Jun 2 – 7, 2019
Carnegie Mellon University
America/New_York timezone

## Dispersive analysis of the $\gamma \gamma^* \to \pi\pi, \pi\eta$ processes

Jun 3, 2019, 5:30 PM
30m
Rangos 1

### Speaker

Oleksandra Deineka (JGU Mainz)

### Description

We present a theoretical analysis of $\gamma\gamma^* \to \pi^0\pi^0, \pi^+\pi^-$ and $\gamma\gamma^*\to\pi^0\eta$ processes within the energy range from threshold to 1.4 GeV and the low spacelike virtualities of photons. The Omn`es representation is adopted in order to account for rescattering effects in both s- and d-partial waves, except for $a_2(1320)$, which is approximated as a Breit-Wigner resonance. For the description of the $a_0(980)$ and $f_0(980)$ resonances, 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. As a natural continuation of our work we also provide a discussion on the double-virtual processes, since they serve as an important input for the dispersive analyses of the hadronic light-by-light scattering contribution to the muon’s anomalous magnetic moment.

[1] I. Danilkin, O. Deineka and M. Vanderhaeghen, Phys.Rev.D 96, no. 11, 114018 (2017)
[2] O. Deineka, I. Danilkin and M. Vanderhaeghen, arXiv:1808.04117 [hep-ph]
[3] I. Danilkin and M. Vanderhaeghen, Phys.Lett.B 789, 366 (2019)