The NNbar and multihadron production at the threshold at VEPP2000
Budker Institute of Nuclear Physics, SB RAS, Novosibirsk, 630090, Russia
2 Novosibirsk State University, Novosibirsk, 630090, Russia
3 Novosibirsk State Technical University, Novosibirsk, 630092, Russia
4 University of Victoria, Victoria, BC, Canada V8W 3P6
5 Lebedev Physical Institute RAS, Moscow, 119333, Russia
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Published online: 17 June 2019
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.
© The Authors, published by EDP Sciences, 2019
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