Nuclear Theory Seminar

Speaker: Kevin Fossez, NSCL/FRIB at MSU

Title: “Neutron-rich helium isotopes: complex made simple”

Date: Tue, 04 Sep 2018, 11:00 am – 12:00 pm
Type: Seminar
Location: NSCL/FRIB Lecture Hall 1200

We demonstrate that the intricate energy spectrum of neutron-rich helium iso­topes can be straight­for­wardly described by taking advan­tage of the low-energy proper­ties of neutron-neutron interaction and the scale separation that is present in diluted drip­line systems. By using arguments based on the halo effective field theory, we carry out a parameter reduc­tion of the complex-energy config­ura­tion interac­tion frame­work in the spd space, includ­ing resonant and scat­ter­ing states. By constrain­ing the core poten­tial to alpha-n scat­ter­ing phase-shifts and adjust­ing the strength of the spin-singlet central neutron-neutron inter­ac­tion, we re­pro­duce experi­mental ener­gies and widths of 5-8He within tens of keV precision. We predict a parity inver­sion of narrow reso­nances in 9He and show that the ground state of 10He is an s-wave-domina­ted con­figura­tion that could decay through two-neutron emission. This threshold state can be viewed as a “double-halo” struc­ture in an anal­ogy to the atomic 3He(4He)2 trimer.