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Angular correlations in γγ→ρ0ρ0 near threshold

Zeitschrift für 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 ρ0ρ0 production by two photons in the ρ0ρ0 invariant mass range from 1.2 to 2.0 GeV. From a study of the angular correlations in the process γγ→ρ0ρ0→π- π+π- we exclude a dominant contribution from JP=0- or 2- states. The data indicate sizeable contributions from JP=0+ for four pion masses M4π<1.7 GeV and from JP=2+ for M4π>1.7 GeV. The data are also well described by a model with isotropic production and uncorrelated isotropic decay of the ρ0,s. The cross section stays high below the nominal ρ0ρ0 threshold, i.e. M4π<1.5 GeV. The matrix element for ρ0ρ0 production is found to decrease steeply with increasing M4π. Upper limits for the couplings of the ι(1440) and Θ(1640) to γγ and ρ0ρ0 are given:Γ(ι→γγ)·B(ι→ρ 0ρ0)<1.0 keV and Γ(Θ→γγ) © 1982 Springer-Verlag.
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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.
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π0 production by e+e- annihilation at 14 and 34 GeV c.m. energy

Physics Letters B 108:1 (1982) 71-76

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 Sedgbeer, 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:

The process e+e-→ π0 + anything has been measured at c.m. energies of 14 and 34 GeV for π0 energies between 0.5 and 4 GeV. The ratio of π0 to π± production for π momenta between 0.5 and 1.5 GeV/c is measured to be 2σ(π0)/ [σ(π+) + σ(π-)] = 1.3 ± 0.4 (1.2 ± 0.4) at 14 (34) GeV. The scaled cross section (s/μ)dσ/dx when compared with lower energy (4.9-7.4 GeV) π0 data indicates a substantial scaling violation. © 1982.
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ANGULAR-CORRELATIONS IN GAMMA-GAMMA-]RHO0-RHO0 NEAR THRESHOLD

ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS 16:1 (1982) 13-25

Authors:

M ALTHOFF, W BRAUNSCHWEIG, K GATHER, FJ KIRSCHFINK, K LUBELSMEYER, 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 KOPKE, H KOLANOSKI, R WEDEMEYER, N WERMES, M WOLLSTADT, H BURKHARDT, S COOPER, J FRANZKE, H HULTSCHIG, P JOOS, W KOCH, U KOTZ, H KOWALSKI, A LADAGE, B LOHR, D LUKE, P MATTIG, KH MESS, D NOTZ, J PYRLIK, DR QUARRIE, R RIETHMULLER, W SCHUTTE, P SODING, G WOLF, G YEKUTIELI, M DITTMAR, R FOHRMANN, HL KRASEMANN, P LEU, E LOHRMANN, D PANDOULAS, G POELZ, O ROMER, P SCHMUSER, BH WIIK, I ALAGIL, 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, G ZOBERNIG
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CHARGE ASYMMETRY AND WEAK INTERACTION EFFECTS IN EPSILON+ EPSILON- -] MU+ MU- AND EPSILON+ EPSILON- -] TAU+ TAU-

PHYSICS LETTERS B 110:2 (1982) 173-180

Authors:

R BRANDELIK, W BRAUNSCHWEIG, K GATHER, FJ KIRSCHFINK, K LUBELSMEYER, 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 KOPKE, H KOLANOSKI, B LOHR, R WEDEMEYER, N WERMES, M WOLLSTADT, H BURKHARDT, S COOPER, D HEYLAND, H HULTSCHIG, P JOOS, W KOCH, U KOTZ, H KOWALSKI, A LADAGE, D LUKE, HL LYNCH, P MATTIG, KH MESS, D NOTZ, J PYRLIK, DR QUARRIE, R RIETHMULLER, A SHAPIRA, P SODING, G WOLF, R FOHRMANN, M HOLDER, HL KRASEMANN, P LEU, D PANDOULAS, G POELZ, O ROMER, P SCHMUSER, BH WIIK, I ALAGIL, 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
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