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A measurement of σtot(e+e- → hadrons) for cm energies between 12.0 and 36.7 GeV

Physics Letters B 113:6 (1982) 499-508

Authors:

R Brandelik, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, HG Sander, D Schmitz, D Trines, W Wallraff, H Boerner, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, B Löhr, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, S Cooper, J Franzke, D Heyland, H Hultschig, P Joos, W Koch, U Kötz, H Kowalski, A Ladage, D Lüke, HL Lynch, P Mättig, KH Mess, D Notz, J Pyrlik, DR Quarrie, R Riethmüller, W Schütte, P Söding, G Wolf, R Fohrmann, HL Krasemann, P Leu, D Pandoulas, G Poelz, O Römer, P Schmüser, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, DA Garbutt, TD Jones, WG Jones, SL Lloyd, JK Sedgbeer, RA Stern, S Yarker, KW Bell, MG Bowler, IC Brock, RJ Cashmore, R Carnegie, R Devenish, P Grossmann, J Illingworth, M Ogg, GL Salmon, J Thomas, TR Wyatt, C Youngman, B Foster, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, M Holder, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, D Revel, E Ronat, A Shapira, T Barklow, J Freeman, T Meyer, G Rudolph, E Wicklund, SL Wu, G Zobernig

Abstract:

The ration R = σ(e+e- → hadrons)σμμ was measured between 12.0 and 36.7 GeV c.m. energy W with a precision of typically ± 5.2%. R is found to be constant with an average R = 4.01 ± 0.03 (stat) ± (syst.) for W ≥ 14 GeV. Quarks are found to be point-like, the mass parameter describing a possible quark form-factor being larger than 186 GeV. Fits including QCD corrections and a weak neutral-current contribution are presented. © 1982.

Charged pion production in e+e- annihilation at 14, 22 and 34 GeV CM energy

Physics Letters B 113:1 (1982) 98-104

Authors:

R Brandelik, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, HG Sander, D Schmitz, D Trines, W Wallraff, H Boerner, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, B Löhr, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, S Cooper, D Heyland, H Hultschig, P Joos, W Koch, P Koehler, U Kötz, H Kowalski, A Ladage, D Lüke, HL Lynch, P Mättig, KH Mess, D Notz, J Pyrlik, DR Quarrie, R Reithmüller, A Shapira, P Söding, G Wolf, R Fohrmann, M Holder, HL Krasemann, P Leu, D Pandoulas, G Poelz, O Römer, R Rüsch, P Schmüser, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, DA Garbutt, TD Jones, WG Jones, SL Lloyd, JK Sedgbeer, RA Stern, S Yarker, KW Bell, MG Bowler, IC Brock, RJ Cashmore, R Carnegie, R Devenish, P Grossmann, J Illingworth, M Ogg, GL Salmon, J Thomas, TR Wyatt, C Youngman, B Foster, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, D Revel, E Ronat, T Barklow, J Freeman, P Lecomte, T Meyer, G Rudolph, E Wicklund, S Lan Wu, G Zobernig

Abstract:

The inclusive production of π± mesons in e+e- annihilation has been measured at c.m. energies of 14, 22 and 34 GeV for pion momenta between 0.3 ans 10 GeV/c. The fraction of pions among the charged hadrons is above 90% at 0.4 GeV/c and decreases to about 50% at high momenta. The scaled cross sections ( s β) dσ dx at 14, 22 and 34 GeV as well as the 5.2 GeV data from DASP have a rather similar x dependence. After integration over the x range from 0.2 to 0.6 the cross sections indicate a monotonic decrease with increasing centre-of-mass energy. © 1982.

Charge asymmetry and weak interaction effects in e+e-→μ+μ- and e+e-→τ+τ-

Physics Letters B 110:2 (1982) 173-180

Authors:

R Brandelik, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, HG Sander, D Schmitz, D Trines, W Wallraff, H Boerner, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, B Löhr, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, S Cooper, D Heyland, H Hultschig, P Joos, W Koch, U Kötz, H Kowalski, A Ladage, D Lüke, HL Lynch, P Mättig, KH Mess, D Notz, J Pyrlik, DR Quarrie, R Riethmüller, A Shapira, P Söding, G Wolf, R Fohrmann, M Holder, HL Krasemann, P Leu, D Pandoulas, G Poelz, O Römer, P Schmüser, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, DA Garbutt, TD Jones, WG Jones, SL Lloyd, JK Sedgbeer, RA Stern, S Yarker, KW Bell, MG Bowler, IC Brock, RJ Cashmore, R Carnegie, R Devenish, P Grossmann, J Illingworth, M Ogg, GL Salmon, J Thomas, TR Wyatt, C Youngman, B Foster, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, D Revel, E Ronat, T Barklow, J Freeman, T Meyer, G Rudolph, E Wicklund, SL Wu, G Zobernig

