The process e + e − → γγ ( γ ) is studied using data recorded with the OPAL detector at LEP. The data sample corresponds to a total integrated luminosity of 56.2 pb − 1 taken at a centre-of-mass energy of 183 GeV. The measured cross-section agrees well with the expectation from QED. A fit to the angular distribution is used to obtain improved limits at 95% CL on the QED cut-off parameters: Λ + > 233 GeV and Λ − > 265 GeV as well as a mass limit for an excited electron, M e ∗ > 227 GeV assuming equal e ∗ e γ and ee γ couplings. No evidence for resonance production is found in the invariant mass spectrum of photon pairs. Limits are obtained for the cross-section times branching ratio for a resonance decaying into two photons.

Cross-sections and angular distributions for hadronic and lepton pair final states in e+e− collisions at a centre-of-mass energy near 189 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. The results are used to measure the energy dependence of the electromagnetic coupling constant αem, and to place limits on new physics as described by four-fermion contact interactions or by the exchange of a new heavy particle such as a sneutrino in supersymmetric theories with R-parity violation. A search for the indirect effects of the gravitational interaction in extra dimensions on the μ+μ− and τ+τ− final states is also presented. Submitted to European Journal of Physics C The OPAL Collaboration G.Abbiendi, K.Ackerstaff, G.Alexander, J. Allison, K.J.Anderson, S.Anderson, S.Arcelli, S.Asai, S.F.Ashby, D.Axen, G.Azuelos, A.H.Ball, E. Barberio, R.J. Barlow, J.R.Batley, S. Baumann, J. Bechtluft, T.Behnke, K.W.Bell, G.Bella, A.Bellerive, S. Bentvelsen, S. Bethke, S. Betts, O.Biebel, A.Biguzzi, I.J. Bloodworth, P. Bock, J. Böhme, O.Boeriu, D.Bonacorsi, M.Boutemeur, S. Braibant, P. Bright-Thomas, L. Brigliadori, R.M.Brown, H.J. Burckhart, P.Capiluppi, R.K.Carnegie, A.A.Carter, J.R.Carter, C.Y.Chang, D.G.Charlton, D.Chrisman, C.Ciocca, P.E.L.Clarke, E.Clay, I. Cohen, J.E.Conboy, O.C.Cooke, J. Couchman, C.Couyoumtzelis, R.L.Coxe, M.Cuffiani, S.Dado, G.M.Dallavalle, S.Dallison, R.Davis, S.De Jong, A. de Roeck, P.Dervan, K.Desch, B.Dienes, M.S.Dixit, M.Donkers, J.Dubbert, E.Duchovni, G.Duckeck, I.P.Duerdoth, P.G.Estabrooks, E. Etzion, F. Fabbri, A. Fanfani, M. Fanti, A.A. Faust, L. Feld, P. Ferrari, F. Fiedler, M. Fierro, I. Fleck, A. Frey, A. Fürtjes, D.I. Futyan, P.Gagnon, J.W.Gary, G.Gaycken, C.Geich-Gimbel, G.Giacomelli, P.Giacomelli, W.R.Gibson, D.M.Gingrich, D.Glenzinski, J.Goldberg, W.Gorn, C.Grandi, K.Graham, E.Gross, J.Grunhaus, M.Gruwé, C.Hajdu G.G.Hanson, M.Hansroul, M.Hapke, K.Harder, A.Harel, C.K.Hargrove, M.Harin-Dirac, M.Hauschild, C.M.Hawkes, R.Hawkings, R.J.Hemingway, G.Herten, R.D.Heuer, M.D.Hildreth, J.C.Hill, P.R.Hobson, A.Hocker, K.Hoffman, R.J.Homer, A.K.Honma, D.Horváth, K.R.Hossain, R.Howard, P.Hüntemeyer, P. Igo-Kemenes, D.C. Imrie, K. Ishii, F.R. Jacob, A. Jawahery, H. Jeremie, M. Jimack, C.R. Jones, P. Jovanovic, T.R. Junk, N.Kanaya, J.Kanzaki, D.Karlen, V.Kartvelishvili, K.Kawagoe, T.Kawamoto, P.I.Kayal, R.K.Keeler, R.G.Kellogg, B.W.Kennedy, D.H.Kim, A.Klier, T.Kobayashi, M.Kobel, T.P.Kokott, M.Kolrep, S.Komamiya, R.V.Kowalewski, T.Kress, P.Krieger, J. von Krogh, T.Kuhl, P.Kyberd, G.D. Lafferty, H. Landsman, D. Lanske, J. Lauber, I. Lawson, J.G. Layter, D. Lellouch, J. Letts, L. Levinson, R. Liebisch, J. Lillich, B. List, C. Littlewood, A.W.Lloyd, S.L. Lloyd, F.K. Loebinger, G.D. Long, M.J. Losty, J. Lu, J. Ludwig, D. Liu, A.Macchiolo, A.Macpherson, W.Mader, M.Mannelli, S.Marcellini, T.E.Marchant, A.J.Martin, J.P.Martin, G.Martinez, T.Mashimo, P.Mättig, W.J.McDonald, J.McKenna, E.A.Mckigney , T.J.McMahon, R.A.McPherson, F.Meijers, P.Mendez-Lorenzo, F.S.Merritt, H.Mes, I.Meyer, A.Michelini, S.Mihara, G.Mikenberg, D.J.Miller, W.Mohr, A.Montanari, T.Mori, K.Nagai, I. Nakamura, H.A.Neal, R.Nisius, S.W.O’Neale, F.G.Oakham, F.Odorici, H.O.Ogren, A.Okpara, M.J.Oreglia, S.Orito, G. Pásztor, J.R. Pater, G.N.Patrick, J. Patt, R. Perez-Ochoa, S. Petzold, P. Pfeifenschneider , J.E. Pilcher, J. Pinfold, D.E. Plane, P. Poffenberger, B. Poli, J. Polok, M.Przybycień, A.Quadt, C.Rembser, H.Rick, S. Robertson, S.A.Robins, N.Rodning, J.M.Roney, S. Rosati, K.Roscoe, A.M.Rossi, Y.Rozen, K.Runge, O.Runolfsson, D.R.Rust, K. Sachs, T. Saeki, O. Sahr, W.M. Sang, E.K.G. Sarkisyan, C. Sbarra, A.D. Schaile, O. Schaile, P. Scharff-Hansen, J. Schieck, S. Schmitt, A. Schöning, M. Schröder, M. Schumacher, C. Schwick, W.G. Scott, R. Seuster, T.G. Shears, B.C. Shen, C.H. Shepherd-Themistocleous , P. Sherwood, G.P. Siroli, A. Skuja, A.M. Smith, G.A. Snow, R. Sobie, S. Söldner-Rembold , S. Spagnolo, M. Sproston, A. Stahl, K. Stephens, K. Stoll, D. Strom, R. Ströhmer, B. Surrow, S.D.Talbot, P.Taras,

