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arXiv · 1810.03669

Dispersive analysis of the $γγ^{*} \to ππ$ process

Igor Danilkin·Marc Vanderhaeghen
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Abstract

We present a theoretical study of the $γγ^{*} \to π^+π^-, π^0π^0$ processes from the threshold through the $f_2(1270)$ region in the $ππ$ invariant mass. We adopt the Omnès representation in order to account for rescattering effects in both s- and d-partial waves. For the description of the $f_0(980)$ resonance, we implement a coupled-channel unitarity. The constructed amplitudes serve as an essential framework to interpret the current experimental two-photon fusion program at BESIII. They also provide an important input for the dispersive analyses of the hadronic light-by-light scattering contribution to the muon's anomalous magnetic moment.

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Igor Danilkin, Marc Vanderhaeghen. 2019-01-20. Dispersive analysis of the $γγ^{*} \to ππ$ process. https://doi.org/10.1016/j.physletb.2018.12.047

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