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Differential cross sections for γγ→p-p in the CM energy range from 2.0 to 3.1 GeV

Physics Letters B 130:6 (1983) 449-453

Authors:

M Althoff, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, P Rosskamp, HG Sander, D Schmitz, H Siebke, W Wallraff, HM Fischer, H Hartmann, W Hillen, A Jocksch, G Knop, L Köpke, H Kolanoski, H Kück, R Wedemeyer, N Wermes, M Wollstadt, S Cooper, Y Eisenberg, 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, M Rushton, W Schütte, D Trines, G Wolf, C Xiao, R Fohrmann, E Hilger, T Kracht, HL Krasemann, P Leu, E Lohrmann, D Pandoulas, G Poelz, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, B Foster, DA Garbutt, TD Jones, WG Jones, J McCardle, JK Sedgbeer, KW Bell, MG Bowler, IC Brock, RJ Cashmore, PEL Clarke, R Devenish, P Grossmann, SL Lloyd, GL Salmon, J Thomas, TR Wyatt, C Youngman, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, F Barreiro, M Dittmar, D Heyland, M Holder, B Neumann, E Duchovni, U Karshon, G Mikenberg, R Mir, D Revel, E Ronat, A Shapira, G Yekutieli, T Barklow, A Caldwell, M Cherney, JM Izen, M Mermikides, G Rudolph

Abstract:

Exclusive production of proton-antiproton pairs by two photon scattering at CM energies between 2.0 GeV and 3.1 GeV has been measured with the TASSO detector at the e+e- storage ring PETRA. The angular distribution is flat within the accepted CM angular range |cos Θ*|≤0.7. The integrated cross section (|cos Θ*|≤0.6) drops from about 4 nb at 2 GeV to less than 0.5 nb above 3 GeV. For the two-photon production of the ηc(2984) and its subsequent decay into proton-antiproton the upper limit Γ(ηc→γγ)·B(η c→pp)<0.32 keV (95% CL) is found. © 1983.
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Observation of Ξ-, Ξ- production in e+e- anihilation

Physics Letters B 130:5 (1983) 340-344

Authors:

M Althoff, W Braunschweig, K Gather, FJ Kirschfink, K Lübelsmeyer, HU Martyn, G Peise, J Rimkus, P Rosskamp, HG Sander, D Schmitz, H Siebke, W Wallraff, HM Fischer, H Hartmann, W Hillen, A Jocksch, G Knop, L Köpke, H Kolanoski, H Kück, R Wedemeyer, N Wermes, M Wollstadt, Y Eisenberg, 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, M Rushton, W Schütte, D Trines, G Wolf, C Xiao, R Fohrmann, E Hilger, T Kracht, HL Krasemann, P Leu, E Lohrmann, D Pandoulas, G Poelz, BH Wiik, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, B Foster, DA Garbutt, C Jenkins, TD Jones, WG Jones, J McCardle, JK Sedgbeer, WAT Wan Abdullah, KW Bell, MG Bowler, IC Brock, RJ Cashmore, PEL Clarke, R Devenish, P Grossmann, SL Lloyd, GL Salmon, J Thomas, TR Wyatt, C Youngman, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, F Barreiro, M Dittmar, D Heyland, M Holder, B Neumann, E Duchovni, U Karshon, G Mikenberg, R Mir, D Revel, E Ronat, A Shapira, G Yekutieli, T Barklow, A Caldwell, M Cherney, JM Izen, M Mermikides, G Rudolph

Abstract:

We present evidence for the production of Ξ·-, Ξ- in e+e- annihilation into hadrons. Our measurements yields: 0.026 ± 0.008 (stat.) ± 0.009 (syst.) Ξ-,Ξ- per hadronic event at W ∼ 34 GeV. Using our previous measurements of Λ, Λ and p,p production we obtain the relative yields (Ξ-, Ξ-/(Λ, Λ = 0.087 ± 0.03 (stat.) ± 0.03 (syst.) and (Ξ-, Ξ-/(p, p = 0.033 ± 0.011 (stat.) ± 0.011 (syst.). © 1983.
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Search for new SS states in the K− induced K+K− system

