Regular Article - Theoretical Physics
Extracting ππ S-wave scattering lengths from cusp effect in heavy quarkonium dipion transitions
Institut für Theoretische Physik II, Rhur-Universität Bochum, 44780, Bochum, Germany
2 Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universität Bonn, 53115, Bonn, Germany
* e-mail: Xiao-Hai.Liu@tp2.ruhr-uni-bochum.de
Published online: 26 January 2013
Charge-exchange rescattering π + π −→π 0 π 0 leads to a cusp effect in the π 0 π 0 invariant mass spectrum of processes with π 0 π 0 in the final state which can be used to measure ππ S-wave scattering lengths. Employing a non-relativistic effective field theory, we discuss the possibility of extracting the scattering lengths in heavy quarkonium π 0 π 0 transitions. The transition ϒ(3S)→ϒ(2S)π 0 π 0 is studied in detail. We discuss the precision that can be reached in such an extraction for a certain number of events.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013