Measurement of the η–η′ mixing angle in π − and K − beams with the GAMS-4π Spectrometer
- 70 Downloads
The η–η′ mixing angle has been measured with the GAMS-4π spectrometer in a high statistics experiment. η′ and η mesons were generated with charge–exchange reactions in 32.5 GeV/c π − and K − beams. Using both π − and K − beams allows the study of the |η q 〉 and |η s 〉 components of the meson wave function. The cross section ratio at t′=0 (GeV/c)2 in the π − beam is R π (η′/η)=0.54±0.04, and the mixing angle ϕ P =(36.3±1.0)∘. For the K − beam the ratio is R K (η′/η)=1.27±0.15. It was found that the gluonium content in η′ is sin2 ϕ G =0.17±0.07.
KeywordsDifferential Cross Section Pseudoscalar Meson Cross Section Ratio Meson Wave Function Gluon Content
We are grateful to Professors A.K. Likhoded and A.V. Luchinsky for useful discussions.
This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.
- 1.T. Feldmann. arXiv:hep-ph/9907491
- 7.F. De Fazio, M.R. Pennington. arXiv:hep-ph/0007260
- 8.F. Ambrosino et al. arXiv:0906.3819 [hep-ph]
- 9.M.-C. Chang et al. arXiv:1203.3399 [hep-ex]
- 10.R. Aaij et al. CERN-PH-EP-2012-022 Google Scholar
- 20.A.A. Lednev, Preprint IHEP 93-153 Google Scholar
- 21.S.V. Donskov, V.A. Kachanov, V.M. Kutin et al., IHEP 68–46 (preprint) (in Russian) Google Scholar
- 22.R.K. Bock (ed.), Formulas and Methods in Experimental Data Evaluation, vol. 3 (Eur. Phys. Soc., Mulhouse, 1984) Google Scholar