1,663 research outputs found

### The Spin Structure of the Constituent Quarks and of the Nucleon

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 $\bar{q}q$-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

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 $B$
physics should be close to or identical to a rectangular triangle. $CP$
violation is maximal in this sense.Comment: 21 latex page

### The Physics of Flavor is the Flavor of Physics

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

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

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

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

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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