The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons has been studied using data taken at √ see = 183GeV and 189GeV with the OPAL detector at LEP. Results are presented for pp̄ invariant masses, W , in the range 2.15 < W < 3.95GeV. The cross-section measurements are compared with previous data and with recent analytic calculations based on the quark-diquark model. (To be submitted to Eur. Phys. J. C.) The OPAL Collaboration G.Abbiendi, C.Ainsley, P.F. Åkesson, G.Alexander, J. Allison, P.Amaral, G.Anagnostou, K.J.Anderson, S.Arcelli, S.Asai, D.Axen, G.Azuelos, I. Bailey, E. Barberio, T.Barillari, R.J. Barlow, R.J. Batley, P. Bechtle, T.Behnke, K.W.Bell, P.J. Bell, G.Bella, A.Bellerive, G.Benelli, S. Bethke, O.Biebel, I.J. Bloodworth, O.Boeriu, P. Bock, D.Bonacorsi, M.Boutemeur, S. Braibant, L. Brigliadori, R.M.Brown, K.Buesser, H.J. Burckhart, S. Campana, R.K.Carnegie, B.Caron, A.A.Carter, J.R.Carter, C.Y.Chang, D.G.Charlton, A.Csilling , M.Cuffiani, S.Dado, G.M.Dallavalle, S.Dallison, A.De Roeck, E.A.De Wolf, K.Desch, B.Dienes, M.Donkers, J.Dubbert, E.Duchovni, G.Duckeck, I.P.Duerdoth, E. Elfgren, E. Etzion, F. Fabbri, L. Feld, P. Ferrari, F. Fiedler, I. Fleck, M. Ford, A. Frey, A. Fürtjes, P.Gagnon, J.W.Gary, G.Gaycken, C.Geich-Gimbel, G.Giacomelli, P.Giacomelli, M.Giunta, J.Goldberg, E.Gross, J.Grunhaus, M.Gruwé, P.O.Günther, A.Gupta, C.Hajdu, M.Hamann, G.G.Hanson, K.Harder, A.Harel, M.Harin-Dirac, M.Hauschild, J. Hauschildt, C.M.Hawkes, R.Hawkings, R.J.Hemingway, C.Hensel, G.Herten, R.D.Heuer, J.C.Hill, K.Hoffman, R.J.Homer, D.Horváth, R.Howard, P.Hüntemeyer, P. Igo-Kemenes, K. Ishii, H. Jeremie, P. Jovanovic, T.R. Junk, N.Kanaya, J.Kanzaki, G.Karapetian, D.Karlen, V.Kartvelishvili, K.Kawagoe, T.Kawamoto, R.K.Keeler, R.G.Kellogg, B.W.Kennedy, D.H.Kim, K.Klein, A.Klier, S.Kluth, T.Kobayashi, M.Kobel, S.Komamiya, L.Kormos, R.V.Kowalewski, T.Krämer, T.Kress, P.Krieger, J. von Krogh, D.Krop, K.Kruger, M.Kupper, G.D. Lafferty, H. Landsman, D. Lanske, J.G. Layter, A. Leins, D. Lellouch, J. Letts, L. Levinson, J. Lillich, S.L. Lloyd, F.K. Loebinger, J. Lu, J. Ludwig, A.Macpherson, W.Mader, S.Marcellini, T.E.Marchant, A.J.Martin, J.P.Martin, G.Masetti, T.Mashimo, P.Mättig, W.J.McDonald, J.McKenna, T.J.McMahon, R.A.McPherson, F.Meijers, P.Mendez-Lorenzo, W.Menges, F.S.Merritt, H.Mes, A.Michelini, S.Mihara, G.Mikenberg, D.J.Miller, S.Moed, W.Mohr, T.Mori, A.Mutter, K.Nagai, I. Nakamura, H.A.Neal, R.Nisius, S.W.O’Neale, A.Oh, A.Okpara, M.J.Oreglia, S.Orito, C. Pahl, G. Pásztor, J.R. Pater, G.N.Patrick, J.E. Pilcher, J. Pinfold, D.E. Plane, B. Poli, J. Polok, O. Pooth, M.Przybycień, A.Quadt, K.Rabbertz, C.Rembser, P.Renkel, H.Rick, J.M.Roney, S. Rosati, Y.Rozen, K.Runge, K. Sachs, T. Saeki, O. Sahr, E.K.G. Sarkisyan , A.D. Schaile, O. Schaile, P. Scharff-Hansen, J. Schieck, T. Schoerner-Sadenius, M. Schröder, M. Schumacher, C. Schwick, W.G. Scott, R. Seuster , T.G. Shears, B.C. Shen, C.H. Shepherd-Themistocleous , P. Sherwood, G. Siroli, A. Skuja, A.M. Smith, R. Sobie, S. Söldner-Rembold, S. Spagnolo, F. Spano, A. Stahl, K. Stephens, D. Strom, R. Ströhmer, S. Tarem, M.Tasevsky , R.J. Taylor, R.Teuscher, M.A.Thomson, E.Torrence, D.Toya, P.Tran, T.Trefzger, A.Tricoli, I. Trigger, Z. Trócsányi, E.Tsur, M.F.Turner-Watson, I. Ueda, B.Ujvári, B.Vachon, C.F.Vollmer, P.Vannerem, M.Verzocchi, H.Voss, J. Vossebeld, D.Waller, C.P.Ward, D.R.Ward, P.M.Watkins, A.T.Watson, N.K.Watson, P.S.Wells, T.Wengler, N.Wermes, D.Wetterling G.W.Wilson, J.A.Wilson, G.Wolf, T.R.Wyatt, S.Yamashita, D. Zer-Zion, L. Zivkovic

The product ion rate o f electrons with momentum p > 4 G e V / c and large m o m e n t u m transverse to the jet containing the electron has been measured in 136 000 hadronic decays o f the Z ~ recorded with the O P A L detector at LEP in 1990. The dominan t source o f these electrons is the semileptonic decay of hadrons containing b quarks. I f we assume that the semileptonic branching fraction o f b hadrons produced on the Z ~ resonance is the same as the branching fraction measured at the r ( 4 S) resonance, we determine Fse = 394 + 13 + 32 MeV, where the first error is statistical and the second error is systematic. The sensitivity o f the result to this assumption is discussed. We have reduced the dependence o f our result on the model o f b hadron semileptonic decay by taking into account the correlat ion between the model dependence o f the branching fractions measured at the Y (4 S ) and of our kinematic acceptance for electrons.

We present measurements of triple gauge boson coupling parameters using data recorded by the OPAL detector at LEP2 at a centre-of-mass energy of 172 GeV. A total of 120 W-pair candidates has been selected in the qqqq, qq ℓν ℓ and ℓν ℓ ℓ ′ ν ℓ ′ decay channels, for an integrated luminosity of 10.4 pb − 1 . We use these data to determine several different anomalous coupling parameters using the measured cross-section and the distributions of kinematic variables. We measure α Bφ =0 . 35 +1 . 29 − 1 . 07 ± 0 . 38, α Wφ =0 . 00 +0 . 30 − 0 . 28 ± 0 . 11, α W =0 . 18 +0 . 49 − 0 . 47 ± 0 . 23, ∆ g z1 = − 0 . 03 +0 . 40 − 0 . 37 ± 0 . 14, ∆ κ ( HISZ ) γ =0 . 03 +0 . 55 − 0 . 51 ± 0 . 20, and ∆ κ =0 . 03 +0 . 49 − 0 . 46 ± 0 . 21. Combining the α Wφ result with our previous result obtained from the 161 GeV data sample we measure α Wφ = − 0 . 08 +0 . 28 − 0 . 25 ± 0 . 10. All of these measurements are consistent with the Standard Model.

