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arXiv · 0707.4511

Can the gamma-gamma processes reveal the nature of the sigma ?

G. Mennessier·P. Minkowski·S. Narison·W. Ochs
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Abstract

We reanalyse the gamma-gamma scattering data and conclude that in the mass region below 1 GeV the cross section for gamma-gamma to pi^0-pi^0 can be largely explained by the one pion exchange process with pi-pi rescattering. The radiative width of the sigma is estimated and a model dependent separation into contributions from direct gamma-gamma decay and decay through rescattering is obtained. We confront these findings with QCD spectral sum rule (QSSR) predictions and conclude that the sigma can have a large gluonium component in its wave function.

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G. Mennessier, P. Minkowski, S. Narison, W. Ochs. 2007-08-01. Can the gamma-gamma processes reveal the nature of the sigma ?. https://arxiv.org/abs/0707.4511

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