Theory Seminar: Neutron halos in effective field theory
Speaker: Bijaya Acharya, Ohio University
Location: Theory Room
Time: 13:00
In neutron halo nuclei, the neutron distribution extends significantly beyond the region occupied by the nuclear ``core''. Halo effective field theory (Halo-EFT) exploits the consequent separation of scales in order to predict relationships between low-energy observables as a systematic expansion in the ratio of the soft scale associated with the halo neutrons to the hard scale associated with the core. This talk will mainly focus on Coulomb dissociation of neutron halo nuclei in this framework. For Carbon-19, I will discuss the reduced transition probability for E1 excitation of the bound-state neutrons to the continuum up to N2LO in the Halo-EFT expansion. By comparing the prediction with data from RIKEN, accurate results for Carbon-19's one-neutron separation energy and asymptotic normalization coefficient are extracted. Good agreement between data and Halo-EFT is also found for the longitudinal momentum distribution of Carbon-19. I will discuss matter radii of two-neutron halos in Halo-EFT framework and present our analysis of Carbon-22 matter radius data, which we use as input to constrain Carbon-21 and Carbon-22 energies. I will then move on to Coulomb dissociation of two-neutron halos. In the unitary limit, we discover a simple scaling of the E1 excitation spectrum with the three-body binding energy. Results for Coulomb dissociation of Lithium-11 and Carbon-22 will be presented.