ar X iv : 0 80 4 . 25 30 v 1 [ he p - ph ] 1 6 A pr 2 00 8 S -
نویسنده
چکیده
We report on a dispersion relation for the γγ → (ππ)I S-wave in isospin I emphasizing the low energy region. The f0(980) signal that emerges in γγ → ππ is also discussed. Our results could be used to distinguish between different ππ isoscalar S-wave parameterizations. We also calculate the width of the σ resonance to γγ and obtain the value Γ(σ → γγ) = (1.68±0.15) KeV. Finally, we elaborate on the size of the f0(980) coupling to ππ and show that its smallness compared to the KK̄ one is not related to the OZI rule.
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