Kaon-Nucleon Scattering Amplitudes and Z∗^*-Enhancements from Quark Born Diagrams

We derive closed form kaon-nucleon scattering amplitudes using the ``quark Born diagram" formalism, which describes the scattering as a single interaction (here the OGE spin-spin term) followed by quark line rearrangement. The low energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with experiment given conventional quark model parameters. For $k_{lab}> 0.7$ Gev however the I=1 elastic phase shift is larger than predicted by Gaussian wavefunctions, and we suggest possible reasons for this discrepancy. Equivalent low energy KN potentials for S-wave scattering are also derived. Finally we consider OGE forces in the related channels K$\Delta$, K$^*$N and K$^*\Delta$, and determine which have attractive interactions and might therefore exhibit strong threshold enhancements or ``Z$^*$-molecule" meson-baryon bound states. We find that the minimum-spin, minimum-isospin channels and two additional K$^*\Delta$ channels are most conducive to the formation of bound states. Related interesting topics for future experimental and theoretical studies of KN interactions are also discussed.Comment: 34 pages, figures available from the authors, revte

A search for doubly charged higgs production in z0 decays

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Search for a scalar top quark using the OPAL detector

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Friendship and organizational analysis: toward a research agenda

Recent developments in organizational analysis have done much to fill out the dry, textbook image of rational,formal structures, Yet on one of the commonest kinds of organizational experience-friendship-organizational analysis has remained virtually silent. By contrast, within the wider social science literature some writers have recently accorded greater importance to friendship as a social phenomenon. This article suggests that organizational analysis would be well served by doing the same. To this end, the article explores what this might entail and identifies some of the issues that it could illuminate, both empirically and theoretically. In particular, it presents friendship as a folk concept, which recognizes the situational variability of its form, experience, and connectedness with other forms of relationship. In doing so, the article will help define and open lip a focus for future research into friendship and organizational analysis