Eur. Phys. J. C (2006) 47: 57-64
https://doi.org/10.1140/epjc/s2006-02561-3

Experimental Physics

Decays of σ, κ, a₀(980) and f₀(980)

Queen Mary, University of London, London, E1 4NS, UK

^* e-mail: D.Bugg@rl.ac.uk

Received: 10 March 2006
Published online: 19 May 2006

Abstract

Ratios of coupling constants for these decays are compared with qq̄ predictions and Jaffe’s q²q̄² model. In both models, the predicted ratio g²(κ→Kπ)/g²(σ→ππ) is much too small. Also, for qq̄, the predicted ratio g²(κ→Kη’)/g²(κ→Kπ) is much larger than observed. Both models fail for g²(f₀→KK)/g²(a₀→KK). This ratio requires that f₀ has a dominant KK component. It arises naturally because the f₀ pole lies very close to the KK threshold, giving its wave function a long KK tail.