7,793 research outputs found

    Fast CP Violation

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    BB flavor tagging will be extensively studied at the asymmetric BB factories due to its importance in CP asymmetry measurements. The primary tagging modes are the semileptonic decays of the bb (lepton tag), or the hadronic bc(s)b \to c (\to s) decays (kaon tag). We suggest that looking for time dependent CP asymmetries in events where one BB is tagged leptonically and the other one is tagged with a kaon could result in an early detection of CP violation. Although in the Standard Model these asymmetries are expected to be small, 1\sim 1%, they could be measured with about the same amount of data as in the ``gold-plated'' decay BdψKSB_d \to \psi K_S. In the presence of physics beyond the Standard Model, these asymmetries could be as large as 5\sim 5%, and the first CP violation signal in the BB system may show up in these events. We give explicit examples of new physics scenarios where this occurs.Comment: 9 pages, revtex, no figures. Discussion of new physics effects on CP violation with two lepton tags expanded. Factors of 2 correcte

    A non-associative quantum mechanics

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    A non-associative quantum mechanics is proposed in which the product of three and more operators can be non-associative one. The multiplication rules of the octonions define the multiplication rules of the corresponding operators with quantum corrections. The self-consistency of the operator algebra is proved for the product of three operators. Some properties of the non-associative quantum mechanics are considered. It is proposed that some generalization of the non-associative algebra of quantum operators can be helpful for understanding of the algebra of field operators with a strong interaction.Comment: one typo in Eq. (23) is correcte

    B-Decay CP Asymmetries, Discrete Ambiguities and New Physics

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    The first measurements of CP violation in the BB system will likely probe sin2α\sin 2\alpha, sin2β\sin 2\beta and cos2γ\cos 2\gamma. Assuming that the CP angles α\alpha, β\beta and γ\gamma are the interior angles of the unitarity triangle, these measurements determine the angle set (α,β,γ)(\alpha,\beta,\gamma) except for a twofold discrete ambiguity. If one allows for the possibility of new physics, the presence of this discrete ambiguity can make its discovery difficult: if only one of the two candidate solutions is consistent with constraints from other measurements in the BB and KK systems, one is not sure whether new physics is present or not. We review the methods used to resolve the discrete ambiguity and show that, even in the presence of new physics, they can usually be used to uncover this new physics. There are some exceptions, which we describe in detail. We systematically scan the parameter space and present examples of values of (α,β,γ)(\alpha,\beta,\gamma) and the new-physics parameters which correspond to all possibilities. Finally, we show that if one relaxes the assumption that the bag parameters \BBd and \BK are positive, one can no longer definitively establish the presence of new physics.Comment: 29 pages, LaTeX, 1 figures, presentation substantially reworked, physics conclusions unchanged. This version will be published in Phys. Rev.

    Detecting synchronization of self-sustained oscillators by external driving with varying frequency

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    We propose a method for detecting the presence of synchronization of self-sustained oscillator by external driving with linearly varying frequency. The method is based on a continuous wavelet transform of the signals of self-sustained oscillator and external force and allows one to distinguish the case of true synchronization from the case of spurious synchronization caused by linear mixing of the signals. We apply the method to driven van der Pol oscillator and to experimental data of human heart rate variability and respiration.Comment: 9 pages, 7 figure

    Detection of synchronization from univariate data using wavelet transform

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    A method is proposed for detecting from univariate data the presence of synchronization of a self-sustained oscillator by external driving with varying frequency. The method is based on the analysis of difference between the oscillator instantaneous phases calculated using continuous wavelet transform at time moments shifted by a certain constant value relative to each other. We apply our method to a driven asymmetric van der Pol oscillator, experimental data from a driven electronic oscillator with delayed feedback and human heartbeat time series. In the latest case, the analysis of the heart rate variability data reveals synchronous regimes between the respiration and slow oscillations in blood pressure.Comment: 10 pages, 9 figure

    CP Violation in \tau ->\nu\pi K_S and D->\pi K_S: The Importance of K_S-K_L Interference

