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A measurement of muon pair production in e+e- annihilation at centre of mass energies 35.0≤ {Mathematical expression}≤46.8 GeV

Zeitschrift für Physik C Particles and Fields 40:2 (1988) 163-170

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, E Bernardi, J Chwastowski, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, D Notz, JM Pawlak, KU Pösnecker, E Ros, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, J Hassard, J Shulman, D Su, F Barreiro, L Hervas, A Leites, J del Peso, M Traseira, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, CM Hawkes, GP Heath, PN Ratoff, IM Silvester, IR Tomalin, ME Veitch, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, AN Wainer, G Yekutieli, D Muller, S Ritz, D Strom, M Takashima, SL Wu, G Zobernig

Abstract:

The reaction e+e-→μ+μ- has been studied at centre of mass energies between 35.0 and 46.8 GeV using the TASSO detector at PETRA. We present measurements of the forward-backward charge asymmetry (Aμμ) and cross section σμμ for this reaction at three energies. At 35.0 GeV we obtain a cross section relative to the QED prediction of Rμμ=σμμ/σo=0.932±0.018±0.044 and Aμμ=(-10.6-2.3+2.2±0.5)%. At 38.3 GeV we find Rμμ=0.951±0.072-0.057+0.063 and Aμμ=(+1.7-8.6+8.5±0.5)%. At 43.6 GeV we measure Rμμ=0.921±0.037±0.055 and Aμμ=(-17.6-4.3+4.4±0.5)%. Our results are in good agreement with the predictions of the standard model. Including previous TASSO data we present improved determinations of muonic electroweak parameters. We also report on lower limits of possible contributions from contact interactions. © 1988 Springer-Verlag.
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A measurement of the τ lifetime

Zeitschrift für Physik C Particles and Fields 39:3 (1988) 331-337

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, E Bernardi, J Chwastowski, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, D Notz, JM Pawlak, KU Pösnecker, E Ros, W Schütte, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, DM Binnie, J Hassard, J Shulman, D Su, F Barreiro, A Leites, J del Peso, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, GP Heath, DJ Mellor, P Ratoff, I Silvester, I Tomalin, E Veitch, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, A Shapira, N Wainer, G Yekutieli, A Caldwell, D Muller, S Ritz, D Strom, M Takashima, E Wicklund, SL Wu, G Zobernig

Abstract:

We have reconstructed 695 three-track τ decay vertices using a high resolution drift chamber close to the interaction point. From the distribution of decay lengths we measure the lifetime to be (3.06 ±0.20±0.14)×10−13 s. Using this result we find that the ratio of charged weak coupling constant for the τ to that of the μ, Gτ/Gμ=0.967±0.040 consistent with the concept of lepton universality. © 1988, Springer-Verlag. All rights reserved.
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A search for particles with magnetic charge produced in e+e- annihilations at 543-1543-1543-1GeV

Zeitschrift für Physik C Particles and Fields 38:4 (1988) 543-550

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, P Rosskamp, B Bock, J Eisenmann, HM Fischer, H Hartmann, E Hilger, A Jocksch, V Mertens, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, E Bernardi, J Chwastowski, Y Eisenberg, A Eskreys, K Gather, H Hultschig, K Genser, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, A Montag, D Notz, JM Pawlak, E Ronat, D Trines, T Tymieniecka, R Walczak, G Wolf, W Zeuner, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, KU Pösnecker, DM Binnie, J Hassard, JK Sedgbeer, J Shulman, D Su, AT Watson, F Barreiro, A Leites, J del Peso, E Ros, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, P Dauncey, GP Heath, DJ Mellor, P Ratoff, I Tomalin, JM Yelton, SL Lloyd, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, U Karshon, G Mikenberg, D Revel, A Shapira, N Wainer, G Yekutieli, G Baranko, A Caldwell, M Cherney, JM Izen, D Muller, S Ritz, S Strom, M Takashima, E Wicklund, SL Wu, G Zobernig

Abstract:

By seeking to identify magnetically charged particles by their trajectories in a magnetic field, we set limits on the production of monopoles and dyons, via the process e+e-→γ*→M {Mathematical expression}, of masses up to 17 GeV and of magnetic charges between 10 e and 70 e © 1988 Springer-Verlag.
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A study of Bhabha scattering at PETRA energies

Zeitschrift für Physik C Particles and Fields 37:2 (1988) 171-177

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, P Rosskamp, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, V Mertens, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, F Barreiro, E Bernardi, J Chwastowski, Y Eisenberg, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, A Montag, D Notz, J Pawlak, E Ronat, E Ros, D Trines, T Tymieniecka, R Walczak, G Wolf, W Zeuner, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, KU Pösnecker, DM Binnie, JK Sedgbeer, J Shulman, D Su, AT Watson, JP Cerezo, MA Garcia, A Leites, J del Peso, JF de Troconiz, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, P Dauncey, GP Heath, DJ Mellor, P Ratoff, I Tomalin, JM Yelton, SL Lloyd, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, U Karshon, G Mikenberg, D Revel, A Shapira, N Wainer, G Yekutieli, G Baranko, A Caldwell, JM Izen, D Muller, S Ritz, D Strom, M Takashima, E Wicklund, SL Wu, G Zobernig

Abstract:

We report on high statistics Bhabha scattering data taken with the TASSO experiment at PETRA at center of mass energies from 12 GeV to 46.8 GeV. We present an analysis in terms of electroweak parameters of the standard model, give limits on QED cut-off parameters and look for possible signs of compositeness. © 1988 Springer-Verlag.
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Measurement of the two-photon reaction γγ →π+π-π+π- at large values of Q2

Zeitschrift für Physik C Particles and Fields 41:3 (1988) 353-357

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, F Barreiro, E Bernardi, J Chwastowski, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, D Notz, JM Pawlak, KU Pösnecker, E Ros, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, DM Binnie, J Hassard, J Shulman, D Su, A Leites, J del Peso, C Balkwill, MG Bowler, PN Burrows, GP Heath, PN Ratoff, IM Silvester, IR Tomalin, ME Veitch, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, A Shapira, N Wainer, G Yekutieli, A Caldwell, D Muller, S Ritz, D Strom, M Takashima, E Wicklund, SL Wu, G Zobernig

Abstract:

The process γγ→π+π-π+π- has been investigated in reactions of the type e+e-→e+e-π+π-π+π- in the single tag mode. The range of the four momentum squared of one of the virtual photons was 0.28 GeV2/c2≦Q2≦3.6 GeV2/c2, the average being 〈Q2〉=0.92 GeV2/c2; the other photon was quasi real. The reaction is mainly described by the channels γγ→ρ0ρ0 and γγ→4π (phase space), occuring with about equal probability. The Q2-dependence of the cross section is in agreement with the ρ form factor. © 1988 Springer-Verlag.
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