Odd and even partial waves of ηπ−ηπ− and η′π−η′π− in π−p→η(′)π−pπ−p→η(′)π−p at 191 GeV/c

• Published in: Physics letters. B Vol. 740
• Main Authors: Adolph, C., Andrieux, V., Bedfer, Y., Boer, M, Burtin, E., Capozza, L., Curiel, Q., Ferrero, A., d'Hose, N., Kunne, F., Levillain, M., Magnon, A., Marchand, C., Neyret, D., Platchkov, S., Wollny, H., Compass, Collaboration
• Format: Journal Article
• Language: English
• Published: Elsevier 01.01.2015
• Subjects: Nuclear Experiment; Physics
• ISSN: 0370-2693
• DOI: 10.1016/j.physletb.2014.11.058

Exclusive production of ηπ− and ηπ− has been studied with a 191 GeV/c π− beam impingingon a hydrogen target at COMPASS (CERN). Partial-wave analyses reveal different odd/even angularmomentum (L) characteristics in the inspected invariant mass range up to 3 GeV/c2. A striking similaritybetween the two systems is observed for the L = 2, 4, 6 intensities (scaled by kinematical factors) and therelative phases. The known resonances a2(1320) and a4(2040) are in line with this similarity. In contrast,a strong enhancement of ηπ− over ηπ− is found for the L = 1, 3, 5 waves, which carry non-q¯q quantumnumbers. The L = 1 intensity peaks at 1.7 GeV/c2 in ηπ− and at 1.4 GeV/c2 in ηπ−, the correspondingphase motions with respect to L =2 are different.