Nuclear Physics B Elsevier 224:2 (1983) 193-217

Authors:

T Armstrong, M Baubillier, JC Brient, W Beusch, IJ Bloodworth, G Boca, M Bonesini, D Bortoletto, A Burns, JN Carney, G Cecchet, G Costa, C Evangelista, B Ghidini, JB Kinson, V Lenti, L Mandelli, F Navach, A Palano, L Perini, Y Pons, E Quercigh, Z Strachman, M Tamborini, MF Worsell, G Zito, R Zitoun
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D*± production by e+e- annihilation near 34.4 GeV cm energy

Physics Letters B 126:6 (1983) 493-498

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, HM Fischer, H Hartmann, E Hilger, W Hillen, G Knop, L Köpke, H Kolanoski, H Kück, R Wedemeyer, N Wermes, M Wollstadt, H Burkhardt, H Hultschig, P Joos, W Koch, U Kötz, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, KH Mess, D Notz, J Pyrlik, D Quarrie, R Riethmüller, AM Rushton, W Schütte, G Wolf, G Yekutieli, R Fohrmann, HL Krasemann, P Leu, E Lohrmann, D Pandoulas, G Poelz, BH Wiik, I Al-Agil, R Beuselinck, DM Binnie, AJ Campbell, PJ Dornan, B Foster, DA Garbutt, TD Jones, WG Jones, J McCardle, JK Sedgbeer, KW Bell, MG Bowler, IC Brock, RJ Cashmore, PEL Clarke, R Devenish, P Grossmann, SL Lloyd, GL Salmon, J Thomas, TR Wyatt, C Youngman, JC Hart, J Harvey, J Proudfoot, DH Saxon, PL Woodworth, D Heyland, M Holder, M Dittmar, E Duchovni, Y Eisenberg, D Hochman, U Karshon, G Mikenberg, R Mir, D Revel, E Ronat, A Shapira, T Barklow, M Cherney, JM Izen, G Rudolph, D Strom, H Venkataramania, E Wicklund, Sau Lan Wu, G Zobernig

Abstract:

D*± production via e+e-→D*±X has been measured at an average CM energy of 34.4 GeV. The D*± energy spectrum is hard, with a maximum near χ = 0.6. The size of the D* cross section, RD* = σ(e+e- → D*X) σμμ = 2.50 ± 0.64 ± 0.88 (assuming RD*0 = RD*+) indicates that a large fraction of charm quark production yields D* mesons. The D*± angular distribution exhibits a forward-backward asymmetry, A = -0.28 ± 0.13. This is consistent with that expected in the standard theory for weak neutral currents and leads to |gAc| = 0.89 ± 0.44 for the axial vector coupling of the charm quark. © 1983.
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Charged hadron composition of the final state in e+e- annihilation at high energies

Zeitschrift für Physik C Particles and Fields 17:1 (1983) 5-15

Authors:

M Althoff, R Brandelik, 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, H Kück, 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, 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, J Freeman, P Lecomte, T Meyer, G Rudolph

Abstract:

The inclusive production of π± and K± mesons and of protons and antiprotons in e+e- annihilation has been measured at c.m. energies of W=14, 22 and 34GeV. Using time of flight measurements and Cerenkov counters the full momentum range has been covered. Differential cross sections and total particle yields are given. At particle momenta of 0.4 GeV/c more than 90% of the charged hadrons are pions. With increasing momentum the fraction of pions among the charged hadrons decreases. At W=34 GeV and a momentum of 5 GeV/c the particle fractions are approximately π±:K±:p, {Mathematical expression}. On average an event at W=34 GeV contains 10.3±0.4π±, 2.0±0.2 K± and 0.8±0.1 p, {Mathematical expression}. In addition, we present results on baryon correlations using a sample of events where two or more protons and/or antiprotons are observed in the final state. © 1983 Springer-Verlag.
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