The NNbar and multihadron production at the threshold at VEPP2000

A study of hadron production at the nucleon-antinucleon threshold has been performed with the CMD-3 detector at the VEPP-2000 e⁺e⁻ collider. A very fast rise with an about 1 MeV width has been observed in the e⁺e⁻→ pp̅ cross section. A sharp drop in the e⁺ e⁻→ 3(π⁺π⁻) cross section has been con?rmed and found to have a width of less than 2 MeV, in agreement with the observed fast rise of the e⁺e⁻→ pp̅ cross section. For the ?rst time a similar sharp drop is demonstrated in the e⁺e⁻→ K⁺ K⁻π⁺π⁻ cross section. The behavior of the e⁺e⁻→ 3(π⁺ π⁻), K⁺ K⁻π⁺π⁻ cross sections cannot be explained by an interference of any resonance amplitude with continuum, therefore this phenomenon cannot be due to a narrow near-threshold resonance. No such structure has been observed in the e⁺e⁻→ 2(π⁺π⁻) cross section.