Speaker
Description
Using the data sets above 4.0 GeV collected by the BESIII detector on the Beijing Positron Electron Collider, which corresponds a total integrated luminosity greater than 1.5fb-1, the hexaquark or di-baryon state is searched through e+ e- -> 2(p pbar)and e+ e- -> p p pbar nbar pi- + c.c.. We observed these two final states for the first time, and the Born cross sections ofe+ e- -> 2(p pbar)have been measuredin 23center-of-mass energies ranges between 4.009 and 4.6 GeV. The average Born cross sections of the e+ e- -> p p pbar nbar pi- + c.c.within the energy range of (4.160, 4.380) GeV, (4.400, 4.600) GeV and (4.610, 4.700) GeV are measured. By fitting the invariant mass spectra of pn,pppiand pp, we found that their lineshape areconsistent with the phase space distribution, no significant resonance structures were found.