Measurements of J/ψ and ψ(2S) decays into ΛΛ¯π0 and ΛΛ¯η
Abstract
Using 58×106 J/ψ and 14×106 ψ(2S) events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays J/ψ and ψ(2S)→ΛΛ¯π0 and ΛΛ¯η are measured. For the isospin violating decays, the upper limits are determined to be B(J/ψ→ΛΛ¯π0)<6.4×10-5 and B[ψ(2S)→ΛΛ¯π0]<4.9×10-5 at the 90% confidence level. The isospin conserving process J/ψ→ΛΛ¯η is observed for the first time, and its branching fraction is measured to be B(J/ψ→ΛΛ¯η)=(2.62±0.60±0.44)×10-4, where the first error is statistical and the second one is systematic. No ΛΛ¯η signal is observed in ψ(2S) decays, and B[ψ(2S)→ΛΛ¯η]<1.2×10-4 is set at the 90% confidence level. Branching fractions of J/ψ decays into Σ+π-Λ¯ and Σ¯-π+Λ are also reported, and the sum of these branching fractions is determined to be B(J/ψ→Σ+π-Λ¯+c.c.)=(1.52±0.08±0.16)×10-3.
- Publication:
-
Physical Review D
- Pub Date:
- November 2007
- DOI:
- 10.1103/PhysRevD.76.092003
- arXiv:
- arXiv:0707.1127
- Bibcode:
- 2007PhRvD..76i2003A
- Keywords:
-
- 13.25.Gv;
- 12.38.Qk;
- 14.20.Gk;
- 14.40.Cs;
- Decays of J/psi Upsilon and other quarkonia;
- Experimental tests;
- Baryon resonances with S=0;
- Other mesons with S=C=0 mass<
- 2.5 GeV;
- High Energy Physics - Experiment
- E-Print:
- 7 pages, 10 figures. Phys.Rev.D comments considered