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[en] The title of this lecture series raises two questions: (1) what is the OZI rule? (2) what is a nucleon. In the lectures both questions were addressed in parallel and the material moved back and forth between them. In a written version it seems more appropriate to treat the two question separately, begining with trying to understand the structure of the nucleon. Experimental evidence for the symmetry and quark structure of hadrons is reviewed with a historical introduction and updated by presenting constituent quark model relation for hadron masses and magnetic moments.Three definitions of the OZI rule are presented, all which forbid decay like φ->ρπ but making different selection rules for more complicate reactions. All suffer from the higer order paradox that a forbidden process can take place via two-step transition in which each step is allowed; e.g. φ-> KK-bar -> ρπ. No prescription is given for estimating the strength of forbidden processes. The role of cancellations between different higer order diagrams is discussed. (author)

[en] A brief review is given of the various contribution to the eleventh Rencontre de Moriond on ''New fields in hadronic physics''. It is especially noted that almost all the talks used the language and the physical picture of hadrons as being composed of simple entities: quarks

[en] Heavy-quark effective theory (HQET) is applied to lattice QCD with Wilson fermions at fixed lattice spacing a. This description is possible because heavy-quark symmetries are respected. It is desirable because the ultraviolet cutoff 1/a in current numerical work and the heavy-quark mass m_Q are comparable. Effects of both short distances a and 1/m_Q are captured fully into coefficient functions, which multiply the operators of the usual HQET. Standard tools of HQET are used to develop heavy-quark expansions of lattice observables and, thus, to propagate heavy-quark discretization errors. Three explicit examples are given: namely, the mass, decay constant, and semileptonic form factors of heavy-light mesons. (c) 2000 The American Physical Society

[en] The quark, mathematically introduced as a state of the SU(3) triplet, allows the charge of every known boson to be simply described. Theoretical studies have shown the quark model to be also usable as a hadron theory in a phenomenological way. The introduction of quarks among real particles entails the definition of some new quantum numbers (color, charm) together with the principle of quark confinement, and the gluon and bag models

[en] Some simple aspects of spectroscopic consequences and expected exchange mechanisms in the colour isomer multiquark model are showed

[en] The paradoxical combination in the new PSI particles of heaviness (3.1, 3.7 and 4.2GeV) and narrowness has led to the introduction of a new quantum number, charm, in a four-quark model including charmed particles: mesons and baryons

[en] The quark exchange formalism is formulated to calculate the quark momentum distribution in the iso-scalar lithium nucleus. Then by boosting the nucleus to an infinite momentum frame, the lithium structure function is evaluated at different nucleon “sizes”, i.e., b = 0.7, 0.8, 0.9 and 1 fm and the Bjorken scale (x) values. It is shown that the lithium structure function becomes narrower, and it is pushed to the smaller x values, as the nucleon size is increased. Similar to our previous works for three nucleon systems, the lithium nucleus European muon collaboration (EMC) ratio decreases, as we increase the x and b values and it shows larger effect, with respect to the free nucleon and three nucleons iso-scalar nucleus. On the other hand, present calculation of the EMC ratio for lithium nucleus shows a good agreement with the corresponding NMC data, which is available for 1.4 × 10"-"4 ≤ x ≤ 0.65. Since the atomic number is still small (A = 6), in this work as usual, we ignore the possibility of simultaneous exchange of quarks between more than two nucleons, which can be important as one moves to the heavy nuclei. Although, according to Hen et al., in the neutron rich nuclei the protons have a greater probability than neutrons to have momentum greater than the Fermi momentum, the three-body contribution may be suppressed. (author)

[en] In the last few years many new unexpected new particles have been discovered in the analysis of B-factories data. In the charm sector, the newly discovered D_s mesons are difficult to explain within potential models. In the charmonium sector, the large variety of new states are difficult to accommodate in the quark model and some of them are candidates for being hybrids or 4-quark states. Results will be presented on charm and charmonium spectroscopy from BaBar experiment using inclusive e⁺e^- interactions, B decays and exclusive ISR reactions.

[en] On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation function. We then propose a confining Nambu-Jona-Lasinio-type model. The confinement is implemented in analogy to Anderson localization in condensed matter systems. We study the model's phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density