ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2007, vol. 644, p. 299-303

Measurement of the η → π+ π- e+ e- decay branching ratio

Bargholtz Chr, Bashkanov M., Bogoslawsky D., Calén H., Cappellaro F., Clement H., Demirörs L., Ekström C., Fransson K., Gerén L., Gustafsson L., Höistad B., Ivanov G., Jacewicz M., Jiganov E., Johansson T., Keleta S., Koch I., Kullander S., Kupść A., Kuznetsov A., Laukhin I. V., Lindberg K., Marciniewski P., Meier R., Morosov B., Oelert W., Pauly C., Pettersson H., Petukhov Y., Povtorejko A., Ruber R. J M Y, Schönning K., Scobel W., Shafigullin R., Shwartz B., Skorodko T., Sopov V., Stepaniak J., Tchernyshev V., Tegnér P. E., Thörngren Engblom P., Tikhomirov V., Turowiecki A., Wagner G. J., Wolke M., Yamamoto A., Zabierowski J., Zartova I., Złomańczuk J.

The reaction p d → 3He η at threshold was used to provide a clean source of η mesons for decay studies with the WASA detector at CELSIUS. The branching ratio of the decay η → π+ π- e+ e- is measured to be (4.3 ± 1.3 ± 0.4) × 10-4. © 2006 Elsevier B.V. All rights reserved.