A search is described to detect charged Higgs bosons via the process e + e − → H + H − , using data collected by the OPAL detector at center-of-mass energies of 130 − 172 GeV with a total integrated luminosity of 25 pb − 1 . The decay channels are assumed to be H + → qq ′ and H + → τ + ν τ . No evidence for charged Higgs boson production is observed. The lower limit for its mass is determined to be 52 GeV at 95% confidence level, independent of the H + → τ + ν τ branching ratio. dashes indicate masses which are kinematically forbidden or not simulated. Note that there is significant overlap between the various M H ± -dependent selections.

The short hard gamma ray burst (SHB) 170817A that followed GW170817A, the first neutron stars merger (NSM) detected in gravitational waves (GWs), has shown beyond doubt that NSMs produce beamed SHBs. Its low luminosity and other properties that differ from those of ordinary SHBs were predicted by the cannonball model of gamma ray bursts. Low luminosity (LL) SHBs are mainly ordinary SHBs viewed far off-axis. They are produced mainly by nearby NSMs. Because of beaming, most of the NSMs, including those within the current horizon of Ligo-Virgo, produce SHBs most of which are invisible from Earth. But, their pulsar wind nebula powered by the spin down of the remnant neutron star produces an early-time isotropic afterglow with a universal temporal shape. This smoking gun of NSMs is detectable independent of whether the SHB was visible, or was invisible from Earth because of being beamed away.

A search for charginos and neutralinos, predicted by supersymmetric theories, has been performed using a data sample of 57 pb−1 at centre-of-mass energies of 181–184 GeV taken with the OPAL detector at LEP. No evidence for chargino or neutralino production has been found. Upper limits on chargino and neutralino pair production (χ̃1 χ̃ − 1 ,χ̃ 0 1χ̃ 0 2) crosssections are obtained as a function of the chargino mass χ̃1 ), the lightest neutralino mass χ̃1 ) and the second lightest neutralino mass χ̃2 ). For large chargino masses the limits have been improved with respect to the previous analyses at lower centre-ofmass energies. Exclusion regions at 95% confidence level (C.L.) of parameters of the Constrained Minimal Supersymmetric Standard Model are determined for the case of a large universal scalar mass, m0, implying heavy scalar fermions, and for the case of a small m0 resulting in light scalar fermions and giving the worst-case limits. Within this framework and for χ̃1 − χ̃01 ≥ 5 GeV the 95% C.L. lower limits on χ̃1 for m0 = 500 GeV are 90.0 and 90.2 GeV for tan β = 1.5 and 35 respectively. These limits for all m0 (the worst-case) are 69.1 and 65.2 GeV for tan β = 1.5 and 35 respectively. Exclusion regions are also presented for neutralino masses, including an absolute lower limit at 95% C.L. for the mass of the lightest neutralino of 30.1 GeV for m0 = 500 GeV (24.2 GeV for all m0), with implications for experimental searches for the lightest neutralino as a dark matter candidate. Submitted to Eur. Phys. Journal C G. Abbiendi, K. Ackerstaff, G. Alexander, J. Allison, N. Altekamp, K.J. Anderson, S. Anderson, S. Arcelli, S. Asai, S.F. Ashby, D. Axen, G. Azuelos, A.H. Ball, E. Barberio, R.J. Barlow, R. Bartoldus, J.R. Batley, S. Baumann, J. Bechtluft, T. Behnke, K.W. Bell, G. Bella, A. Bellerive, S. Bentvelsen, S. Bethke, S. Betts, O. Biebel, A. Biguzzi, S.D. Bird, V. Blobel, I.J. Bloodworth, M. Bobinski, P. Bock, J. Böhme, D. Bonacorsi, M. Boutemeur, S. Braibant, P. Bright-Thomas, L. Brigliadori, R.M. Brown, H.J. Burckhart, C. Burgard, R. Bürgin, P. Capiluppi, R.K. Carnegie, A.A. Carter, J.R. Carter, C.Y. Chang, D.G. Charlton, D. Chrisman, C. Ciocca, P.E.L. Clarke, E. Clay, I. Cohen, J.E. Conboy, O.C. Cooke, C. Couyoumtzelis , R.L. Coxe, M. Cuffiani, S. Dado, G.M. Dallavalle, R. Davis, S. De Jong, L.A. del Pozo, A. de Roeck, K. Desch, B. Dienes, M.S. Dixit, J. Dubbert, E. Duchovni, G. Duckeck, I.P. Duerdoth, D. Eatough, P.G. Estabrooks, E. Etzion, H.G. Evans, F. Fabbri, M. Fanti, A.A. Faust, F. Fiedler, M. Fierro, I. Fleck, R. Folman, A. Fürtjes, D.I. Futyan, P. Gagnon, J.W. Gary, J. Gascon, S.M. Gascon-Shotkin, G. Gaycken, C. Geich-Gimbel, G. Giacomelli, P. Giacomelli, V. Gibson, W.R. Gibson, D.M. Gingrich, D. Glenzinski, J. Goldberg, W. Gorn, C. Grandi, E. Gross, J. Grunhaus, M. Gruwé, G.G. Hanson, M. Hansroul, M. Hapke, K. Harder, C.K. Hargrove, C. Hartmann, M. Hauschild, C.M. Hawkes, R. Hawkings, R.J. Hemingway, M. Herndon, G. Herten, R.D. Heuer, M.D. Hildreth, J.C. Hill, S.J. Hillier, P.R. Hobson, A. Hocker, R.J. Homer, A.K. Honma, D. Horváth, K.R. Hossain, R. Howard, P. Hüntemeyer, P. Igo-Kemenes, D.C. Imrie, K. Ishii, F.R. Jacob, A. Jawahery, H. Jeremie, M. Jimack, C.R. Jones, P. Jovanovic, T.R. Junk, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, P.I. Kayal, R.K. Keeler, R.G. Kellogg, B.W. Kennedy, A. Klier, S. Kluth, T. Kobayashi, M. Kobel, D.S. Koetke, T.P. Kokott, M. Kolrep, S. Komamiya, R.V. Kowalewski, T. Kress, P. Krieger, J. von Krogh, T. Kuhl, P. Kyberd, G.D. Lafferty, D. Lanske, J. Lauber, S.R. Lautenschlager, I. Lawson, J.G. Layter, D. Lazic, A.M. Lee, D. Lellouch, J. Letts, L. Levinson, R. Liebisch, B. List, C. Littlewood, A.W. Lloyd, S.L. Lloyd, F.K. Loebinger, G.D. Long, M.J. Losty, J. Ludwig, D. Liu, A. Macchiolo, A. Macpherson, W. Mader, M. Mannelli, S. Marcellini, C. Markopoulos, A.J. Martin, J.P. Martin, G. Martinez, T. Mashimo, P. Mättig, W.J. McDonald, J. McKenna, E.A. Mckigney, T.J. McMahon, R.A. McPherson, F. Meijers, S. Menke, F.S. Merritt, H. Mes, J. Meyer, A. Michelini, S. Mihara, G. Mikenberg, D.J. Miller, R. Mir, W. Mohr, A. Montanari, T. Mori, K. Nagai, I. Nakamura, H.A. Neal, B. Nellen, R. Nisius, S.W. O’Neale, F.G. Oakham, F. Odorici, H.O. Ogren, M.J. Oreglia, S. Orito, J. Pálinkás, G. Pásztor, J.R. Pater, G.N. Patrick, J. Patt, R. Perez-Ochoa, S. Petzold, P. Pfeifenschneider, J.E. Pilcher, J. Pinfold, D.E. Plane, P. Poffenberger, J. Polok, M. Przybycień, C. Rembser, H. Rick, S. Robertson, S.A. Robins, N. Rodning, J.M. Roney, K. Roscoe, A.M. Rossi, Y. Rozen, K. Runge, O. Runolfsson, D.R. Rust, K. Sachs, T. Saeki, O. Sahr, W.M. Sang, E.K.G. Sarkisyan, C. Sbarra, A.D. Schaile, O. Schaile, F. Scharf, P. Scharff-Hansen, J. Schieck, B. Schmitt, S. Schmitt, A. Schöning, M. Schröder, M. Schumacher, C. Schwick , W.G. Scott, R. Seuster, T.G. Shears, B.C. Shen, C.H. Shepherd-Themistocleous , P. Sherwood, G.P. Siroli, A. Sittler, A. Skuja, A.M. Smith, G.A. Snow, R. Sobie, S. Söldner-Rembold, M. Sproston, A. Stahl, K. Stephens, J. Steuerer, K. Stoll, D. Strom, R. Ströhmer, B. Surrow, S.D. Talbot, S. Tanaka, P. Taras, S. Tarem, R. Teuscher, M. Thiergen, M.A. Thomson, E. von Törne, E. Torrence, S. Towers, I. Trigger, Z. Trócsányi,

