratic and hierarchical textures, have entirely different phenomenological implications. With hierarchical Yukawas, the rephasing invariant phase, arg(V_us V_cb V_cb^* V_cs^*), in the CKM mixing matrix has to be of order unity, while the SUSY CP violating phases are severely constrained by electric dipole moments, giving rise to the so-called SUSY CP problem. With democratic Yukawas, all experimental CP results can be accommodated with small values for the CKM and SUSY CP violating phases (i.e., CP can be considered as an approximate symmetry at the high energy scale). We also show that within this scenario, an entirely real CKM matrix in supersymmetric models is still allowed by the present experimental results.Comment: 16 pages, 6 eps figure
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