5,674 research outputs found

    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 B→ηâ€ČXB \to \eta' X decays; (4) the OZI rule in weak decays; (5) Vector dominance (W→π,ρ,a1,Ds,Ds∗W \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

    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 ψâ€Č→ρ−π\psi' \to \rho-\pi were presented. New experimental puzzles include the observation of pˉp→ϕπ\bar p p \to \phi \pi.Comment: 10 pages, espcrc1.st

    What is coherent in neutrino oscillations

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    Simple rigorous quantum mechanics with no hand waving nor loopholes clarifies the confusion between three contradictory descriptions of neutrino oscillations: (1)The time oscillations shown in standard textbooks produced by neutrino eigenstates with different masses and different energies. (2) That time oscillations and interference between states having different energies cannot be observed in realistic experiments. (3) That interference between different neutrino mass eigenstates is not observable in "missing mass" experiments where information determining the neutrino mass is available from other particles measured in production or detection vertices. Quantum-mechanical ignorance of the neutrino momentum is rigorously shown to be imposed by all realistic detectors and to produce coherence between amplitudes from neutrino states with the same energy and different masses. Conditions are precisely formulated for the loss of coherence when mass eigenstate wave packets moving with different velocities separate. The example of Bragg scattering shows how quantum-mechanically imposed ignorance produces coherence.Comment: 13 pages, Abstract and text of original contribution completely revise

    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

    Penguins, Trees and Final State Interactions in B Decays in Broken SU3

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    The availability of data on BsB_s decays to strange quasi-two-body final states, either with or without charmonium opens new possibilities for understanding different contributions of weak diagrams and in particular the relative contributions of tree and penguin diagrams. Corresponding BdB_d and BsB_s decays to charge conjugate final states are equal in the SU(3) symmetry limit and the dominant SU(3) breaking mechanism is given by ratios of CKM matrix elements. Final State Interactions effects should be small, because strong interactions conserve CC and should tend to cancel in ratios between charge conjugate states. Particularly interesting implications of decays into final states containing η\eta and ηâ€Č\eta' are discussed.Comment: special macro - phyzz

    FSI Rescattering in B±B^\pm Decays via States with η,ηâ€Č,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 ηâ€Č\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 K−ηK^- \eta suggests that it might have a large CP violation. A sum rule is derived to test whether the large K−ηâ€ČK^- \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 ηâ€Č\eta'

    Puzzles in Cabibbo-Suppressed Charm Decays

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    We identify two Cabibbo suppressed D+D^+ decay modes with anomalously high branching ratios which are not simply explained by any model. All standard model diagrams that can contribute to these decays are related by symmetries to diagrams for other decays that do not show any such enhancement. If these high branching ratios are confirmed by more precise experiments, they may require new physics to explain them. Anomalies in DsD_s decays and tests for possible violation of G-parity are discussed.Comment: 12 pages, additional clarification at eq. (13), correction of error in eq. (18) and subsequent discussio

    A Musician\u27s Prayer

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    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
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