1,663 research outputs found

    The Spin Structure of the Constituent Quarks and of the Nucleon

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    We define a constituent quark within QCD. It is shown that the spin of such a quark and hence also the spin of the nucleon reduced due to qˉq\bar{q}q-pairs, in agreement with experiment. A solution to the spin problem is given.Comment: 7 page

    Quark Mass Hierarchies, Flavor Mixing and Maximal CP-Violation

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    Flavor mixing and the quark mass spectrum are intimately related. In view of the observed strong hierarchy of the quark and lepton masses and of the flavor mixing angles it is argued that the description of flavor mixing must take this into account. One particular interesting way to describe the flavor mixing emerges, which is particularly suited for models of quark mass matrices based on flavor symmetries. We conclude that the unitarity triangle important for BB physics should be close to or identical to a rectangular triangle. CPCP violation is maximal in this sense.Comment: 21 latex page

    The Physics of Flavor is the Flavor of Physics

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    Summary Talk: International Conference of Flavor Physics (ICFP 2001). Zhang-Jia-Jie. Hunan, China (May / June 2001)Comment: 10 page

    The Breaking of Isospin and the rho-omega-System

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    Simple quark models for the low lying vector mesons suggest a mixing between the u- and d-flavors and a violation of the isospin symmetry for the rho-omega system much stronger than observed. It is shown that the chiral dynamics, especially the QCD anomaly, is responsible for a restoration of the isospin symmetry in the rho-omega system.Comment: 6 pages, style file appolb.cls include

    The breaking of the flavour permutational symmetry: Mass textures and the CKM matrix

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    Different ansaetze for the breaking of the flavour permutational symmetry according to S(3)L X S(3)R in S(2)L X S(2) give different Hermitian mass matrices of the same modified Fritzsch type, which differ in the symmetry breaking pattern. In this work we obtain a clear and precise indication on the preferred symmetry breaking scheme from a fit of the predicted theoretical Vckm to the experimentally determined absolute values of the elements of the CKM matrix. The preferred scheme leads to simple mass textures and allows us to compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner angles of the unitarity triangle in terms of four quark mass ratios and only one free parameter: the CP violating phase Phi. Excellent agreement with the experimentally determined absolute values of the entries in the CKM matrix is obtained for Phi = 90 deg. The corresponding computed values of the Jarlskog invariant and the inner angles are J = 3.00 X 10^-5, alpha= 84 deg, beta= 24 deg and gamma =72 deg in very good agreement with current data on CP violation in the neutral kaon-antikaon system and oscillations in the B-Bbar system.Comment: 21 pages, 1 fig. Content enlarged, references added and typos corrected. To be published in Phys Rev

    The Origin of Mass

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    The quark-lepton mass problem and the ideas of mass protection are reviewed. The hierarchy problem and suggestions for its resolution, including Little Higgs models, are discussed. The Multiple Point Principle is introduced and used within the Standard Model to predict the top quark and Higgs particle masses. Mass matrix ans\"{a}tze are considered; in particular we discuss the lightest family mass generation model, in which all the quark mixing angles are successfully expressed in terms of simple expressions involving quark mass ratios. It is argued that an underlying chiral flavour symmetry is responsible for the hierarchical texture of the fermion mass matrices. The phenomenology of neutrino mass matrices is briefly discussed.Comment: 33 pages, 7 figures, to be published in the Proceedings of the XXXI ITEP Winter School, Moscow, Russia, 18 - 26 February 200

    Maximal Neutrino Mixing and Maximal CP Violation

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    We propose a phenomenological model of lepton mixing and CP violation based on the flavor democracy of charge leptons and the mass degeneracy of neutrinos. A nearly bi-maximal flavor mixing pattern, which is favored by current data on atmospheric and solar neutrino oscillations, emerges naturally from this model after explicit symmetry breaking. The rephasing-invariant strength of CP or T violation can be as large as one percent, leading to significant probability asymmetries between \nu_\mu \to \nu_e and \bar{\nu}_\mu \to \bar{\nu}_e (or \nu_e \to \nu_\mu) transitions in the long-baseline neutrino experiments.Comment: LaTex 12 pages (2 figures included
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