DOI 10.1007/s100529900113
Comprehensive evidence
for a narrow 
state
of mass 2.02GeV/c2
A. Ferrer1 - A.A. Grigoryan2 - V.F. Perepelitsa3,4 - P. Sonderegger4
1 Departamento de Física Atómica Molecular y Nuclear, University of
Valencia and IFIC, Centro Mixto University of Valencia - CSIC,
Avda. Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
2 Theoretical Department, YerPhI, Yerevan Physics Institute,
Br. Alikhanian st. 2, 375036 Yerevan, Armenia
3 ITEP, B. Cheremushkinskaya 25, 117259 Moscow, Russia
4 CERN, CH-1211 Geneva 23, Switzerland
Received: 26 May 1998 / Revised version: 26 March 1999 / Published version: 3 August 1999
Abstract
We review earlier results, and add new evidence, on the existence
of a narrow
state at a mass of 2.02GeV/c2,
which is seen in six different final states, produced via baryon
exchange
in 
interactions at
20 (12)GeV/c.
The data come from a new analysis
of the WA56 experiment done at the CERN Omega spectrometer. The
2020
peak is produced near mid-rapidity, in a kinematic region not
explored
before in baryon exchange processes. Agreement is found with
an earlier
observation of this state, and its absence in a series of unsuccessful
searches is explained. Very low upper limits on mesonic decays
of this state
favor its interpretation as a baryonium candidate.
Copyright Springer-Verlag
