6,653 research outputs found

    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

    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

    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

    New Quark Relations for Hadron Masses and Magnetic Moments - A Challenge for Explanation from QCD

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    Prompted by the recent surprising results in QCD spectroscopy, we extend the treatment of the constituent quark model showing that mass differences and ratios have the same values when obtained from mesons and baryons. We obtain several new successful relations involving hadrons containing two and three strange quarks and hadrons containing heavy quarks and give a new prediction regarding spin splitting between doubly charmed baryons. We provide numerical evidence for an effective supersymmetry between mesons and baryons related by replacing a light antiquark by a light diquark. We also obtain new relations between quark magnetic moments and hadron masses. Limits of validity of this approach and disagreements with experiment in properties of the Sigma and Xi baryons are discussed as possible clues to a derivation from QCD.Comment: Presentation improved, references added, typos correcte

    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

    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

    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 η\eta' are discussed.Comment: special macro - phyzz

    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'

    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
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