Abstract:

We have measured, at an average centre-of-mass energy of 34.22 GeV a forward-backward charge asymmetry in the reaction e+e-→μ+μ- of value -0.161 ± 0.032. This demonstrates the existence of an axial vector neutral current with coupling strength of geagμa=0.53 ± 0.10. We have also obtained a limit on the vector coupling strength of gevgμv<0.12. The Weinberg angle is found to be sin2θW=0.29+0.09-0.11. From the reaction e+e-→τ+τ- we have found geagτa<0.34, gevgτv<0.55. © 1982.

Angular correlations in γγ→ÒÏ0ÒÏ0 near threshold

Zeitschrift Fur Physik C Particles and Fields 16:1 (1982) 13-25

Authors:

M Althoff, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, HG Sander, D Schmitz, H Siebke, D Trines, W Wallraff, H Boerner, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, S Cooper, J Franzke, H Hultschig, P Joos, W Koch, U Kötz, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, KH Mess, D Notz, J Pyrlik, DR Quarrie, R Riethmüller, W Schütte, P Söding, G Wolf, G Yekutieli, M Dittmar, R Fohrmann, HL Krasemann, P Leu, E Lohrmann, D Pandoulas, G Poelz, O Römer, P Schmüser, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, DA Garbutt, TD Jones, WG Jones, SL Lloyd, J McCardle, JK Sedgebeer, KW Bell, MG Bowler, IC Brock, RJ Cashmore, R Carnegie, PEL Clarke, R Devenish, P Grossmann, J Illingworth, GL Salmon, J Thomas, TR Wyatt, C Youngman, B Foster, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, D Heyland, M Holder, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, D Revel, E Ronat, A Shapira, T Barklow, T Meyer, G Rudolph, H Venkataramania, E Wicklund, SL Wu

Abstract:

We present an analysis of ÒÏ0ÒÏ0 production by two photons in the ÒÏ0ÒÏ0 invariant mass range from 1.2 to 2.0 GeV. From a study of the angular correlations in the process γγ→ÒÏ0ÒÏ0→϶Ä- Ï€+Ï€- we exclude a dominant contribution from JP=0- or 2- states. The data indicate sizeable contributions from JP=0+ for four pion masses M4Ï€<1.7 GeV and from JP=2+ for M4Ï€>1.7 GeV. The data are also well described by a model with isotropic production and uncorrelated isotropic decay of the ÒÏ0,s. The cross section stays high below the nominal ÒÏ0ÒÏ0 threshold, i.e. M4Ï€<1.5 GeV. The matrix element for ÒÏ0ÒÏ0 production is found to decrease steeply with increasing M4Ï€. Upper limits for the couplings of the ι(1440) and Θ(1640) to γγ and ÒÏ0ÒÏ0 are given:Γ(ι→γγ)·B(ι→ÒÏ 0ÒÏ0)<1.0 keV and Γ(Θ→γγ) © 1982 Springer-Verlag.

Exclusive proton-antiproton production in two-photon collisions

Physics Letters B 108:1 (1982) 67-70

Authors:

R Brandelik, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, HG Sander, D Schmitz, AS von Dratzig, D Trines, W Wallraff, H Boerner, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, P Leu, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, S Cooper, D Heyland, H Hultschig, P Joos, W Koch, U Kötz, H Kowalski, A Ladage, D Lüke, HL Lynch, P Mättig, KH Mess, D Notz, J Pyrlik, DR Quarrie, R Riethmüller, A Shapira, P Söding, BH Wiik, G Wolf, R Fohrmann, M Holder, HL Krasemann, G Poelz, O Römer, P Schmüser, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, DA Garbutt, TD Jones, WG Jones, SL Lloyd, D Pandoulas, JK Sedgebeer, RA Stern, S Yarker, MG Bowler, IC Brock, RJ Cashmore, R Devenish, P Grossmann, J Illingworth, M Ogg, GL Salmon, J Thomas, TR Wyatt, C Youngman, KW Bell, B Foster, JC Hart, J Proudfoot, DH Saxon, PL Woodworth, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, D Revel, E Ronat, T Barklow, J Freeman, T Meyer, G Rudolph, E Wicklund, SL Wu, G Zobernig

Abstract:

Production of proton-antiproton pairs by two-photon scattering has been observed at the electron-position storage ring PETRA. A total of eight proton-antiproton pairs have been identified using the time-of-flight technique. We have measured a total cross section of 4.5 ± 0.8 nb in the photon-photon c.m. energy range 2.0-2.6 GeV. © 1982.