[en] The author gives a review about experimental results concerning the e⁺e^- annihilation into J/psi and psi'. In these experiments the quantum numbers and the decay modes of these particles are determined. Furthermore charmed mesons, tau particles, and upsilon resonances are discussed. In addition the e⁺e^- storage rings are described. (HSI)

[en] An overview is presented of the present status, future trends and applications of particle accelerators (CERN) and colliders (HERA) and particle detectors (H1-HERA), in basic research in physics in the world

[en] The discussions in the working group on diffractive processes were structured according to a scheme, in which first the experimental basis was specified followed by a presentation of theoretical papers and a general exchange of views on diffractive phenomena. Since diffraction is observed in many different channels, a common session was organised with participants from other working groups, in particular from the photoproduction and DIS community. A total of about 20 individual contributions were presented including those of the common discussion. Not all of them will be included in the proceedings. Some speakers had contributions to different sessions and submitted only one summary paper, others presented ideas for future analysis and are still working and others were too busy to finish the write up before the deadline. Diffractive phenomena observed at HERA were presented by T. Greenshaw of H1 and T. Docker from the ZEUS collaboration. The DO results on diffraction may be looked up in G. Forden's contribution to the proceedings. Further experimental results relevant to the topic ran be found in papers by M. Costa and S. Levonian issued in the photoproduction subsection. Experimentally it is not always easy to identify diffractive processes because pion and ordinary Regge exchange contributions are also present. This question is addressed in G. Levman's paper. New ideas to exploit a similarity between gluon - and Pomeron exchange were discussed by H. Kowalski, and G. Knies proposed a thrust analysis for diffractive events. In both cases work is going on which is not yet ready for a publication. (i. Ingelman reviewed existing Mt. Carlo programs on diffractive processes like POMPYT, RAPGAP and a program based on the Nikolaev - Zakharov approach to diffraction. These programs are well documented and need no further description in these proceedings. The same argument applies to V. Fadins talk, who reviewed published results on higher order corrections to the BFKL Pomeron. The other contributions to the diffractive working group, which are included in the proceedings, refer to the coherent Pomeron and hard diffractive processes in QCD involving a coherent Pomeron by M. Strikman and L. Frankfurt, respectively. Furthermore N.N. Nikolaev introduced a dipole picture to describe deep inelastic processes, and J. Bartels presented a perturbative approach to diffraction dissociation

[en] A search for the lepton flavour violating processes ep→μX and ep→τX is performed with the H1 experiment at HERA. Final states with a muon or tau and a hadronic jet are searched for in a data sample corresponding to an integrated luminosity of 66.5 pb^-1 for e⁺p collisions and 13.7 pb^-1 for e^-p collisions at a centre-of-mass energy of 319 GeV. No evidence for lepton flavour violation is found. Limits are derived on the mass and the couplings of leptoquarks inducing lepton flavour violation in an extension of the Buchmueller-Rueckl-Wyler effective model. Leptoquarks produced in ep collisions with a coupling strength of λ=0.3 and decaying with the same coupling strength to a muon-quark pair or a tau-quark pair are excluded at 95% confidence level up to masses of 459 GeV and 379 GeV, respectively. (orig.)

[en] The range of physics problems for which a detector emphasizing neutrals is most suitable is discussed. The primary goals are the all neutrals cross section, sigma/sub o/ (e⁺e^- → neutrals), the characterization of the neutral energy in multi-hadronic events, the search for monoenergetic photons, and good sensitivity in the difficult region of low energy photons. Those features of multi-hadronic events which are most relevant to a neutral detector were calculated using a jet model with parameters extrapolated from SPEAR energies. These distributions are presented and discussed

[en] A search for narrow baryonic resonances decaying into Ξ^-π^- or Ξ^-π⁺ and their antiparticles is carried out with the H1 detector using deep inelastic scattering events at HERA in the range of negative photon four-momentum transfer squared 2< Q²<100 GeV². No signal is observed for a new baryonic state in the mass range 1600-2300 MeV in either the doubly charged or the neutral decay channels. The known Ξ(1530)⁰ is observed through its decay mode into Ξ^-π⁺. Upper limits are given on the ratio of the production rates of new baryonic states, such as the hypothetical pentaquark states Ξ^-_5q or Ξ⁰_5q, relative to the Ξ(1530)⁰ baryon state. (orig.) 6

[en] The experimental contributions to the conference are summarised. New data, which are to a large extent still preliminary, were presented. An update on total cross sections for proton-proton scattering up to cosmic ray energies was given. The bulk of the data came, however, from lepton-proton scattering experiments, in particular from the new ep collider HERA at DESY operating in the 100 GeV c.m. energy range. Total cross sections for real and virtual photon-proton interactions are now available in a wide range of center of mass energies. It is observed that cross sections for virtual photons rise faster than the ones for real photons with increasing c.m. energy. Measurements of the photoproduction cross sections for vector mesons and the observation of rapidity gap events in deep inelastic lepton scattering introduce new aspects into the interpretation of diffractive processes and will contribute to a better understanding of the pomeron. A remarkable similarity between hadronic processes and photoproduction is observed when comparing the energy flow in the central rapidity region, which supports the universality of were parton interactions. New data on the partonic structure of the proton and the spin structure of the nucleon were also discussed in this conference. (author)

[en] The apparatus of the DESY-Heidelberg group is described. Preliminary results of a recent data evaluation are presented. In the investigation of the two photon cascade psi'(3.7) → γ + P/sub c/, P/sub c/ → γ + J/psi(3.1), about 60 events are found with J/psi → μ⁺μ^- or e⁺e^-. The angular distributions of the γ-rays with respect to the beam axis indicate that the intermediate state P/sub c/ has nonzero spin and the mass M(P/sub c/) = (3.51 +- 0.02) GeV, while the solution M(P/sub c/) = 3.26 GeV seems to be excluded. From a study of total neutral decays of J/psi(3.1) an upper limit of 1.2 percent for the neutral radiative decays is obtained

[en] A search for heavy flavour production has been made by investigating the reaction e⁺e^- → multihadrons at centre of mass energies of up to 35 GeV. No indication has been seen for the production of top mesons. Upper limits for the production of free charge 2/3 quarks have been derived from a dE/dx measurement and are of the order of 0.1. sigmasub(μμ). Upper limits for the lifetime of B-mesons of about 10^-9 sec are also obtained. A measurement of the neutral energy fraction is reported

[en] The modifications to the SPEAR version of the Crystal Ball required by the higher energies at PEP are discussed. Since the hadron multiplicity is expected to rise as log s, their average energy must rise. On the other hand, if the hadrons are produced in jets, the low energy part of their spectrum is not heavily depleted. This implies that modifications for high energy particles should not deteriorate low energy performance. An external iron calorimeter for measuring the high energy hadrons, charged and neutral, is considered. To improve the angular resolution on γ's, an active internal converter has been studied, estimates have been made of its expected performance, and difficulties requiring further study have been outlined