Results are presented on the production of excited charm and excited charm-strange mesons in hadronic Z0 decays. The results are obtained from approximately 4.3 million hadronic Z0 decays, collected on or near the Z0 resonance using the OPAL detector at LEP. The D~(2420) and D2°(2460) mesons are reconstructed in the n•+"final state and their separate production rates in charm fragmentation and in weak decays of bhadrons are determined. From these measurements, the charm hadronization fractions and the inclusive branching ratios ofb-hadrons to these neutral P-wave charm mesons are determined to be f(cD~) f(c-D2°) f(bD~) f(bD2°) 0.021 ± 0.007( stat) ± 0.003( syst ), 0.052 ± 0.022(stat) ± 0.013( syst ), 0.050 ± 0.014(stat) ± 0.006(syst), 0.04 7 ± 0.024(stat) ± 0.013( syst ). We also present the first observation at LEP of the D;i (2536) meson which is reconstructed in both the D*+K~ and D*°K+ final states. After correcting for the expected contribution from bb events, these results are used to derive the charm hadronization fraction f( c ~ D;i): f(c ~ D;i) = 0.016 ± 0.004(stat) ± 0.003(syst). (To be submitted to Zeitschrift fiir Physik C) The OPAL Collaboration K. Ackersta:ffS, G. Alexander23 , J. Allison16 , N. Altekamp5 , K.J. Anderson9 , S. Anderson12 , S.Arcell?, S.Asai , D.Axen 29 , G.Azuelos18·a, A.H.BalF 7 , E.Barberio , R.J.Barlow , R.Bartoldus3 , J.R.Batley5 , S.Baumann3 , J.Bechtluft1\ C.Beeston , T.Behnke , A.N.BelF, K.W. Bell20 , G. Bella , S. Bentvelsen , P. Berlich , S. Bethke1\ 0. BiebeF\ A. Biguzzi5 , S.D. Bird16 , V. BlobeJ2 , I.J. Bloodworth1 , J .E. Bloomer , M. Bobinski , P. BocPl, D. Bonacors?, M. Boutemeur3\ B.T. Bouwens , S. Braibant , L. Brigliador?, R.M. Brown , H.J. Burckhart8 , C. Burgard8 , R. Biirgin10 , P. Capilupp?, R.K. Carnegie6 , A.A. Carter13, J.R. Carter5 , C.Y. Chang17 , D.G. Charlton1•b, D. Chrisman\ P.E.L. Clarke15 , I. Cohen23 , J.E.Conboy15 , O.C.Cooke16 , M.Cuffian?, S.Dado , C.Dallapiccola , G.M.Dallavalle , S.De Jong , L.A. del Pozo\ K.Desch , M.S.Dixit 7 , E. do Couto e Silva , M.Doucet , E. Duchovn?6 , G. Duckeck\ I.P. Duerdoth , D. Eatough , J.E.G. Edwards , P.G. Estabrooks6 , H.G. Evans9 , M. Evans13 , F. Fabbr?, M. Fanti2 , A.A. Faust30 , F. Fiedler27 , M. Fierro , H.M. Fischer\ I. Fleck , R. Folman , D.G. Fong , M. Foucher , A. Fiirtjes , D.I. Futyan16, P. Gagnon', J.W. Gary\ J. Gascon , S.M. Gascon-Shotkin17 , N.I. Geddes 20 , C. Geich-Gimbel , T. Geralis20 , G. Giacomelli , P. Giacomelli , R. Giacomell?, V. Gibson , W.R.Gibson13 , D.M.Gingrich30·", D.Glenzinski , J.Goldberg , M.J.Goodrick , W.Gorn\ C.Grandi2 , E.Gross 26 , J.Grunhaus 23 , M.Gruwe , C.Hajdu32 , G.G.Hanson , M.Hansroul8 , M. Hapke13 , C.K. Hargrove , P.A. Hart , C. Hartmann , M. Hauschild , C.M. Hawkes", R.Hawkings27 , R.J.Hemingway , M.Herndon, G.Herten, R.D.Heuer , M.D.Hildreth , J .C. HillS, S.J. Hillier1 , T. Hilse10 , P.R. Hobson25 , R.J. Homer\ A.K. Honma28·", D. Horvath ·c, R. Howard29 , D.E. Hutchcroft5 , P. Igo-Kemenes , D.C. Imrie , M.R. Ingram , K. Ishii\ A.Jawahery17 , P.W.Jeffreys20 , H.Jeremie, M.Jimackl, A.Joly , C.R.Jones , G.Jones , M.Jones6 , U.Jost11, P.Jovanovic , T.R.Junk", D.Karlen6 , V.Kartvelishvili , K.Kawagoe\ T. Kawamoto2\ R.K. Keeler28 , R.G. Kellogg , B.W. Kennedy, J. Kirk , A. Klier , S. Kluth8 , T. Kobayash?\ M. KobeF0 , D.S. Koetke , T.P. Kokotts, M. Kolrep , S. Komamiya2\ T. Kress 11 , P. Krieger6 , J. von Krogh1 \ P. Kyberds, G.D. Lafferty , R. Lahmann17 , W.P. Lai19 , D. Lanske1\ J. Lauber15 , S.R. Lautenschlagers\ J.G. Layter\ D.Lazic22 , A.M.Lee31, E.Lefebvre18 , D.Lellouch , J.Letts12 , L.Levinson , S.L.Lloyds, F .K. Loebinger16 , G.D. Long28 , M.J. Losty7 , J. Ludwig10 , A. Macchiolo , A. Macpherson so, M. Mannelli8 , S. Marcellini2 , C. Markuss, A.J. Martin1s, J.P. Martin18 , G. Martinez , T. Mashimo2\ P. Miittigs, W.J. McDonald , J. McKenna , E.A. Mckigney, T.J. McMahon\ R.A. McPherson8 , F. Meijers8 , S. Menkes, F.S. Merritt9 , H. Mes7 , J. Meyer27, A. Michelin?, G. Mikenberg26 , D.J. Miller15 , A. Mincer22·e, R. Mir , W. Mohr10 , A. Montanari , T. Mor?\ M.Morii2\ U.Miillers, K.Nagai26 , I.Nakamura\ H.A.Neal , B.Nellen , R.Nisius , S.W. O'Neale\ F.G. Oakham , F. Odorici , H.O. Ogren , N.J. Oldershaw , M.J. Oreglia , S.Orito2\ J.Palinkas33·d, G.Pasztor32 , J.R.Pater16 , G.N.Patrick , J.Patt10 , M.J.Pearcel, S. Petzold27 , P. Pfeifenschneider14 , J .E. Pilcher9 , J. Pinfold , D.E. Plane , P. Poffenberger , B.Poli , A.Posthaus , H.Przysiezniak , D.L.Rees\ D. Rigby\ S.Robertson , S.A.Robins , N. Rodning , J.M. Roney, A. Rooke , E. Ros , A.M. Rossi', M. Rosvick , P. Routenburg , Y. Rozen22 , K. Runge10 , 0. Runolfsson8 , U. Ruppel\ D.R. Rust , R. Rylko , K. Sachs , T. Saeki2\ E.K.G. Sarkisyan2S, C. Sbarra29 , A.D. Schailes\ 0. Schaile\ F. Scharf\ P. Scharff-Hansen8 , P. Schenk3\ J. Schieck11 , P. Schleper11 , B. Schmitt , S. Schmitt ,

