Abstract
The S-matrix pole structure of the ${\mathrm{J}}^{\mathrm{\ensuremath{\pi}}}$${=(3/2}^{+}$ resonance in $^{5}\mathrm{He}$ is obtained from R-matrix parameters for the system. Two poles are found on different unphysical Riemann sheets. One is a conventional resonance that is primarily responsible for structure in the n-\ensuremath{\alpha} total cross section. The other is a ``shadow'' pole that contributes to the large values of the cross section for the reaction $^{3}\mathrm{H}$(d,n${)\mathrm{}}^{4}$He at low energies. It is the first experimental evidence for the existence of shadow poles in nuclear and particle physics. The two-pole structure of the resonance accounts for different peak positions and widths in the amplitudes for the n-\ensuremath{\alpha} total cross section and for the $^{3}\mathrm{H}$(d,n) reaction cross section.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
