263 research outputs found

    CP violating angular asymmetries of b and bbar quarks in e+e- -> t tbar

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    We obtain analytical formulae for the cross section and the angular distributions of the b(bbar) quarks in the process e+e- -> t tbar, with t -> W+ b (tbar -> W- bbar) assuming CP violation in the \gamma t tbar and Z t tbar vertices. We present CP violating asymmetries, which measure separately the real and imaginary parts of the electroweak dipole moment form factors of the top, d^{\gamma}(s) and d^{Z}(s). We give a numerical analysis of these asymmetries within the Minimal Supersymmetric Standard Model with complex parameters. They turn out to be of order <= 10^{-3}.Comment: 22 pages LaTeX with 3x3 figures included; some definitions for polarization asymmetries and some notations are changed and some references adde

    General Flavor Blind MSSM and CP Violation

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    We study the implications on flavor changing neutral current and CP violating processes in the context of supersymmetric theories without a new flavor structure (flavor blind supersymmetry). The low energy parameters are determined by the running of the soft breaking terms from the grand unified scale with SUSY phases consistent with the EDM constraints. We find that the CP asymmetry in b --> s gamma can reach large values potentially measurable at B factories, especially in the low BR(b --> s gamma) region. We perform a fit of the unitarity triangle including all the relevant observables. In this case, no sizeable deviations from the SM expectations are found. Finally we analyze the SUSY contributions to the anomalous magnetic moment of the muon pointing out its impact on the b --> s gamma CP asymmetry and on the SUSY spectrum including chargino and stop masses.Comment: 40 pages, 8 figures, typos corrected, references adde

    General Flavour Blind MSSM and CP Violation

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    We study FCNC and CP violating processes in the MSSM without a new flavour structure (flavour blind MSSM). The low energy parameters are determined by the running of the soft breaking terms from the GUT scale with SUSY phases consistent with the EDM constraints. We find that the CP asymmetry in b -> s gamma can reach large values potentially measurable at B factories, especially in the low BR(b -> s gamma) region. We analyze the SUSY contributions to the anomalous magnetic moment of the muon pointing out its impact on the b -> s gamma CP asymmetry and on the SUSY spectrum.Comment: LaTex, 5 pages, 2 figures, Contribution to the International Europhysics Conference on High Energy Physics (HEP 2001), Budapest, Hungary, 12-18 Jul 200

    Seesaw neutrinos with one right-handed singlet field and a second Higgs doublet

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    We study parameters of an extension of the Standard Model. The neutrino sector is enlarged by one right-handed singlet field, allowing for the seesaw mechanism type-I, and the Higgs sector contains one additional doublet, which contributes to light neutrino masses through one-loop radiative corrections. Employing an approximation for the effective light neutrino mass matrix we express the masses of the light neutrinos analytically, allowing us to parametrize the Yukawa couplings to neutrinos by the experimental measurements on the neutrino sector and only two free parameters. We focus on a CP-conserving Higgs potential for which we present the allowed ranges of the input parameters and a statistical overview over the possible values of the Yukawa couplings.Comment: 35 pages, 9 figures; v2: one figure and references added, some minor changes to the tex

    p-Dimethylaminobenzaldehyde-reactive substances in tail tendon collagen of streptozotocin-diabetic rats: temporal relation to biomechanical properties and advanced glycation endproduct (AGE)-related fluorescence

