904 research outputs found

    An Analysis of B_s Decays in the Left-Right-Symmetric Model with Spontaneous CP Violation

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    Non-leptonic B_s decays into CP eigenstates that are caused by \bar b -> \bar cc\bar s quark-level transitions, such as B_s -> D_s^+D^-_s, J/psi eta^(') or J/psi phi, provide a powerful tool to search for ``new physics'', as the CP-violating effects in these modes are tiny in the Standard Model. We explore these effects for a particular scenario of new physics, the left-right-symmetric model with spontaneous CP violation. In our analysis, we take into account all presently available experimental constraints on the parameters of this model, i.e. those implied by K- and B-decay observables; we find that CP asymmetries as large as O(40%) may arise in the B_s channels, whereas the left-right-symmetric model favours a small CP asymmetry in the ``gold-plated'' mode B_d -> J/psi K_S. Such a pattern would be in favour of B-physics experiments at hadron machines, where the B_s modes are very accessible.Comment: 12 pages, 5 figure

    Solar astronomy

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    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research

    Temperature and Emission-Measure Profiles Along Long-Lived Solar Coronal Loops Observed with TRACE

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    We report an initial study of temperature and emission measure distributions along four steady loops observed with the Transition Region and Coronal Explorer (TRACE) at the limb of the Sun. The temperature diagnostic is the filter ratio of the extreme-ultraviolet 171-angstrom and 195-angstrom passbands. The emission measure diagnostic is the count rate in the 171-angstrom passband. We find essentially no temperature variation along the loops. We compare the observed loop structure with theoretical isothermal and nonisothermal static loop structure.Comment: 10 pages, 3 postscript figures (LaTeX, uses aaspp4.sty). Accepted by ApJ Letter

    and

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    We study experimentally the flow of a liquid metal confined between differentially rotating cylinders, in the presence of externally imposed axial and azimuthal magnetic fields. For increasingly large azimuthal fields a wavelike disturbance arises, traveling along the axis of the cylinders. The wavelengths and speeds of these structures, as well as the field strengths and rotation rates at which they arise, are broadly consistent with theoretical predictions of such a traveling-wave magnetorotational instability. Subject headings: instabilities — MHD — waves 1

    Spin-Orbit and Tensor Forces in Heavy-quark Light-quark Mesons: Implications of the New Ds state at 2.32 GeV

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    We consider the spectroscopy of heavy-quark light-quark mesons with a simple model based on the non-relativistic reduction of vector and scalar exchange between fermions. Four forces are induced: the spin-orbit forces on the light and heavy quark spins, the tensor force, and a spin-spin force. If the vector force is Coulombic, the spin-spin force is a contact interaction, and the tensor force and spin-orbit force on the heavy quark to order 1/m1m21/m_1m_2 are directly proportional. As a result, just two independent parameters characterize these perturbations. The measurement of the masses of three p-wave states suffices to predict the mass of the fourth. This technique is applied to the DsD_s system, where the newly discovered state at 2.32 GeV provides the third measured level, and to the DD system. The mixing of the two JP=1+J^P=1^+ p-wave states is reflected in their widths and provides additional constraints. The resulting picture is at odds with previous expectations and raises new puzzles.Comment: 6 pages, 1 figur

    Perioperative donor bone marrow infusion augments chimerism in heart and lung transplant recipients

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    Background.: We and others have demonstrated that a low level of donor cell chimerism was present for years after transplantation in tissues and peripheral blood of heart and lung recipients; it was associated, in the latter, with a lower incidence of chronic rejection. To augment this phenomenon, we initiated a trial combining simultaneous infusion of donor bone marrow with heart or lung allotransplantation. Methods.: Between September 1993 and January 1995, 15 nonconditioned patients received either heart (n = 10) or lung (n = 5) allografts concurrently with an infusion of unmodified donor bone marrow (3.0 × 108 cells/kg), and were maintained on an immunosuppressive regimen consisting of tacrolimus and steroids. Results.: There was no complication associated with the infusion of donor bone marrow. Chimerism was detectable in 73% of bone marrow-augmented patients up to the last sample tested. Of the 5 control recipients who did not receive bone marrow infusion, only 1 had detectable chimerism by flow on postoperative day 15, which dwindled to an undetectable level by postoperative day 36. None of the patients had evidence of donor-specific immune modulation by mixed lymphocyte reaction. Conclusions.: The combined infusion of donor bone marrow and heart or lung transplantation, without preconditioning of the recipient, is safe and is associated with an augmentation of donor cell chimerism. © 1995 The Society of Thoracic Surgeons

    CP violation and the CKM angle γ\gamma from angular distributions of untagged BsB_s decays governed by bˉcˉusˉ\bar b\to\bar c u\bar s

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    We demonstrate that time-dependent studies of angular distributions for BsB_s decays caused by bˉcˉusˉ\bar b\to\bar cu\bar s quark-level transitions extract cleanly and model-independently the CKM angle γ\gamma. This CKM angle could be cleanly determined from untagged BsB_s decays alone, if the lifetime difference between the BsB_s mass eigenstates BsLB_s^L and BsHB_s^H is sizable. The time-dependences for the relevant tagged and untagged observables are given both in a general notation and in terms of linear polarization states and should exhibit large CP-violating effects. These observables may furthermore provide insights into the hadronization dynamics of the corresponding exclusive BsB_s decays thereby allowing tests of the factorization hypothesis.Comment: 14 pages, LaTeX, no figure

    Studying New Physics Amplitudes in Charmless B_s Decays

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    A method based on flavour SU(3) is proposed for identifying and extracting New Physics (NP) amplitudes in charmless ΔS=1\Delta S=1 BsB_s decays using time-dependent CP asymmetries in these decays and in flavour SU(3) related ΔS=0\Delta S=0 decays. For illustration, we assume a hierarchy, 1:λ:λ2\sim 1: \lambda : \lambda^2 (λ=0.2\lambda=0.2), between a dominant ΔS=1\Delta S=1 penguin amplitude, a NP amplitude and a Standard Model amplitude with weak phase γ\gamma. An uncertainty from SU(3) breaking corrections, reduced by using ratios of hadronic amplitudes, is further suppressed by a factor λ\lambda. We discuss examples for pairs of decays into two neutral vector mesons, Bsϕϕ,BsϕKˉ0B_s\to\phi\phi, B_s\to\phi \bar K^{*0} and BsK0Kˉ0,B0K0Kˉ0B_s\to K^{*0}\bar K^{*0}, B^0\to K^{*0}\bar K^{*0}, where the magnitude of the NP amplitude, its weak and strong phases can be determined.Comment: typo corrected, reference added, submitted to Physics Letters
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