2022 Impact factor 2.7
Hadrons and Nuclei
Eur. Phys. J. A 17, 245-267 (2003)
DOI: 10.1140/epja/i2002-10145-2

Experimental evidence for narrow baryons in the mass range $\mth{1.0 \le M \le 1.46}$ GeV

B. Tatischeff 1, J. Yonnet1, M. Boivin2, M.P. Comets1, P. Courtat1, R. Gacougnolle1, Y. Le Bornec1, E. Loireleux1, M. MacCormick1, F. Reide1 and N. Willis1

1  Institut de Physique Nucléaire, CNRS/IN2P3, F-91406 Orsay Cedex, France
2  Laboratoire National Saturne, CEA/DSM CNRS/IN2P3, F-91191 Gif-sur-Yvette Cedex, France


(Received: 3 July 2002 / Revised version: 28 January 2003 / Published online: 5 June 2003)

The reaction ${\rm pp}\rightarrow {\rm p} {\pi^+}{\rm X}$ was studied at different incident energies around $T_{\rm p} =2$ GeV. Narrow baryonic structures were observed in the missing mass $M_{\rm X}$ and in the invariant mass $M_{\rm p\pi^{+}}$. The masses of these structures are 1004, 1044, 1094, 1136, 1173, 1249, 1277, and 1384 MeV (and possibly 1339 MeV). Some of them were also observed at the same masses in the missing-mass spectra of the dp  $\rightarrow$ ppX reaction although with a weaker signature. Many checks were performed to make sure that these structures were not produced by experimental artifacts. Several narrow small-amplitude peaks, were also extracted using already published photonucleon cross-sections. The small widths of all these results, and the stability of the observed structures, regardless of the experiment, were used to conclude that they are genuine baryons and not merely the consequence of dynamical rescatterings. These baryons cannot be associated with classical q3 quark configurations. We associate them with two colored-quark cluster configurations.

14.20.Gk - Baryon resonances with S=0 .
12.40.Yx - Hadron mass models and calculations.
13.75.Cs - Nucleon-nucleon interactions (including antinucleons, deuterons, etc.).
14.20.Pt - Dibaryons.

© Società Italiana di Fisica, Springer-Verlag 2003