The cross section of the pure QED process e+ e-> "/"/ has been measured using data accumulated during the 1989 and 1990 scans of the Z resonance at LEP. Both the energy dependence and the angular distribution are in good agreement with the QED prediction, Upper limits on the branching ratios of Z -> "f"f, Z -> 1r "f and Z -> rn have been set at lAx I o-4 , 1 Ax 10-'1 and 2.0 x 10-4 respectively. Lower limits on the cutoff parameters of the modified electron propagator have been found to be A+> 117 GeV and A_ > 110 GeV. The reaction e+e-> "/"1"1 has also been studied and was found to be consistent with the QED prediction_ An upper limit on the branching ratio of Z _,"/"/"/has been set at 6 .. 6 x 10• All the limits are given at 95% confidence leveL (Submitted to Physics Letters D) The OPAL Collaboration lii.Z. Akrawy 12 , G. Alexander22 , J. Allison 15 , P.P. Allport5 , K.J. Anderson9 , J.C. Armitage6 , G.T.J. Arnison 9, P. Ashton15 , G. Azuelos·d, J.T.l\I. Baines15 , A. H. Ball 16 , J. Banks15 , G.J. Barker , R.J. Barlow 15 , .I.R. Batley5 , G. Beaudoin'\ A. Beck 22 , J. Becker10 , T. Behnkes, K.W. Bell' 9 , G. Bella22 , S. Bethken, 0. Bicbel , U. Binder 10 , I.J. Bloodworth', P. Bockn, II. Breukers, R.l\1. Brown 19 , R. Bruns, A. Buijss, H.J. Burckharts, P. Capiluppi2 , R. K. Carncgie , A.A. Carler12 , J .R. Carter5 , C.Y. Chang16 , D.G. Charltons, J .T.l\1. Chrin 15 , P.E.L. Clarkc , I. Cohen , W.J. Collins , J .E. Conboy14 , i\1. Couch , 1\l. Coupland , 1\l. Cuffiani , S. Dado21 , G.l\1. Dallamlle , S. De Jongs, P. Dcbu20 , 1\l.l\l. Deninno , A. Dieckmann ll, 1\l. Dittmar', 1\l.S. Dixit 1 , E. Duchovni25 , l.P. Duerdoth 15 , D .. J.P. Dumas6 , P.A. Elcombe , P.G. Estabrooks6 , E. Etzion , F. Fabbr?, P. Farthouat20 , H.l\1. Fischer , D.G. Fong , 1\LT. French19 , C. Fukunaga , A. Gaidot20 , 0. GaneF5 , J.W. Garyll, .) . Gascon , N .I. Geddes19 , C.N .P. Gee19 , C. Geich-GimbeP, S. W. Gensler9 , F .X. Gentit20 , G. Giacomcll?, V. Gibson 5 , W.R. Gibson 12 , J.D. Gillies , J. Goldberg21 , i\I.J. Goodrick5 , W. Gorn4 , D. Granite21 , E. Gross25 , J. Grunhaus , H. Hagedorn 10 , J. llagemanns, 1\l.llansrouls, C.K.IIargrove7, I. Harrus21 , J. Hart5 , P.l\1. Hattersley', 1\l.llauschilds, C.l\1. Haw kess, E. Heflin 4 , R.J. llemingway6 , ltD. Heuers, J .C. llill5 , S.J. Hillier1 , D.A.llinshaw 17 , C. Ho4, J.D. Hobbs9 , P.R. Hobson', D. Hochman25 , B. HoUS, R.J. l!omer1 , S.R. Ilou16 , C.P.llowarth1\ R.E.llughcs-Jones , R. Humbert10 , P.lgo-Kemcnesn, H. lhssenll, D.C. lmrie24 , L. Janissen6 , A. Jawahery , P.\V. Jcffreys19 , H. Jeremie , M.Jimacks,.M.Jobes1 , R.W.L.Jones12 , P.Jovanovic1 , D. Karlen6 , K.Kawagoe23 , T. Kawamoto23 , R.G. Kcllogg16 , B.W. Kennedy 14 , C. Klein worts, D.E. Klem1s, G. Knop3 , T. Kobayash? , T.P. Kokott3 , L. Kopkes, R. Kowalewski6 , H. Kreutzmann\ J. Kroll , 1\I. Kuwano , P. Kyberd 12 , G.D. Lalferty'5 , F. Lamarche17 , W.J. Larson', J.G. Layter , P. Le Du20 , P. Leblanc17 , A.M. Lee16 , I\!. H. Lehto14 , D. Lellouchs, P. Lennertn, C. Leroy17 , L. Lessard17 , S. Levegriin3 , L. Levinson25 , S.L. Lloyd , F.K. Loebinger15 , J.l\1. Lorah16 , B. Lora.zo17 , 1\l.J. Losty 7, J. Ludwig10 , J. l\Ia4•b, A.A.l\!acbeth15 , 1\L 1\Iannellis, S. Marcellini2, G.l\Iaringer , A.J.l\Iartin12 , J.P. i\Iartin , T. Mashimo , P.l\Iiittig , U.l\Iaur , T.J. Mcl\!ahon 1 , J.R.l\IcNutt24 , F. Meijerss, D. Mensznern, F.S.l\Ierritt9 , H.l\Ies 7, A.l\Iichelinis, R.P. Middleton 19 , G.l\Iikenberg, J. l\!ildenbcrger6 , D.J. Miller 14 , C.l\Iilstcne22 , l\l.l\Iinowa23 , W.l\lohr10 , C.l\loisan17 , A. Montanari2 , T. Mori23 , 1\l.W. Moss , P.G.l\Iurphy' 5 , W.J.l\lurray , B. Ncllen , lUI. Nguyen , 1\l. Nozaki , A.J.P. O'Dowd15 , S.W. O'Neales,c, B.P. O'Neill', F.G. Oakham', F. Odorici2 , 1\I. Ogg6 , II. Oh 4 , 1\I.J. Oreglia9 , S. Orito23 , J.P. Pansart , G.N. Patrick19 , S.J. Pawley' 5 , P. Pfister10 , J.E. Pilcher9 , J.L. Pinfold25 , D.E. Planes, B. Pol?, A. Pouladdej", E. Prebyss, T.W. Pritchard 12 , II. Przysiezniak17 , G. Quasts, M.W. Redmond 9 , D.L. Rees1 , 1\1. Regimbald11 , K. Riles', C.M. Roach , S.A. Robins 12 , A. Rollnik3 , J.l\1. Roney9 , S. Rossberg 10 , A.M. Rossi2·•, P. Routenburg , K. Runge 10 , 0. Runolfssons, S. Sanghera6 , R.A. Sansum , 1\1. Sasaki23 , B.J. Saunders , A.D. Schaile10 , 0. Scha.ile10 , W. Schappert6 , P. Scha.rlf-Ha.nsens, S. Schreiber3 , J. Schwarz , A. Shapira.25 , B.C. Shen\ P. Sherwood", A. Simon3 , P. Singh 12 , G.P. Siroli2 , A. Skuja16 , A.M. Smiths, T.J. Smiths, G.A. Snow 16 , R.W. Springer , 1\I. Sproston , K. Stephens , H.E. Stier10 , R. Stroehmerll, D. Strom9 , H. Ta.kcda , T. Takeshita. , P. Taras, N.J. Tha.ckra.y', T. Tsukamoto23 , I\!. F. Turner5 , G. Tysarczyk-Niemeyeru, D. Va.n den pla.s , R. Va.n Kootens, G.J. VanDalen', G. Va.sseur20 ,

