Regular Article - Experimental Physics
Measurement of the η–η′ mixing angle in π − and K − beams with the GAMS-4π Spectrometer
Institute for High Energy Physics, Nauka Sq. 1, Protvino, Russia
* e-mail: Vladimir.Samoylenko@ihep.ru
Revised: 25 July 2013
Published online: 24 October 2013
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.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013