Search for Tetraneutron by Pion Double Charge Exchange Reaction at J-PARC

Abstract

Tetraneutron (${}^{4}n$) has come back in the limelight, because of recent observation of a candidate resonant state at RIBF. We propose to investigate the pion double charge exchange (DCX) reaction, i.e. ${}^4\mathrm{He}({\pi }^{-},{\pi }^{+})$, as an alternative way to populate tetraneutron. An intense ${\pi }^{-}$ beam with the kinetic energy of ~850 MeV, much higher than that in past experiments at LAMPF and TRIUMF, will open up a possibility to improve the experimental sensitivity of the formation cross section, which will be much smaller than hitherto known DCX cross sections such as ${}^9\mathrm{Be}({\pi }^{-},{\pi }^{+}{)}^9\mathrm{He}(g.s.)$.

Comments: 4 pages, 1 figure; proceedings of the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016), Kyoto, Japan, 25-30 July 2016