42 research outputs found

    The missing sinks: slip localization in faults, damage zones, and the seismic energy budget

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    Semileptonic and nonleptonic B decays to three charm quarks: B->J/psi (eta_c) D l nu and J/psi (eta_c) D pi

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    We evaluate the form factors describing the semileptonic decays B0ˉ→J/ψ(ηc)D+ℓ−Μˉℓ\bar{B^0}\to J/\psi (\eta_c) D^+ \ell^- \bar \nu_\ell, within the framework of a QCD relativistic potential model. This decay is complementary to B0ˉ→J/ψ(ηc)D+π−\bar{B^0}\to J/\psi (\eta_c) D^+ \pi^- in a phase space region where a pion factors out.We estimate the branching ratio for these semileptonic and nonleptonic channels, finding BR(B0ˉ→J/ψ(ηc)D+ℓΜℓ)≃10−13\mathcal{BR}(\bar{B^0} \to J/\psi (\eta_c) D^+ \ell \nu_\ell) \simeq 10^{-13}, BR(B0ˉ→J/ψD+π−)=3.1×10−8\mathcal{BR}(\bar{B^0} \to J/\psi D^+ \pi^-) = 3.1 \times 10^{-8} and BR(B0ˉ→ηcD+π−)=3.5×10−8\mathcal{BR}(\bar{B^0} \to \eta_c D^+ \pi^-) = 3.5 \times 10^{-8}.Comment: 14 pages, 4 figure

    Exploring skewed parton distributions with two body models on the light front II: covariant Bethe-Salpeter approach

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    We explore skewed parton distributions for two-body, light-front wave functions. In order to access all kinematical regimes, we adopt a covariant Bethe-Salpeter approach, which makes use of the underlying equation of motion (here the Weinberg equation) and its Green's function. Such an approach allows for the consistent treatment of the non-wave function vertex (but rules out the case of phenomenological wave functions derived from ad hoc potentials). Our investigation centers around checking internal consistency by demonstrating time-reversal invariance and continuity between valence and non-valence regimes. We derive our expressions by assuming the effective qq potential is independent of the mass squared, and verify the sum rule in a non-relativistic approximation in which the potential is energy independent. We consider bare-coupling as well as interacting skewed parton distributions and develop approximations for the Green's function which preserve the general properties of these distributions. Lastly we apply our approach to time-like form factors and find similar expressions for the related generalized distribution amplitudes.Comment: 25 pages, 12 figures, revised (minor changes but essential to consistency

    Semi-Analytic Approach to Higher-Order Corrections in Simple Muonic Bound Systems: Vacuum Polarization, Self-Energy and Radiative-Recoil

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    The current discrepancy of theory and experiment observed recently in muonic hydrogen necessitates a reinvestigation of all corrections to contribute to the Lamb shift in muonic hydrogen muH, muonic deuterium muD, the muonic 3He ion, as well as in the muonic 4He ion. Here, we choose a semi-analytic approach and evaluate a number of higher-order corrections to vacuum polarization (VP) semi-analytically, while remaining integrals over the spectral density of VP are performed numerically. We obtain semi-analytic results for the second-order correction, and for the relativistic correction to VP. The self-energy correction to VP is calculated, including the perturbations of the Bethe logarithms by vacuum polarization. Subleading logarithmic terms in the radiative-recoil correction to the 2S-2P Lamb shift of order alpha (Zalpha)^5 mu^3 ln(Zalpha)/(m_mu m_N) are also obtained. All calculations are nonperturbative in the mass ratio of orbiting particle and nucleus.Comment: 10 pages; svjour style; to appear in the European Physical Journal

    Baryon Tri-local Interpolating Fields

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    We systematically investigate tri-local (non-local) three-quark baryon fields with U_L(2)*U_R(2) chiral symmetry, according to their Lorentz and isospin (flavor) group representations. We note that they can also be called as "nucleon wave functions" due to this full non-locality. We study their chiral transformation properties and find all the possible chiral multiplets consisting J=1/2 and J=3/2 baryon fields. We find that the axial coupling constant |g_A| = 5/3 is only for nucleon fields belonging to the chiral representation (1/2,1)+(1,1/2) which contains both nucleon fields and Delta fields. Moreover, all the nucleon fields belonging to this representation have |g_A| = 5/3.Comment: 8 pages, 3 tables, accepted by EPJ

    B→KB\to K Transition Form Factor up to O(1/mb2){\cal O}(1/m^2_b) within the kTk_T Factorization Approach

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    In the paper, we apply the kTk_T factorization approach to deal with the B→KB\to K transition form factor F+,0B→K(q2)F^{B\to K}_{+,0}(q^2) in the large recoil regions. The B-meson wave functions ΚB\Psi_B and ιˉB\bar\Psi_B that include the three-particle Fock states' contributions are adopted to give a consistent PQCD analysis of the form factor up to O(1/mb2){\cal O} (1/m^2_b). It has been found that both the wave functions ΚB\Psi_B and ιˉB\bar\Psi_B can give sizable contributions to the form factor and should be kept for a better understanding of the BB meson decays. Then the contributions from different twist structures of the kaon wavefunction are discussed, including the SUf(3)SU_f(3)-breaking effects. A sizable contribution from the twist-3 wave function Κp\Psi_p is found, whose model dependence is discussed by taking two group of parameters that are determined by different distribution amplitude moments obtained in the literature. It is also shown that F+,0B→K(0)=0.30±0.04F^{B\to K}_{+,0}(0)=0.30\pm0.04 and [F+,0B→K(0)/F+,0B→π(0)]=1.13±0.02[F^{B\to K}_{+,0}(0)/F^{B\to \pi}_{+,0}(0)]=1.13\pm0.02, which are more reasonable and consistent with the light-cone sum rule results in the large recoil regions.Comment: 22 pages and 6 figure

    Isgur-Wise Function for Λb→Λc\Lambda_b \to \Lambda_c in B-S Approach

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    In the heavy quark limit, the heavy baryon ΛQ\Lambda_Q (Q=b or c) can be regarded as composed of a heavy quark and a scalar light diquark which has good spin and flavor quantum numbers. Based on this picture we establish the Bethe-Salpeter (B-S) equation for ΛQ\Lambda_Q in the leading order of 1/mQ1/m_Q expansion. With the kernel containing both the scalar confinement and one-gluon-exchange terms we solve the B-S equation numerically. The Isgur-Wise function for Λb→Λc\Lambda_b \to \Lambda_c is obtained numerically from our model. Comparison with other model calculations are also presented. It seems that the Isgur-Wise function for Λb→Λc\Lambda_b \to \Lambda_c drops faster than that for B→DB \to D. The differential and total decay widths for Λb→ΛclΜˉ\Lambda_b \to \Lambda_c l \bar{\nu} are given in the limit mb,c→∞m_{b,c}\to \infty.Comment: 14 pages, 4 Postscript figure

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair
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