The COMPASS experiment at CERN studies diffractively produced states in the light quark sector with unprecedented statistics. The observation of decaying to ηη in 2008 data with incoming negative pion beam at 190 GeV/c poses the question whether it is produced centrally or formed by the decay of a heavier diffractively produced To decide, a dedicated amplitude analysis which includes different production mechanisms is formulated and compared with one which was used to fit centrally produced resonances including by the WA102 experiment. Unbinned mass‐dependent log‐likelihood fitting methods may serve to solve the ambiguities which are present in binned, mass‐independent partial wave analyses.
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© 2010 American Institute of Physics.
2010
American Institute of Physics