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    AbstractIn the present work, pepsin digests of tail tendons from streptozotocin-diabetic rats were found to contain material that reacted rapidly at room temperature with p-dimethylaminobenzaldehyde (Ehrlich’s reagent) to give an adduct with an absorbance spectrum characteristic of the Ehrlich chromogen of pyrrolic nature determined in ageing collagens. A significant correlation of the Ehrlich adduct with tendon mechanical strength and collagen fluorescence characteristic of advanced glycation endproducts was observed. Collagen content of the Ehrlich-positive material was found to be significantly elevated in tendons of diabetic rats compared with age-matched healthy controls. The results indicate that the p-dimethylaminobenzaldehyde-reactive pyrrole moieties may contribute to the increased cross-linking of diabetic matrix collagen. Profound inhibitory effect of aminoguanidine was observed, underlining the role of non-enzymatic mechanisms of advanced glycation in pyrrolisation and cross-linking of collagen exposed to hyperglycaemia. It is hypothesised that quantification of the p-dimethylaminobenzaldehyde-reactive material in matrix collagen may provide a tissue measure of integrated hyperglycaemia over prolonged periods of time. Further research is to assess the significance of p-dimethylaminobenzaldehyde-reactive substances in diabetic collagen tissues and to reveal their relationship to enzyme-mediated physiological pyrrolisation of ageing collagens

    Triple product correlations in top squark decays

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    We propose several T-odd asymmetries in the decay chains of the top squarks t~mtχ~k0\tilde t_m \to t \tilde \chi^0_k and tbW+blνt\to bW^+\to bl\nu and χ~k0l±l~nl±lχ~10\tilde\chi^0_k \to l^\pm\tilde l_n^\mp \to l^\pm l^\mp\tilde\chi^0_1, for l=e,μ,τl =e,\mu,\tau. We calculate the asymmetries within the Minimal Supersymmetric Standard Model with complex parameters M1M_1, μ\mu and AtA_t. We give the analytic formulae for the decay distributions. We present numerical results for the asymmetries and estimate the event rates necessary to observe them. The largest T-odd asymmetry can be as large as 40%.Comment: 26 pages, 5 figures; misprints corrected; reference adde

    Reliability of knee joint position sense measurement: a comparison between goniometry and image capture methods

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    Aims: Evaluate the intra-rater and inter-rater reliability of hand-held goniometry compared to image capture (IMC) in the assessment of joint position sense (JPS) in healthy participants. Methodology: Repeated-measures observational study design was undertaken with 36 asymptomatic university students of both genders aged between 18 to 45 years. JPS in the knee was assessed by two assessors over two sessions (one-week interval) using hand-held goniometry and IMC methods. Joint position sense was assessed at four target knee flexion angles. Intra- and inter-rater reliability was assessed with absolute error (AE), relative error (RE) and intra-class correlation coefficient. Findings: Inter-rater reliability for goniometry was poor to substantial (ICC: 0.00 to 0.64) and was poor to moderate (ICC: 0.00 to 0.47) for IMC. Intra-rater reliability for goniometry was poor to moderate (ICC: 0.00 to 0.42) and poor to moderate for IMC (ICC: 0.00 to 0.41). AE for goniometry ranged from 3.2° to 8.6°, with RE from 0.1°-8.3°. For IMC, AE for goniometry was 5.3° to 12.5°, with RE ranging from 0.1° to 11.1°. Principal Conclusions: Neither goniometry nor IMC appeared superior to the other in JPS assessment. Caution should be made when considering the reliability for goniometry and IMC before clinical assessment is made

    Electron Electric Dipole Moment from Lepton Flavor Violation

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    The general Minimal Supersymmetric Standard Model introduces new sources for Lepton Flavor Violation (LFV) as well as CP-violation. In this paper, we show that when both sources are present, the electric dipole moment of the electron, ded_e, receives a contribution from the phase of the trilinear AA-term of staus, ϕAτ\phi_{A_\tau}. For ϕAτ=π/2\phi_{A_\tau}=\pi/2, the value of ded_e, depending on the ratios of the LFV mass elements, can range between zero and three orders of magnitude above the present bound. We show that the present bound on ded_e rules out a large portion of the CP-violating and the LFV parameter space which is consistent with the bounds on the LFV rare decays. We show that studying the correlation between ded_e and the P-odd asymmetry in τeγ\tau \to e\gamma helps us to derive a more conclusive bound on ϕAτ\phi_{A_\tau} We also discuss the possibility of cancelation among the contributions of different CP-violating phases to ded_e.Comment: 35 pages, 9 figure
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