Production of L Lambda and S0 Sigma {0}_{} hyperons in proton-proton collisions

Abdel-Bary, M.; Wuestner, P.; Lehmann, A.; Gillitzer, A.; Meyer, W.; Wenzel, R.; Clement, H.; Teufel, A.; Stinzing, F.; Naumann, L.; Wirth, S.; Georgi, J.; Jaekel, R.; Kuhlmann, E.; Schoenmeier, P; Moeller, K.; Jaeger, H.; Dietrich, J.; Pinna, L.; Freiesleben, H.; Ritman, J.; Hesselbarth, D.; AbdEl-Samad, S.; Roderburg, E.; Ullrich, W.; Kress, J.; Zupranski, P.; Marcello, S.; Reimann, S.; Michel, P.; Sefzick, T.; Schulte-Wissermann, M.; Gast, W.; Filges, D.; Filippi, A.; Mauro, S.; Eyrich, W.; Sun, G.; Karsch, L.; Wagner, M.; Jakob, B.; Wagner, G. J.; Brinkmann, K.; Marwinski, S.; Kilian, K.; Koch, H.; Erhardt, A.; Moertel, H.; Schamlott, A.; Krapp, M.; Paul, N.; Steinke, M.; Gottwald, J.; Fritsch, M.; Wilms, A.; Pizzolotto, C.; Waechter, J.; Dorochkevitch, E.; Schroeder, W.; Morsch, H.P.; Wintz, P.; Dshemuchadse, S.; Plettner, C.; Richter, M.; Ehrhardt, K.

doi:10.1140/epja/i2010-11023-0

Journal Article

Production of L Lambda and S0 Sigma {0}_{} hyperons in proton-proton collisions

Abdel-Bary, M.FZJ* ; AbdEl-Samad, S.FZJ* ; Brinkmann, K. ; Clement, H. ; Dietrich, J. ; Dorochkevitch, E. ; Dshemuchadse, S. ; Ehrhardt, K. ; Erhardt, A. ; Eyrich, W. ; Filges, D.FZJ* ; Filippi, A. ; Freiesleben, H. ; Fritsch, M. ; Gast, W.FZJ* ; Georgi, J. ; Gillitzer, A. ; Gottwald, J. ; Hesselbarth, D. ; Jaeger, H. ; Jakob, B. ; Jaekel, R.FZJ* ; Karsch, L. ; Kilian, K.FZJ* ; Koch, H. ; Krapp, M. ; Kress, J. ; Kuhlmann, E. ; Lehmann, A. ; Marcello, S. ; Marwinski, S.FZJ* ; Mauro, S. ; Meyer, W. ; Michel, P. ; Moeller, K. ; Moertel, H. ; Morsch, H. P. ; Naumann, L. ; Paul, N.FZJ* ; Pinna, L. ; Pizzolotto, C. ; Plettner, C. ; Reimann, S. ; Richter, M. ; Ritman, J.FZJ* ; Roderburg, E.FZJ* ; Schamlott, A. ; Schoenmeier, P. ; Schulte-Wissermann, M. ; Schroeder, W. ; Sefzick, T.FZJ* ; Steinke, M. ; Stinzing, F. ; Sun, G. ; Teufel, A. ; Ullrich, W. ; Waechter, J. ; Wagner, G. J. ; Wagner, M. ; Wenzel, R. ; Wilms, A. ; Wintz, P.FZJ* ; Wirth, S. ; Wuestner, P.FZJ* ; Zupranski, P.

2010
Springer Berlin

The European physical journal / A 46, 27 - 44 (2010) [10.1140/epja/i2010-11023-0]

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Please use a persistent id in citations: http://hdl.handle.net/2128/10303 doi:10.1140/epja/i2010-11023-0

Abstract: This paper reports results on simultaneous measurements of the reaction channels pp -> pK(+) Lambda and pp -> pK(+)Sigma(0) at excess energies of 204, 239, and 284 MeV (Lambda) and 127, 162, and 207 MeV (Sigma(0)). Total and differential cross-sections are given for both reactions. It is concluded from the measured total cross-sections that the high-energy limit of the cross-section ratio is almost reached at an excess energy of only about 200 MeV. From the differential distributions observed in the overall CMS as well as in the Jackson and helicity frames, a significant contribution of interfering nucleon resonances to the Lambda production mechanism is concluded while resonant Sigma(0) production seems to be of lesser importance and takes place only through specific partial waves of the entrance channel. The data also indicate that kaon exchange plays a minor role in the case of Lambda but an important role for Sigma(0) production. Thus the peculiar energy dependence of the Lambda/Sigma(0) cross-section ratio appears in a new light as its explanation requires more than mere differences between the p Lambda and the p Sigma(0) final-state interaction. The data provide a benchmark for theoretical models already available or yet to come.

Keyword(s): Lambda: hadroproduction ; Sigma0: hadroproduction ; cross section: ratio ; K: exchange ; differential cross section: angular dependence ; final-state interaction ; channel cross section: energy dependence ; nucleon resonance ; p p: exclusive reaction ; K+: associated production ; Dalitz plot ; helicity ; scattering amplitude: interference ; COSY-TOF ; experimental results ; Juelich COSY PS ; p p --> Lambda p K+ ; p p --> Sigma0 p K+ ; 2.950: 3.059: 3.200 GeV/c

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Note: The authors would like to express their gratitude to the COSY staff for the operation of the accelerator during the experiments. Discussions with V. A. Nikonov, A. V. Sarantsev and A. A. Sibirtsev are gratefully acknowledged. This work was supported in part by grants from BMBF and Forschungszentrum Julich (COSY-FFE).; 18 pages, 10 figures; accepted by The European Physical Journal A (EPJ A)

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