Spin dependence of {\eta} meson production in proton-proton collisions close to threshold

6533b82ffe1ef96bd12946a6

RESEARCH PRODUCT

Spin dependence of {\eta} meson production in proton-proton collisions close to threshold

M. Bashkanov Günter Kemmerling A. Erven I. Schätti-ozerianska K. Sitterberg G. Sterzenbach W. Eyrich A. Magiera B. Lorentz H. P. Morsch O. Khreptak Ralf Engels N. Hüsken Paweł Moskal Zbigniew Rudy Marcin Zieliński Eryk Czerwiński C.-o. Gullström Markus Büscher Harald Kleines Ankhi Roy W. Bardan Aleksandra Wrońska Hans Calén E. Perez Del Rio T. Sefzick Stanisław Kistryn J. Zabierowski K. Pysz V. Hejny Akira Yamamoto Kjell Fransson Lena Heijkenskjöld D. Prasuhn Antoni Szczurek A. Khoukaz Magdalena Skurzok B. Mariański K. Grigoryev Jozef Zlomanczuk Wojciech Krzemien V. Sopov Andrzej Kupsc Patrik Adlarson Frank Goldenbaum Pawel Marciniewski Damian Pszczel B. Shwartz J. Stepaniak P. Zupranski D. Lersch J. Ritman A. Trzcinski G. Khatri P. Fedorets W. Augustyniak Tord Johansson L. Jarczyk W. Erven V. Serdyuk Steven D. Bass H. Ohm H. Clement M. Berłowski K. Föhl K. Lalwani A. Bondar H. Stroeher Maria Zurek Jerzy Smyrski B. Kamys P. Wüstner B. Kłos T. Skorodko S. Schadmand K. Demmich A. Pyszniak S. Sawant Di. Kirillov A. Kuzmin F. S. Bergmann Magnus Wolke Izabela Ciepał A. Goswami Hans Stockhorst Rolf Stassen Rudolf Maier P. Kulessa Wiktor Parol Oleksandr Rundel E. Stephan N.m. Piskunov

subject

Nuclear Theory General Physics and Astronomy 01 natural sciences High Energy Physics - Experiment Nuclear physics 0103 physical sciences ddc:530 FACILITY NEAR-THRESHOLD 010306 general physics NUCLEON Nuclear Experiment Nuclear theory Nuclear Experiment Physics QUASI-FREE 010308 nuclear & particles physics Eta meson Detector COSY Polarization (waves)Near threshold High Energy Physics - Phenomenology Physics::Accelerator Physics Axial symmetry Nucleon

description

Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high degree of the polarized proton beam of COSY, the reaction pp{\to} pp{\eta} has been measured close to threshold to explore the analyzing power Ay. The angular distribution of Ay is determined with the precision improved by more than one order of magnitude with respect to previous results allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q = 15 MeV signaling s wave production with no evidence for higher partial waves. At Q = 72 MeV the data reveals strong interference of P s and P p partial waves and cancellation of (P p) and Ss*Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the {\eta} meson.

year	journal	country	edition	language
2018-01-08

10.1103/physrevlett.120.022002 http://arxiv.org/abs/1709.04547