Chronology of Milestone Events in Particle Physics - BIAGI 1983C
Chronology of Milestone Events in Particle Physics

BIAGI 1983C

Biagi, S.F. et al.
Observation of a Narrow State at 2.46 GeV/ c2 - A Candidate for the Charmed Strange Baryon A+
Phys. Lett. 122B (1983) 455;

Reprinted in
Gluons and Heavy Flavours, La Plagne (1983) 341.

Abstracts
A narrow state has been observed in the reaction - Be (K-++ ) + X in an experiment at the CERN SPS hyperon beam. At 2.46 GeV/c2 the effective (K-++) mass distribution shows an excess of 82 events above a background estimated to be 147, corresponding to a statistical significance of more than 6 standard deviations. The positive charge of the observed final state, which has strangeness-2, suggests the interpretation as a Cabibbo favored decay of the charmed strange baryon, A+ [quark content (csu)]. The cross section times branching ratio is measured to be B = (5.3 2.0) b/(Be nucleus) for x > 0.6. The invariant production cross section is described by
E d3/d p3 propto (1 - x)(1.7 0.7)exp[-(1.1+0.7-0.4)p2T].

Accelerator CERN-SPS Detectors SPEC

Related references
See also
H. J. Burckhart, Ph.D.Thesis, Universitat Heidelberg (1983);
M. Bourquin et al., Nucl. Phys. B153 (1979) 13;

Reactions
  Be K 2+ X 135 GeV (Plab) mass
  Be XI/C+! X 135 GeV (Plab) p, pt, cs
  XI/C+! K 2+

Particles studied
  XI/C+ ex, qn, mass

Record comments
First evidence for the c(2460)+.
    
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