We present evidence for the existence of the strange b-flavoured meson B~ in a data sample of 470 628 hadronic Z decays recorded with the OPAL detector at LEP. A signal of 18.3±5.2(stat.)±0.9(syst.) D;;-£+ pairs (or charge conju,gate, R=e or R=Jl) is found after background subtraction, where the D, meson is detected in the )'lr and K*°K final states. Interpreting this signal as coming from the semileptonic deeay B~ --+ D; e+ v X and combining the two decay modes of the D., we find J(b--+ B~) · B(B~--+ D;;-R+vX) · B(D;;---+ >7r-)= (3.9±l.l(stat.)±0.8(syst.))x10-\ where J(b--+ B~) is the fraction of b quarks that result in a B~ meson in Z decays. This signal for the B~ is supported by our observation of an excess of 147±48 inclusive D, mesons in the >1r and K*°K modes above the number expected from B0 and B+ decays and from the fragmentation of primary c quarks. In addition, a search is made for the exclusive decay B~--+ JflP>. Based on one candidate event the 90% confidence level upper limit is determined to be f(b-+ B~) · B(B~ -+Jj./J>) < 0.22%. (Submitted to Physics Letters B) The 0 PAL Collaboration P.D. Acton, G. Alexander, J. Allison's, P.P. Allports, K.J. Anderson9 , S. Arcell?, A. Astbury2s, D. Axen29 , G. Azuelos1s,a, G.A. Bahan's, J.T.M. Baines's, A.H. Ball17, J. Banks's, R.J. Barlow's, S. Barnett's, J.R. Batley\ G. Bea.udoin18, A. Beck23, J. Becker10, T. Behnke27, K.W. BelP0, G. Bella, P. Berlich, S. Bethke , 0. Biebel', U. Binder10, l.J.Bloodworth , P.Bock11 , B.Boden3 , H.M.Bosch11 , S.Bougerolle29, H.Breukers, R.M. Brown20, A. Buijss, H.J. Burckharts, C. Burgard, I'. Capilupp?, R.K. Carnegies, A.A. Carter, J.R. CarterS, C.Y. Chang , D.G. Charlton8 , P.E.L. Clarke2S, I. Cohen23 , J.C. Clayton', W.J. Collins , J.E. Conboy , M. Cooper , M. Coupland , M. Cuffiani , S. Dado , G.M. Dallavalle, S. De Jong , L.A. del Pozos, H. Deng17, A. Dieckmann11 , M. Dittmar\ M.S. Dixit7 , E. do Couto e Silva12 , J.E. Duboscq , E. Duchovnis, G. Duckeck11 , l.P. Duerdoth1s, D.J.P. Dumass, P.A. ElcombeS, P.G. Estabrooks6 , E. Etzion23 , H. G. Evans9 , F. Fabbri2, M. Fincke-Keeler28, H.M. Fischer3, D.G. Fong17 , M. Foucher17, A. Gaidot 21 , 0. GaneFs, J.W. Gary\ J. Gascon , R.F. McGowan's, N.I. Geddes20, C. Geich-Gimbel3, S.W. Gensler , F.X. Gentit 21 , G. Giacomelli 2, V. Gibsons, W.R. Gibson13, J.D. Gillies20, J.Goldberg22 , M.J.Goodrick5 , W.Gorn\ C.Grandi , F.C.Grant5 , J.Hagemann27, G.G. Hanson , M. Hansroul8 , C.K. Hargrove7, P.F. Harrison1\ J. Hart8 , P.M. Hattersley', M. Hauschild , C.M. Haw kess, E. Heflin\ R.J. Hemingways, R.D. Heuer , J.C. Hill, S.J. Hillier', T. Hilse, D.A. Hinshaw, J.D. Hobbs , P.R. Hobson2s, D. Hochman26, R.J. Homer', A.K. Honma28·•, C.P. Howarth15 , R.E. Hughes-Jones16 , R. Humbert10, P. lgo-Kemenes11 , H. Ihssen11 , D.C. Imrie, A. C. Janissens, A. Jawahery, P.W. Jeffreys20 , H. Jeremie, M. Jimack2 , M. Jobes', R.W.L. Jones13, P. Jovanovic', C. Jui4 , D. Karlen6 , K. Kawagoe24, T. Kawamoto4, R.K. Keeler, R.G. Kellogg, B.W. Kennedy, S. Kluth', T. Kobayashi; T.P. Kokott3 , S. Komamiya24, L. Kopke8 , J.F. Krals, R. Kowalewski6, J. von Krogh11 , J. Kroll , M. Kuwano4, P. Kyberd, G.D. Lafferty's, F. Lamarche, J.G. Layter\ P. Le Du2', P. Leblanc1s, A.M. Lee17, M.H. Lehto15, D. Lellouch2s, P. Lennert11 , C. Leroy18, J. Letts\ S. Levegriin3 , L. Levinsons, S.L. Lloyd'', F.K. Loebinger16, J.M. Lorah17 , B. Lorazo , M.J. Losty7, X. C. Lou12 , J. Ludwig10 , M. Mannellis, S. Marcellini 2, G. Maringer3 , C. Markus3 , A.J. Martin, J.P. Martin, T. Mashimo<, P. Mattig , U. Maur', J. McKenna2s, T.J. McMahon', J.R. McNutt2s, F. Meijerss, D. Menszner11 , F.S. Merritt9 , H. Mes , A. Michelinis, R.P. Middleton, G. Mikenberg, J. Mildenberger, D.J. Miller, R. Mir, W. Mohr, C. Moisan18 , A. Montanari2 , T. Mori24, M. Mo:rii24, T. Mouthuy12 •b, B. Nellen3, H.H. Nguyen9 , M. Nozaki24, S.W. O'Neale•', F.G. Oakham, F. Odorici, H.O. Ogren12 , C.J. Oram•", M.J. Oreglia9 , S. Orito24, J.P. Pansart2', B. Panzer-Steindel8 , P. Paschievici2s, G.N. Patrick, N. Paz-Jaoshvili" , P. Pfister10 , J.E. Pilcher9 , D. Pitman28, D.E. Plane8 , P. Poffenberger28 , B. Poli2 , A. Pouladdejs, E. Prebys8 , T.W. Pritchard13, H. Przysiezniak1s, G. Quast, M.W. Redmond , D.L. Rees', G.E. RichardE