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    The BB-factories have measured CP asymmetries in the τπKSν\tau\to\pi K_S\nu and DKSπD\to K_S\pi modes. The KSK_S state is identified by its decay to two pions at a time that is close to the KSK_S lifetime. Within the Standard Model and many of its extensions, the asymmetries in these modes come from CP violation in K0Kˉ0K^0-\bar{K}^0 mixing. We emphasize that the interference between the amplitudes of intermediate KSK_S and KLK_L is as important as the pure KSK_S amplitude. Consequently, the measured asymmetries depend on the times over which the relevant decay rates are integrated and on features of the experiment.Comment: 4 pages, 4 figure

    Anaerobic Methane Oxidation in a Landfill-Leachate Plume

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    The alluvial aquifer adjacent to Norman Landfill, OK, provides an excellent natural laboratory for the study of anaerobic processes impacting landfill-leachate contaminated aquifers. We collected groundwaters from a transect of seven multilevel wells ranging in depth from 1.3 to 11 m that were oriented parallel to the flow path. The center of the leachate plume was characterized by (1) high alkalinity and elevated concentrations of total dissolved organic carbon, reduced iron, and methane, and (2) negligible oxygen, nitrate, and sulfate concentrations. Methane concentrations and stable carbon isotope (δ13C) values suggest anaerobic methane oxidation was occurring within the plume and at its margins. Methane δ13C values increased from about -54‰ near the source to >-10‰ downgradient and at the plume margins. The isotopic fractionation associated with this methane oxidation was -13.6±1.0‰. Methane 13C enrichment indicated that 80-90% of the original landfill methane was oxidized over the 210-m transect. Firstorder rate constants ranged from 0.06 to 0.23 per year, and oxidation rates ranged from 18 to 230µM/y. Overall, hydrochemical data suggest that a sulfate reducermethanogen consortium may mediate this methane oxidation. These results demonstrate that natural attenuation through anaerobic methane oxidation can be an important sink for landfill methane in aquifer systems

    Tau Polarization in ΛbXcτνˉ \Lambda_b \to X_c \tau \bar{\nu} and BXcτνˉB \to X_c \tau \bar{\nu}

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    We discuss the longitudinal and transverse τ\tau-polarization in inclusive decays of hadrons containing bb-quarks. The calculation is performed by means of an OPE in HQET. Some mathematical difficulties in calculating transverse polarizations are explained. Numerical results are presented for longitudinal and for transverse polarizations, both in and perpendicular to the decay plane.Comment: LATEX, 20 pages, 5 Postscript figure

    New Physics and CP Violation in Singly Cabibbo Suppressed D Decays

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    We analyze various theoretical aspects of CP violation in singly Cabibbo suppressed (SCS) D-meson decays, such as DKK,ππD \to K K,\pi \pi. In particular, we explore the possibility that CP asymmetries will be measured close to the present level of experimental sensitivity of O(102)O(10^{-2}). Such measurements would signal new physics. We make the following points: (i) The mechanism at work in neutral D decays could be indirect or direct CP violation (or both). (ii) One can experimentally distinguish between these possibilities. (iii) If the dominant CP violation is indirect, then there are clear predictions for other modes. (iv) Tree-level direct CP violation in various known models is constrained to be much smaller than 10210^{-2}. (v) SCS decays, unlike Cabibbo favored or doubly Cabibbo suppressed decays, are sensitive to new contributions from QCD penguin operators and especially from chromomagnetic dipole operators. This point is illustrated with supersymmetric gluino-squark loops, which can yield direct CP violating effects of O(102)O(10^{-2}).Comment: 36 pages, 5 figure

    Turbulent convection: comparing the moment equations to numerical simulations

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    The non-local hydrodynamic moment equations for compressible convection are compared to numerical simulations. Convective and radiative flux typically deviate less than 20% from the 3D simulations, while mean thermodynamic quantities are accurate to at least 2% for the cases we have investigated. The moment equations are solved in minutes rather than days on standard workstations. We conclude that this convection model has the potential to considerably improve the modelling of convection zones in stellar envelopes and cores, in particular of A and F stars.Comment: 10 pages (6 pages of text including figure captions + 4 figures), Latex 2e with AAS Latex 5.0 macros, accepted for publication in ApJ
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