Abstract
A neutral structure in the system around the mass threshold is observed with a statistical significance greater than in the processes and at and 4.257 GeV in the BESIII experiment. The structure is denoted as . Assuming the presence of a resonance, its pole mass and width are determined to be and , respectively. The Born cross sections are measured to be at 4.226 GeV and at 4.257 GeV. The ratio of decay rates is determined to be , consistent with no isospin violation in the process, .
- Received 17 September 2015
DOI:https://doi.org/10.1103/PhysRevLett.115.222002
© 2015 American Physical Society