Correlation of final state Interaction with the Detection Phase Space

The final state interaction between the emitting particles has been expected to play an important role to discriminate the signal and background channels in the experiment which detects low mass dibaryon. Theoretically this effect is shown most clearly in the invariant mass spectrum which display a narrow peak for the dibaryon decaying particles and a flat distribution for the background particles. But our detailed simulation study indicates that the detection phase space will largely change the shape of the spectra. The calculation for TRIUMF-E772, which is designed to search for d^* dibaryon, shows that the spectra of signal and background become similar to each other and therefore the discrimination is certainly ineffective.