Hagen, Philipp Robert: Effective Field Theory for Halo Nuclei. - Bonn, 2014. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-35269
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-35269,
author = {{Philipp Robert Hagen}},
title = {Effective Field Theory for Halo Nuclei},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2014,
month = mar,

note = {We investigate properties of two- and three-body halo systems using effective field theory. If the two-particle scattering length a in such a system is large compared to the typical range of the interaction R, low-energy observables in the strong and the electromagnetic sector can be calculated in halo EFT in a controlled expansion in R/|a|. Here we will focus on universal properties and stay at leading order in the expansion.
Motivated by the existence of the P-wave halo nucleus 6He, we first set up an EFT framework for a general three-body system with resonant two-particle P-wave interactions. Based on a Lagrangian description, we identify the area in the effective range parameter space where the two-particle sector of our model is renormalizable. However, we argue that for such parameters, there are two two-body bound states: a physical one and an additional deeper-bound and non-normalizable state that limits the range of applicability of our theory. With regard to the three-body sector, we then classify all angular-momentum and parity channels that display asymptotic discrete scale invariance and thus require renormalization via a cut-off dependent three-body force. In the unitary limit an Efimov effect occurs. However, this effect is purely mathematical, since, due to causality bounds, the unitary limit for P-wave interactions can not be realized in nature. Away from the unitary limit, the three-body binding energy spectrum displays an approximate Efimov effect but lies below the unphysical, deep two-body bound state and is thus unphysical. Finally, we discuss possible modifications in our halo EFT approach with P-wave interactions that might provide a suitable way to describe physical three-body bound states.
We then set up a halo EFT formalism for two-neutron halo nuclei with resonant two-particle S-wave interactions. Introducing external currents via minimal coupling, we calculate observables and universal correlations for such systems. We apply our model to some known and suspected halo nuclei, namely the light isotopes 11Li, 14Be and 22C and the hypothetical heavy atomic nucleus 62Ca. In particular, we calculate charge form factors, relative electric charge radii and dipole strengths as well as general dependencies of these observables on masses and one- and two-neutron separation energies. Our analysis of the62Ca system provides evidence of Efimov physics along the Calcium isotope chain. Experimental key observables that facilitate a test of our findings are discussed.},

url = {https://hdl.handle.net/20.500.11811/6047}

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