Observation of Charmed Baryon Production in e+ e- Annihilation

Abrams, G.S. ; Alam, M.S. ; Blocker, C.A. ; et al.
Phys.Rev.Lett. 44 (1980) 10, 1980.
Inspire Record 142743 DOI 10.17182/hepdata.20754

A peak in the pK−π+ and p¯K+π− invariant-mass spectra at 2.285±0.006 GeV/c2 is observed, which is associated with the lowest-lying charmed baryon (Λc). A cross section times branching ratio of 0.037±0.012 nb at Ec.m.=5.2 GeV is measured with a substantial fraction of the events produced with an equal recoiling mass. New measurements of inclusive p and Λ cross sections are also presented, allowing an estimate of the branching ratio B(Λc→pK−π+)=0.022±0.010.

3 data tables

THE TOTAL INCLUSIVE CHARMED LAMBDA CROSS SECTION IS DERIVED FROM THE OBSERVED PRODUCTION RATE VIA THE <P K- PI+> CHANNEL USING THE STEP IN INCLUSIVE PROTON PRODUCTION AT THE CHARMED-BARYON THRESHOLD AND REASONABLE ASSUMPTIONS. THE BRANCHING RATIO (LAMBDA/C+ --> P K- PI+) IS THEN 2.2 +- 1.0 PCT.

ACTUALLY TWICE THE INCLUSIVE ANTI-PROTON CROSS SECTION (EACH BARYON PAIR IS COUNTED TWICE).

EACH BARYON PAIR PRODUCED IS OF COURSE COUNTED TWICE IN THIS CROSS SECTION.


Inclusive Baryon Production in e+ e- Annihilation

Piccolo, M. ; Peruzzi, I. ; Luke, D. ; et al.
Phys.Rev.Lett. 39 (1977) 1503, 1977.
Inspire Record 121395 DOI 10.17182/hepdata.20965

The inclusive production of antiprotons and Λ's in e+e− annihilation has been measured as a function of the c.m. energy in the range 3.7-7.6 GeV. We find that the baryon cross section has a behavior different from the total hadronic production. Our results show a rapid rise in the ratio σp¯σμμ between 4.4 and 5 GeV, consistent with what would be expected from charmed baryon production. Λ¯ production is 10-15% of p¯ production at all energies.

1 data table

NOT INCLUDING SYSTEMATIC ERRORS.