A TEST OF CHIRAL PERTURBATION-THEORY FROM THE MEASUREMENT OF THE DECAY KS-]GAMMA-GAMMA

Journal article

Data from NA31 experiment at CERN have been used to measure the decay KS → γγ. From 69 candidate events of the type K0 → γγ, 52 events can be attributed to KL → γγ and one event is expected from background processes. The ratio of the relative decay widths R = Γ(KS → γγ) Γ(KL → γγ) is measured to be R = 2.2 ± 1.0(stat.) ± 0.3(syst.) ± 0.2(ext.) where the external systematic error is due to the experimental uncertainty in the branching ratio of the decay KL → γγ. This translates into a branching ratio of BR(KS → γγ) = (2.2 ± 1.1) × 10-6. If these data are combined with the published data from an earlier data taking period with the same experiment, the ratio R is determined to be R = 2.35 ± 0.75(stat.) ± 0.4(syst.) + 7.5 · (1 - BR(KL → γγ) 5.86 × 10-4) where the last term accounts for the dependence on the measured KL → γγ branching ratio. The corresponding branching ratio for KS → γγ is BR(KS → γγ) = (2.4 ± 0.9) × 10-6. The measurement is a sensitive test of chiral perturbation theory and in good agreement with theoretical predictions. © 1995.

Authors: Barr, G; Buchholz, P; Cundy, D; Doble, N; Gatignon, L

• Publication status: Published
• Journal: Physics Letters B
• Volume: 351
• Issue: 4
• Pages: 579-584
• Publication date: 1995-06-01
• DOI: 10.1016/0370-2693(95)00442-N
• ISSN: 0370-2693