We present measurements of triple gauge boson coupling parameters using data recorded by the OPAL detector at LEP2 at a centre-of-mass energy of 172 GeV. A total of 120 W-pair candidates has been selected in the qqqq, qq`ν` and `ν`` ′ ν`′ decay channels, for an integrated luminosity of 10.4 pb. We use these data to determine several different anomalous coupling parameters using the measured cross-section and the distributions of kinematic variables. We measure αBφ=0.35 +1.29 −1.07 ± 0.38, αWφ=0.00 +0.30 −0.28 ± 0.11, αW=0.18 +0.49 −0.47 ± 0.23, ∆g z 1=−0.03 +0.40 −0.37 ± 0.14, ∆κ γ =0.03 +0.55 −0.51± 0.20, and ∆κ=0.03 +0.49 −0.46± 0.21. Combining the αWφ result with our previous result obtained from the 161 GeV data sample we measure αWφ=−0.08 +0.28 −0.25 ± 0.10. All of these measurements are consistent with the Standard Model. (To be submitted to Zeitschrift fur Physik C.) The OPAL Collaboration K. Ackerstaff, G. Alexander, J. Allison, N. Altekamp, K.J. Anderson, S. Anderson, S. Arcelli, S. Asai, D. Axen, G. Azuelos, A.H. Ball, E. Barberio, R.J. Barlow, R. Bartoldus, J.R. Batley, S. Baumann, J. Bechtluft, C. Beeston, T. Behnke, A.N. Bell, K.W. Bell, G. Bella, S. Bentvelsen, S. Bethke, O. Biebel, A. Biguzzi, S.D. Bird, V. Blobel, I.J. Bloodworth, J.E. Bloomer, M. Bobinski, P. Bock, D. Bonacorsi, M. Boutemeur, B.T. Bouwens, S. Braibant, L. Brigliadori, R.M. Brown, H.J. Burckhart, C. Burgard, R. Burgin, P. Capiluppi, R.K. Carnegie, A.A. Carter, J.R. Carter, C.Y. Chang, D.G. Charlton, D. Chrisman, P.E.L. Clarke, I. Cohen, J.E. Conboy, O.C. Cooke, M. Cuffiani, S. Dado, C. Dallapiccola, G.M. Dallavalle, R. Davis, S. De Jong, L.A. del Pozo, K. Desch, B. Dienes, M.S. Dixit, E. do Couto e Silva, M. Doucet, E. Duchovni, G. Duckeck, I.P. Duerdoth, D. Eatough, J.E.G. Edwards, P.G. Estabrooks, H.G. Evans, M. Evans, F. Fabbri, M. Fanti, A.A. Faust, F. Fiedler, M. Fierro, H.M. Fischer, I. Fleck, R. Folman, D.G. Fong, M. Foucher, A. Furtjes, D.I. Futyan, P. Gagnon, J.W. Gary, J. Gascon, S.M. Gascon-Shotkin, N.I. Geddes, C. Geich-Gimbel, T. Geralis, G. Giacomelli, P. Giacomelli, R. Giacomelli, V. Gibson, W.R. Gibson, D.M. Gingrich, D. Glenzinski, J. Goldberg, M.J. Goodrick, W. Gorn, C. Grandi, E. Gross, J. Grunhaus, M. Gruwe, C. Hajdu, G.G. Hanson, M. Hansroul, M. Hapke, C.K. Hargrove, P.A. Hart, C. Hartmann, M. Hauschild, C.M. Hawkes, R. Hawkings, R.J. Hemingway, M. Herndon, G. Herten, R.D. Heuer, M.D. Hildreth, J.C. Hill, S.J. Hillier, P.R. Hobson, R.J. Homer, A.K. Honma, D. Horvath, K.R. Hossain, R. Howard, P. Huntemeyer, D.E. Hutchcroft, P. Igo-Kemenes, D.C. Imrie, M.R. Ingram, K. Ishii, A. Jawahery, P.W. Jeffreys, H. Jeremie, M. Jimack, A. Joly, C.R. Jones, G. Jones, M. Jones, U. Jost, P. Jovanovic, T.R. Junk, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, P.I. Kayal, R.K. Keeler, R.G. Kellogg, B.W. Kennedy, J. Kirk, A. Klier, S. Kluth, T. Kobayashi, M. Kobel, D.S. Koetke, T.P. Kokott, M. Kolrep, S. Komamiya, T. Kress, P. Krieger, J. von Krogh, P. Kyberd, G.D. Lafferty, R. Lahmann, W.P. Lai, D. Lanske, J. Lauber, S.R. Lautenschlager, J.G. Layter, D. Lazic, A.M. Lee, E. Lefebvre, D. Lellouch, J. Letts, L. Levinson, S.L. Lloyd, F.K. Loebinger, G.D. Long, M.J. Losty, J. Ludwig, A. Macchiolo, A. Macpherson, M. Mannelli, S. Marcellini, C. Markus, A.J. Martin, J.P. Martin, G. Martinez, T. Mashimo, P. Mattig, W.J. McDonald, J. McKenna, E.A. Mckigney, T.J. McMahon, R.A. McPherson, F. Meijers, S. Menke, F.S. Merritt, H. Mes, J. Meyer, A. Michelini, G. Mikenberg, D.J. Miller, A. Mincer, R. Mir, W. Mohr, A. Montanari, T. Mori, M. Morii, U. Muller, S. Mihara, K. Nagai, I. Nakamura, H.A. Neal, B. Nellen, R. Nisius, S.W. O’Neale, F.G. Oakham, F. Odorici, H.O. Ogren, A. Oh, N.J. Oldershaw, M.J. Oreglia, S. Orito, J. Palinkas, G. Pasztor, J.R. Pater, G.N. Patrick, J. Patt, M.J. Pearce, R. Perez-Ochoa, S. Petzold, P. Pfeifenschneider , J.E. Pilcher, J. Pinfold, D.E. Plane, P. Poffenberger, B. Poli, A. Posthaus, D.L. Rees, D. Rigby, S. Robertson, S.A. Robins, N. Rodning, J.M. Roney, A. Rooke, E. Ros, A.M. Rossi, P. Routenburg, Y. Rozen, K. Runge, O. Runolfsson, U. Ruppel, D.R. Rust, R. Rylko, K. Sachs, T. Saeki, E.K.G. Sarkisyan, C. Sbarra, A.D. Schaile, O. Schaile, F. Scharf, P. Scharff-Hansen, P. Schenk, J. Schieck, P. Schleper, B. Schmitt, S. Schmitt, A. Schoning, M. Schroder, H.C. Schultz-Coulon, M. Schumacher, C. Schwick, W.G. Scott, T.G. Shears, B.C. Shen, C.H. Shepherd-Themistocleous , 1 P. Sherwood, G.P. Siroli, A. Sittler, A. Skillman, A. Skuja, A.M. Smith, G.A. Snow, R. Sobie, S. Soldner-Rembold, R.W. Springer, M. Sproston, K. Stephens, J. Steuerer, B. Stockhausen, K. Stoll, D. Strom, P. Szymanski, R. Tafirout, S.D. Talbot, S. Tanaka, P. Taras, S. Tarem, R. Teuscher, M. Thiergen, M.A. Thomson, E. von Torne, S. Towers, I. Trigger, Z. Trocsanyi, E. Tsur, A.S. Turcot, M.F. Turner-Watson, P. Utzat, R. Van Kooten, M. Verzocchi, P. Vikas, E.H. Vokurka, H. Voss, F. Wackerle, A. Wagner, C.P. Ward, D.R. Ward, P.M. Watkins, A.T. Watson, N.K. Watson, P.S. Wells, N. Wermes, J.S. White, B. Wilkens, G.W. Wilson, J.A. Wilson, G. Wolf, T.R. Wyatt, S. Yamashita, G. Yekutieli, V. Zacek, D. Zer-Zion School of Physics and Space Research, University of Birmingham, Birmingham B15 2TT, UK Dipartimento di Fisica dell’ Universita di Bologna and INFN, I-40126 Bologna, Italy Physikalisches Institut, Universitat Bonn, D-53115 Bonn, Germany Department of Physics, University of California, Riverside CA 92521, USA Cavendish Laboratory, Cambridge CB3 0HE, UK 6 Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada Centre for Research in Particle Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada CERN, European Organisation for Particle Physics, CH-1211 Geneva 23, Switzerland Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago IL 60637, USA Fakultat fur Physik, Albert Ludwigs Universitat, D-79104 Freiburg, Germany Physikalisches Institut, Universitat Heidelberg, D-69120 Heidelberg, Germany Indiana University, Department of Physics, Swain Hall West 117, Bloomington IN 47405, USA Queen Mary and Westfield College, University of London, London E1 4NS, UK Technische Hochschule Aachen, III Physikalisches Institut, Sommerfeldstrasse 26-28, D-52056 Aachen, Germany University College London, London WC1E 6BT, UK Department of Physics, Schuster Laboratory, The University, Manchester M13 9PL, UK Department of Physics, University of Maryland, College Park, MD 20742, USA Laboratoire de Physique Nucleaire, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada University of Oregon, Department of Physics, Eugene OR 97403, USA Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel Department of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo 113, and Kobe University, Kobe 657, Japan Brunel University, Uxbridge, Middlesex UB8 3PH, UK Particle Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel Universitat Hamburg/DESY, II Institut fur Experimental Physik, Notkestrasse 85, D-22607 Hamburg, Germany University of Victoria, Department of Physics, P O Box 3055, Victoria BC V8W 3P6, Canada University of British Columbia, Department of Physics, Vancouver BC V6T 1Z1, Canada 2 University of Alberta, Department of Physics, Edmonton AB T6G 2J1, Canada Duke University, Dept of Physics, Durham, NC 27708-0305, USA Research Institute for Particle and Nuclear Physics, H-1525 Budapest, P O Box 49, Hungary Institute of Nuclear Research, H-4001 Debrecen, P O Box 51, Hungary Ludwigs-Maximilians-Universitat Munchen, Sektion Physik, Am Coulombwall 1, D-85748 Garching, Germany a and at TRIUMF, Vancouver, Canada V6T 2A3 b and Royal Society University Research Fellow c and Institute of Nuclear Research, Debrecen, Hungary d and Department of Experimental Physics, Lajos Kossuth University, Debrecen, Hungary e and Department of Physics, New York University, NY 1003, USA

