699 research outputs found

    Remarks on Semileptonic B and D Decays into Orbitally Excited Mesons

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    We have obtained the differential decay rate and calculated the branching ratios of the exclusive semileptonic decays B(D)XlνB(D) \to Xl\nu, where XX is a p-wave meson, using the nonrelativistic ISGW quark model. Our results are compared with the predictions of the ISGW2 model. We have computed some branching ratios that were not reported or were reported with 0.00 in this model. For example, we find that Br(BcBs20ˉlνˉ)=4.03×105Br(B_c^- \to \bar{B_{s2}^{*0}}l^-\bar{\nu}) = 4.03 \times 10^{-5}, Br(BcB20ˉlνˉ)=3.65×106Br(B_c^- \to \bar{B_2^{*0}}l^- \bar{\nu}) =3.65 \times 10^{-6} and Br(Ds+f2l+ν)=2.7×105Br(D_s^+ \to f_2l^+\nu) = 2.7 \times 10^{-5}, which seems to be at the reach of forthcoming experiments. Furthermore, we have classified the Bu,d,sTlνB_{u,d,s} \to Tl\nu decays in two groups and compared the semileptonic and nonleptonic decays including a tensor meson in the final state.Comment: 11 pages, LaTe

    Non-Hermitian SUSY Hydrogen-like Hamiltonians with real spectra

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    It is shown that the radial part of the Hydrogen Hamiltonian factorizes as the product of two not mutually adjoint first order differential operators plus a complex constant epsilon. The 1-susy approach is used to construct non-hermitian Hamiltonians with hydrogen spectra. Other non-hermitian Hamiltonians are shown to admit an extra `complex energy' at epsilon. New self-adjoint hydrogen-like Hamiltonians are also derived by using a 2-susy transformation with complex conjugate pairs epsilon, (c.c) epsilon.Comment: LaTeX2e file, 13 pages, 6 EPS figures. New references added. The present is a reorganized and simplified versio

    Young Women With Type 1 Diabetes Have Lower Bone Mineral Density That Persists Over Time

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    OBJECTIVE—Individuals with type 1 diabetes have decreased bone mineral density (BMD), yet the natural history and pathogenesis of osteopenia are unclear. We have previously shown that women with type 1 diabetes (aged 13–35 years) have lower BMD than community age-matched nondiabetic control subjects. We here report 2-year follow-up BMD data in this cohort to determine the natural history of BMD in young women with and without diabetes

    3D magnetic configuration of ferrimagnetic multilayers with competing interactions visualized by soft X ray vector tomography

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    Full control of magnetic properties in exchange coupled systems requires a good understanding of 3D magnetic configuration with lateral and in depth resolution. Here we show results from a soft X ray tomographic reconstruction which allow determining, solely from the experimental data, a detailed description of the vector magnetic configuration of a ferrimagnetic Gd12Co88 Nd17Co83 Gd24Co76 trilayer with engineered competing anisotropy, exchange and magneto static interactions at different depths. The trilayer displays chevron patterns with a distorted closure structure. Near the top Gd24Co76 layer, local exchange springs with out of plane magnetization reversal, quasi domains with ripple like patterns and magnetic vortices and antivortices across the thickness are observed. The detailed analysis of the magnetic tomogram shows that the effective strength of the exchange spring at the NdCo GdCo interface can be finely tuned by GdxCo1 x composition and anisotropy determined by sample fabrication and in plane stripe orientation adjustable , demonstrating the suitability of 3D magnetic visualization techniques in magnetic engineering researc

    Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η\eta|<0.8) and transverse momentum range 0.2< pTp_{\rm T}< 5.0 GeV/cc. The elliptic flow signal v2_2, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ±\pm 0.002 (stat) ±\pm 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v2(pT)_2(p_{\rm T}) reaches a maximum of 0.2 near pTp_{\rm T} = 3 GeV/cc. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389
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