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Evidence for direct photons from quarks in electron-positron annihilation

Zeitschrift für Physik C Particles and Fields 41:3 (1988) 385-393

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, T Tymieniecka, R Walczak, G Wolf, H Kolanoski, W Gerhardt, T Kracht, J Krüger, E Lohrmann, G Poelz, P Rehders, G Tysarczyk, W Zeuner, J Hassard, J Shulman, D Su, A Leites, J del Peso, C Balkwill, MG Bowler, PN Burrows, GP Heath, P Ratoff, I 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, D Muller, S Ritz, D Strom, M Takashima, SL Wu, G Zobernig

Abstract:

Hadronic events from e+e--annihilations with a high energy isolated photon have been investigated at C.M. energies between 14 GeV and 44 GeV. A forward-backward asymmetry Aγ of the positively charged jet with respect to the incident positron direction has been found:Aγγ=-0.32±0.07, providing evidence for photon bremsstrahlung from quarks. The forward-backward asymmetry of all hadronic events at C.M. energies between 30 GeV and 36 GeV has been measured. The value, corrected for the limited polar angle acceptance of the detector, is:A=+0.021±0.005. © 1988 Springer-Verlag.
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Jet fragmentation and QCD models in e+e- annihilation at c.m. energies between 12.0 and 41.5 GeV

Zeitschrift für Physik C Particles and Fields 41:3 (1988) 359-373

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, A Leites, J del Peso, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, 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, D Muller, S Ritz, D Strom, M Takashima, SL Wu, G Zobernig

Abstract:

The large amount of data accumulated by the TASSO detector at 35 GeV c.m. energy has been compared with the predictions of the latest generation of perturbative QCD+fragmentation models. By adjustment of the arbitrary parameters of these models, a very good description of the global properties of hadronic events was obtained. No one model gave the best description of all features of the data, each model being better than the others for some observables and worse in other quantities. We interpret these results in terms of the underlying QCD and hadronisation schemes. The trends of the data across the energy range 12.0≦W≦41.5 GeV are generally well reproduced by the models with the parameters optimised at 35 GeV. © 1988 Springer-Verlag.
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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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