On the strong energy dependence of the e^+e^- to ppbar amplitude near threshold

J. Haidenbauer; H. -W. Hammer; Ulf-G. Meißner; A. Sibirtsev

doi:10.1016/j.physletb.2006.10.016

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On the strong energy dependence of the e^+e^- to ppbar amplitude near threshold

J. Haidenbauer·H. -W. Hammer·Ulf-G. Meißner·A. Sibirtsev

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Abstract

We study the energy dependence of the e^+e^- to ppbar cross section close to the two-nucleon threshold, recently reported by the BaBar collaboration. Our analysis also includes the pbarp to e^+e^- data collected by PS170 collaboration and the e^+e^- to NNbar data from the FENICE collaboration. We show that the near-threshold enhancement in the e^+e^- to ppbar cross section can be explained by the final-state interaction between proton and antiproton in the 3S1 partial wave, utilizing the Juelich nucleon-antinucleon model. As a consequence, the strong dependence of the proton electromagnetic form factors on the momentum transfer close to the two-nucleon threshold is presumably also driven by this final-state interaction effect. This result is in line with our previous studies of the near-threshold enhancement of the ppbar invariant mass spectrum seen in the J/Psi to gamma ppbar decay by the BES collaboration and in the B+ to ppbar K+ decay by the BaBar collaboration.

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J. Haidenbauer, H. -W. Hammer, Ulf-G. Meißner, A. Sibirtsev. 2006-06-14. On the strong energy dependence of the e^+e^- to ppbar amplitude near threshold. https://doi.org/10.1016/j.physletb.2006.10.016

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