We show that the observed fluxes, spectra and sky distributions of the diffuse backgrounds of high energy astronomical neutrinos, gamma rays and cosmic ray positrons observed near Earth satisfy the simple relations expected from their common production in hadronic collisions of high energy cosmic ray nuclei with diffuse matter in/near source.

We report a study of forward-backward multiplicity correlations and a measurement of the dependence on charged multiplicity of the mean transverse momentum of charged hadrons, measured with respect to the thrust axis. The study was performed on a high statistics sample of Z 0 decays to multihadronic (cid:12)nal states collected by the OPAL Collaboration at LEP. The positive forward-backward multiplicity correlation observed in our inclusive sample can be understood in terms of a superposition of distinct event topologies characterized by a di(cid:11)erent amount of hard gluon radiation (2-, 3-and 4-jet events) and with di(cid:11)erent mean multiplicities. The residual positive correlation that we see in a clean 2-jet sample can be interpreted in terms of fragmentation properties of di(cid:11)erent quark (cid:13)avours and of the production and decay of resonances. We have compared the observed e(cid:11)ects with the predictions of QCD-based parton shower models. The data are well described by the Jetset 7.3 Monte Carlo, while Herwig 5.5 does not satisfactorily reproduce the measured correlations. Hard gluon radiation is also shown to be responsible for the observed increase of about 40% in the mean transverse momentum of produced charged hadrons in the multiplicity range from 10 to 30. The comparison with the results obtained in an analysis of a sample enriched in Z 0 ! bb events, shows that the presence of heavy (cid:13)avours does not contribute signi(cid:12)cantly to the observed e(cid:11)ect.

M easurem entsofthe lepton polarization and forward-backward polarization asym m etry near the Z resonance using the O PAL detector are described. The m easurem ents are based on analyses of ! e e , ! , ! , ! and ! a1 decays from a sam ple of 144;810 e e ! + candidates corresponding to an integrated lum inosity of 151 pb . Assum ing thatthe lepton decays according to V A theory,we m easure the average polarization near p s = M Z to be hP i = ( 14:10 0:73 0:55)% and the polarization forward-backward asym m etry to be A FB pol = ( 10:55 0:76 0:25)% ,where the rst error isstatisticaland the second system atic. Taking into account the sm alle ects ofthe photon propagator,photon-Z interference and photonic radiative corrections,these results can be expressed in term softhelepton neutralcurrentasym m etry param eters:

AbstractA search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at $\sqrt{s}=189\mbox{--}209\ \mbox{GeV}$, corresponding to an integrated luminosity of approximately 600 pb−1. Charged Higgs bosons are assumed to be pair-produced and to decay into $\mathrm{q} \bar{\mathrm{q}}$, τντ or AW±. No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are derived by combining these results with previous searches at lower energies. Under the assumption $\mathrm{BR} (\mathrm{H}^{\pm} \to \tau\nu_{\tau}) + \mathrm{BR} (\mathrm{H}^{\pm} \to \mathrm{q} \bar{\mathrm{q}}) = 1$, motivated by general 2HDM type II models, excluded areas on the $[m_{\mathrm{H}^{\pm}} , \mathrm{BR} (\mathrm {H}^{\pm} \to \tau\nu_{\tau})]$ plane are presented and charged Higgs bosons are excluded up to a mass of 76.3 GeV at 95 % confidence level, independent of the branching ratio BR(H±→τντ). A scan of the 2HDM type I model parameter space is performed and limits on the Higgs-boson masses $m_{\mathrm{H}^{\pm}}$ and mA are presented for different choices of tanβ.

The energy spectrum, composition and arrival directions of ultrahigh energy cosmic rays (UHECRs) with energy above the cosmic ray ankle, measured by the Pierre Auger Observatory, are inconsistent if their origin is assumed to be extragalactic. Their observed properties, however, are those expected from UHECRs accelerated by the highly relativistic jets emitted in Galactic gamma ray bursts, most of which are beamed away from Earth. If this alternative interpretation is correct, the observed break in the energy spectrum of UHECRs around 50 EeV is not the Greisen-Zatsepin-Kuzmin cutoff but the energy threshold for free escape of ultrahigh energy iron cosmic rays from the Galaxy and above their respective free-escape threshold-energies, UHECR nuclei should point back to their Galactic sources or their remnants rather than to active galactic nuclei (AGN) within the GZK horizon.