8,652 research outputs found

    Theoretical Summary of the HADRON99 conference

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    The Constituent Quark Model has provided a remarkable description of the experimentally observed hadron spectrum but still has no firm theoretical basis. Attempts to provide a QCD justification discussed at Hadron99 include QCD Sum Rules, instantons, relativistic potential models and the lattice. Phenomenological analyses to clarify outstanding problems like the nature of the scalar and pseudoscalar mesons and the low branching ratio for ψρπ\psi' \to \rho-\pi were presented. New experimental puzzles include the observation of pˉpϕπ\bar p p \to \phi \pi.Comment: 10 pages, espcrc1.st

    Puzzles in Hyperon, Charm and Beauty Physics

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    Puzzles awaiting better experiments and better theory include: (1) the contradiction between good and bad SU(3) baryon wave functions in fitting Cabibbo theory for hyperon decays, strangeness suppression in the sea and the violation of the Gottfried Sum rule - no model fits all; (2) Anomalously enhanced Cabibbo-suppressed D+K+(sdˉ)D^+ \to K^{*+}(s\bar d) decays; (3) anomalously enhanced and suppressed BηXB \to \eta' X decays; (4) the OZI rule in weak decays; (5) Vector dominance (Wπ,ρ,a1,Ds,DsW \to \pi, \rho, a_1, D_s, D^*_s ) in weak decays (6) Puzzles in doubly-cabibbo-suppressed charm decays.(7) Problems in obtaining Λ\Lambda spin structure from polarization measurements of produced Λ\Lambda's.Comment: 5 page

    How to Use Weak Decays in Analyses of Data on Nucleon Spin Structure Functions

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    The use of weak decays to determine proton spin structure is examined in view of possible violations of the Bjorken and Gottfried Sum rules, flavor symmetry breaking and flavor asymmetry in the sea. The use of the neutron decay is found to be unaffected by all these. A method for including these effects in analyses of hyperon decays shows that a flavor-asymmetric sea produced by SU(3) symmetry breaking has only a small effect on results for the total spin carried by quarks. However the strange quark contribution cannot be reliably obtained from charged lepton scattering and weak decay data alone, and requires additional model-dependent input relating nucleon and hyperon wave functions.Comment: 10 pages, Weizmann Report WIS-94/24/May-PH, Tel Aviv Report TAUP 2165-9

    Application of M\"ossbauer-Type Sum Rules for BB Meson Decays

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    Sum rules originally derived for the M\"ossbauer Effect are applied to weak semileptonic B decays. The sum rules follow from assuming that the decay by electroweak boson emission of an unstable nucleus or heavy quark in a bound system is described by a pointlike coupling to a current which acts only on the decaying object, that the Hamiltonian of the bound state depends on the momentum of the decaying object only in the kinetic energy and that the boson has no final state interactions. The decay rate and the first and second moments of the boson energy spectrum for fixed momentum transfer are shown to be the same as for a noninteracting gas of such unstable objects with a momentum distribution the same as that of the bound state. B meson semileptonic decays are shown to be dominated by the lowest-lying states in the charmed meson spectrum.Comment: 9 page

    FSI Rescattering in B±B^\pm Decays via States with η,η,ω\eta, \eta', \omega and ϕ\phi

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    New results going beyond those obtained from isospin and flavor symmetry and subject to clear experimental tests are obtained for effects of FSI in B±B^\pm decays to charmless strange final states containing neutral flavor-mixed mesons like ω\omega, ϕ\phi, η\eta and η\eta'. The most general strong-interaction diagrams containing arbitrary numbers of quarks and gluons are included with the assumptions that any qqˉq \bar q pair created by gluons must be a flavor singlet, and that there are no hairpin diagrams in which a final meson contains a qqˉq \bar q pair from the same gluon vertex. The smallness of KηK^- \eta suggests that it might have a large CP violation. A sum rule is derived to test whether the large KηK^- \eta' requires the addition of an additional glueball or charm admixture. Further analysis from DsD_s decay systematics supports this picture of FSI and raises questions about charm admixture in the η\eta'

    Theories of Non-Experiments in Coherent Decays of Neutral Mesons

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    Many theoretical calculations of subtle coherent effects in quantum mechanics do not carefully consider the interface between their calculations and experiment. Calculations for gedanken experiments using initial states not satisfied in realistic experiments give results requiring interpretation. Confusion and ambiguities frequently arise. Calculations for time-dependent mixing oscillations describe non-experiments. Physical experiments describe oscillations in space in the laboratory system resulting from interference between waves having the same energy and time dependence; notnot different momenta and space dependence. Time-dependent oscillations are not observed.Comment: 8 page

    Sieving Through the Data to Find the Person: HR’s Imperative for Balancing Big Data with People Centricity

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    [Excerpt] With “big data” and “analytics” atop human resources (HR) professionals’ dictionaries, it is no wonder that some are calling it time to think of employees as data points and to scientifically make people decisions. These beget horrific images of what many employees already believe HR promotes: incessant change and downsizing solely for profit maximization. Yet, for HR to genuinely transition into the world of data-driven people solutions, it must leverage its roots in employee advocacy, understanding, and development. To best do this, HR must undertake three actions. First, HR can ease into people analytics, using the necessary time and effort to gain employee buy-in. Second, HR should stress the objectivity of data-driven decision making. Third, HR practitioners must exhibit empathy for those affected by such decisions

    Systematics of Large Axial Vector Meson Production in Heavy Flavor Weak Decays

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    Branching ratios observed for DD and B decays to final states a1(1260)±Xa_1(1260)^{\pm} X are comparable to those for corresponding decays to π±X\pi^{\pm} X and ρ±X\rho^{\pm} X and much larger than those for all other decays. Implications are discussed of a "vector-dominance model" in which a WW is produced and immediately turns into an axial vector, vector or pseudoscalar meson. Data for decays to all such final states are shown to have large branching ratios and satisfy universality relations. Upper limits on small strong phase differences between amplitudes relevant to CP violation models are obtained from analysis of the predicted and observed suppression of BoB^o decays into neutral final states πoXo\pi^o X^o, ρoXo\rho^oX^o and a1oXoa_1^o X^o. . Branching ratios of 1\approx 1% are predicted for the as yet unobserved presence of the Ds1(2536)D_{s1}(2536) charmed-strange axial vector in B decays.Comment: 14 page

    A Musician\u27s Prayer

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