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arXiv · hep-ph/9512374

The $γγ\toπ^0π^0$ and $η\toπ^0γγ$ Transitions in the Extended NJL Model

Johan Bijnens·Ansar Fayyazuddin·Joaquim Prades
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Abstract

We calculate within the Extended Nambu--Jona-Lasinio model the leading in $1/N_c$ contribution to $γγ\toπ^0π^0$ to all orders in the external momenta and quark masses. This result is then combined with the known two-loop Chiral Perturbation Theory and compared with the data and other calculations. A technical difficulty in the same calculation beyond order $p^6$ for $η\toπ^0γγ$ is identified and for this decay results up to order $p^6$ are presented.

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Johan Bijnens, Ansar Fayyazuddin, Joaquim Prades. 1995-12-20. The $γγ\toπ^0π^0$ and $η\toπ^0γγ$ Transitions in the Extended NJL Model. https://doi.org/10.1016/0370-2693(96)00455-8

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