Abstract
Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state with a significance of . The mass and width are measured to be and , respectively, where the first error is statistical and the second systematic. The Born cross section for and the fraction of it attributable to in the range are also determined. We interpret this state as the neutral partner of the four-quark candidate .
- Received 17 June 2015
DOI:https://doi.org/10.1103/PhysRevLett.115.112003
© 2015 American Physical Society