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Abstract:

A search for stable and long-lived heavy charged particles used the data taken by the DELPHI experiment at energies from 130 to 183 GeV. The Cherenkov light detected in the Ring Imaging Cherenkov Detector and the ionization loss measured in the Time Projection Chamber identify heavy particles from masses of 2 to nearly 89 GeV/c². Upper limits are given on the production cross-section and masses of sleptons, free squarks with a charge of q = ± 2/3e and hadronizing squarks. © 1998 Elsevier Science B.V. All rights reserved.

Abstract:

A ring-imaging Cherenkov detector, equipped with hybrid photon detectors, has been operated in a charged-particlc beam. Focussed ring images from various particle types were detected using silica aerogel, air and C4F10 gas radiators. The detector, a prototype for the CERN LHC-B experiment, is described and first observations are reported, © IWS Elsevier Science B.V. All rights reserved.

Abstract:

A search for the production of the η′c meson, the first radial excitation of the ground state of charmonium ηc(2980), in the photon-photon fusion reaction at LEP has been performed using the data collected by the DELPHI detector during 1992-1996. No evidence of η′c production is found in the mass region 3520-3800 MeV/c². An upper limit for the ratio of the two-photon widths of the η′c and ηc is obtained. © 1998 Published by Elsevier Science B.V. All rights reserved.

Abstract:

Two-particle angular correlations in jet cones have been measured in e⁺e^- annihilation into hadrons at LEP energies (√s =91 and 183 GeV) and are compared with QCD predictions using the LPHD hypothesis. Two different functions have been tested. While the differentially normalized correlation function shows substantial deviations from the predictions, a globally normalized correlation function agrees well. The size of a α^effS (and other QCD parameters) and its running with the relevant angular scale, the validity of LPHD, and problems due to non-perturbative effects are discussed critically. © 1998 Elsevier Science B.V. All rights reserved.

Abstract:

Decays of W^± bosons, produced at LEP2, have been used to measure the |Vcs| element of the Cabibbo-Kobayashi-Maskawa matrix. Values for |Vcs| were extracted both from the measured hadronic branching ratio of W^± decays and by tagging the flavour of hadronic jets produced in W^± decays. Applying the two methods to the data collected during 1996 at energies of 161 and 172 GeV, DELPHI obtains |Vcs| = 0.091^+0.15-0.14(stat) ± 0.05(syst). © 1998 Elsevier Science B.V. All rights reserved.