Evidence for X(3872) → J/Ψπ+π- Produced in Single-Tag Two-Photon Interactions

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e(+) e(-) -> e(+)e(-) J/Psi pi(+)pi(-), using 825 fb(-1) of data collected by the Belle detector operated at the KEKB e(+) e(-) - collider. We observe three X(3872) candidates, where the expected background is 0.11 +/- 0.10 events, with a significance of 3.2 sigma. We obtain an estimated value for (Gamma) over tilde (gamma gamma) B(x(3872) -> j/Psi pi(+)pi(-)) assuming the Q(2) dependence predicted by a c (c) over bar meson model, where -Q(2) is the invariant mass squared of the virtual photon. No X(3915) -> J/Psi pi(+)pi(-) candidates are found.

Automated summary

The study reports the first evidence of X(3872) production in two-photon interactions by tagging either the electron or the positron, with a significance of 3.2 sigma. The estimated value for (Gamma) over tilde (gamma gamma) B(x(3872) -> j/Psi pi(+)pi(-)) was obtained based on the predicted Q(2) dependence by a c (c) over bar meson model, with no X(3915) -> J/Psi pi(+)pi(-) candidates found.