New results on multiplicity, identified particles and spin measurements in e+e- collisions

The analyses of recent LEP data provide us with a rich ground for pQCD and LPHD tests. A number of non-trivial effects predicted in the framework of MLLA are experimentally verified. Recent measurements also enrich our knowledge about the hadronization process.Comment: 3 pages. Presented at the International Europhysics Conference High Energy Physics 99, Tampere, Finland, July, 199

Aspects of phi-meson production in proton-proton collisions

We analyze near-threshold cross section data for the reaction pp->pp phi published by the DISTO collaboration and recent, still preliminary results presented by the ANKE Collaboration. We formulate a procedure to evaluate the OZI ratio at low energies by taking into account corrections from the kinematics and the final-state interaction. Combining the new data with the few measurements available at higher energies we give a limit for the OZI rule violation and estimate the possible contribution from a five-quark baryonic resonance coupled to the phi-p system.Comment: 6 pages, 4 figure

Evidence of N*(1535) resonance contribution in the pn->d\phi reaction

The N*(1535) resonance contributions to the pn->d\phi reaction are evaluated in an effective Lagrangian model. The \pi-, \eta-, and \rho-meson exchange are considered. It is shown that the contributions from \pi- and \rho-meson exchange are dominant, while the contribution from \eta-meson exchange is negligibly small. Our theoretical results reproduce the experimental data of both total cross section and angular distribution well. This is another evidence that the N*(1535) resonance has large s\bar{s} component leading to a large coupling to N\phi, which may be the real origin of the OZI rule violation in the \piN and pN reactions.Comment: 13 pages,4 figure

Contribution of the t-channel N∗(1535)N^*(1535) exchange for the ppˉ→ϕϕp\bar p \to \phi\phi reaction

Since the $N^*(1535)$ resonance was found to have large coupling to the strangeness due to its possible large $s\bar s$ component, we investigate the possible contribution of the t-channel $N^*(1535)$ exchange for the $p\bar p \to \phi\phi$ reaction. Our calculation indicates that the new mechanism gives very significant contribution for the energies above 2.25 GeV and may be an important source for evading the Okubo-Zweig-Iizuka rule in the $\phi$ production from $N \bar{N}$ annihilation.Comment: 6 pages, 3 figure

The Near-Threshold Production of Phi Mesons in pp Collisions

The pp->pp phi reaction has been studied at the Cooler Synchrotron COSY-Juelich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S-wave dominance as well as a noticeable effect due to the proton-proton final state interaction. Taken together with data for pp omega-production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.Comment: 4 Pages, 3 Figures, 1 Table, submitted to Phys. Rev. Let

Hadronic Probes of the Polarized Intrinsic Strangeness of the Nucleon

We have previously interpreted the various large apparent violations of the naive Okubo-Zweig-Iizuka (OZI) rule found in many channels in $\bar{p}p$ annihilation at LEAR as evidence for an intrinsic polarized $\bar{s}s$ component of the nucleon wave function. The model is further supported by new data from LEAR and elsewhere. Here we discuss in more detail the possible form of the $\bar{s}s$ component of the nucleon wave function, interpret the new data and clarify the relative roles of strangeness shake-out and rearrangement, discuss whether alternative interpretations are still allowed by the new data, and propose more tests of the model.Comment: LaTeX, 31 page

Today's View on Strangeness

There are several different experimental indications, such as the pion-nucleon sigma term and polarized deep-inelastic scattering, which suggest that the nucleon wave function contains a hidden s bar s component. This is expected in chiral soliton models, which also predicted the existence of new exotic baryons that may recently have been observed. Another hint of hidden strangeness in the nucleon is provided by copious phi production in various N bar N annihilation channels, which may be due to evasions of the Okubo-Zweig-Iizuka rule. One way to probe the possible polarization of hidden s bar s pairs in the nucleon may be via Lambda polarization in deep-inelastic scattering.Comment: 8 pages LaTeX, 10 figures, to appear in the Proceedings of the International Conference on Parity Violation and Hadronic Structure, Grenoble, June 200

Okubo-Zweig-Iizuka-rule violation and B\to \eta^{(\prime)}K branching ratios

We show that few-percent Okubo-Zweig-Iizuka-rule violating effects in the quark-flavor basis for the $\eta$-$\eta'$ mixing can enhance the chiral scale associated with the $\eta_q$ meson few times. This enhancement is sufficient for accommodating the dramatically different data of the $B\to\eta^{\prime} K$ and $B\to\eta K$ branching ratios. We comment on other proposals for resolving this problem, including flavor-singlet contributions, axial U(1) anomaly, and nonperturbative charming penguins. Discrimination of the above proposals by means of the $B\to\eta^{(\prime)}\ell\nu$ and $B_s\to\eta^{(\prime)}\ell\ell$ data is suggested.Comment: 7 pages, 2 figures, discussion on B\to\eta^{(\prime)}K* added, more references adde