• A
  • A
  • A
  • ABC
  • ABC
  • ABC
  • А
  • А
  • А
  • А
  • А
Regular version of the site

Article

Evidence for X(3872)→J/ψπ+π− produced in single-tag two-photon interactions

Physical Review Letters. 2020. P. 1-17.
Аушев Т. А., Pakhlov P., Pakhlova G., Попов В. Е., Углов Т. В.

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the position in the final state, exploring the highly virtual photon region. The search is performed in e+e−→e+eJ/ψπ+π−, using 825 fb−1 of data collected by the Belle detector operated at the KEKB e+e− collider. We observe three X(3872) candidates with an expected background of 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ~γγB(X(3872)→J/ψπ+π−) assuming the Q2 dependence predicted by a cc¯ meson model, where −Q2 is the invariant mass-squared of the virtual photon. No X(3915)→J/ψπ+π− candidates are found.