Abstract
Results of resonance searches in the , , , and invariant mass spectra in proton-proton collisions at are presented. Evidence is shown for the existence of a narrow baryon resonance with mass of and width below the detector resolution of about . The significance is estimated to be above . This state is a candidate for the hypothetical exotic baryon with , , and a quark content of (). At the same mass, a peak is observed in the spectrum which is a candidate for the member of this isospin quartet with a quark content of (). The corresponding antibaryon spectra also show enhancements at the same invariant mass.
- Received 8 October 2003
DOI:https://doi.org/10.1103/PhysRevLett.92.042003
©2004 American Physical Society