Production of $ \Lambda$ and $ \Sigma^{0}_{}$ hyperons in proton-proton collisions
Production of $ \Lambda$ and $ \Sigma^{0}_{}$ hyperons in proton-proton collisions
复制标题
质子-质子碰撞中 $ Lambda$ 和 $ Sigma^{0}_{}$ 超子的产生
DOI：
10.1140/epja/i2010-11023-0
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
The COSY
中科院分区：
文献类型：
--
作者：
M. Abdel;S. Abdel;K. Brinkmann;H. Clement;J. Dietrich;E. Doroshkevich;S. Dshemuchadse;K. Ehrhardt;A. Erhardt;W. Eyrich;D. Filges;A. Filippi;H. Freiesleben;M. Fritsch;W. Gast;J. Georgi;A. Gillitzer;J. Gottwald;D. Hesselbarth;H. Jäger;B. Jakob;R. Jäkel;L. Karsch;K. Kilian;H. Koch;M. Krapp;J. Kress;E. Kuhlmann;A. Lehmann;S. Marcello;S. Marwinski;S. Mauro;W. Meyer;P. Michel;K. Möller;H. Morsch;H. Mörtel;L. Naumann;N. Paul;L. Pinna;C. Pizzolotto;C. Plettner;S. Reimann;M. Richter;J. Ritman;E. Roderburg;A. Schamlott;P. Schönmeier;W. Schroeder;M. Schulte;T. Sefzick;F. Stinzig;M. Steinke;G. Sun;A. Teufel;W. Ullrich;G. Wagner;M. Wagner;R. Wenzel;A. Wilms;P. Wintz;S. Wirth;P. Wüstner;P. Żupránski;The COSY
Abstract.This paper reports results on simultaneous measurements of the reaction channels pp$ \rightarrow$pK+$ \Lambda$ and pp$ \rightarrow$pK+$ \Sigma^{0}_{}$ at excess energies of 204, 239, and 284MeV ($ \Lambda$ and 127, 162, and 207MeV ($ \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 200MeV. 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.
Abstract.This paper reports results on simultaneous measurements of the reaction channels pp$ \rightarrow$pK+$ \Lambda$ and pp$ \rightarrow$pK+$ \Sigma^{0}_{}$ at excess energies of 204, 239, and 284MeV ($ \Lambda$ and 127, 162, and 207MeV ($ \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 200MeV. 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.