Speakers
Description
Unveiling chiral-odd dimeson generalized distribution amplitudes
S. Bhattacharya, R. Boussarie, B. Pire, L. Szymanowski
Chiral-odd generalized distribution amplitudes which are the crossed matrix elements from chiral-odd quark GPDs in a meson contain valuable information on the transversity (or tensor) structure of mesons.
They are up to now inaccessible to experimental investigation. We study a new reaction which allows to separate them from known quantities: exclusive electron positron annihilation into two back to back pion pairs of moderate invariant mass, through two photon exchange : $e^- e^+ \to \gamma^* \gamma^* \to (\pi \pi)_1 (\pi \pi)_2$. In the case of the production of two charged dimeson ($\pi^+\pi^0$) and ($\pi^-\pi^0$), this process interferes with a process with a single photon $e^- e^+ \to \gamma^* \to (\pi^+\pi^0) (\pi^-\pi^0)$. A direct measure of this interference is possible through the study of charge-conjugation odd observables such as the forward - backward asymmetry of the $\pi^+\pi^0$ cross section. Such studies may be performed at BES III or BELLE 2 facilities.
