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You searched for +publisher:"Michigan State University" +contributor:("Hjorth-Jensen, Morten"). Showing records 1 – 3 of 3 total matches.

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Michigan State University

1. Titus, Luke. Effects of nonlocality on transfer reactions.

Degree: 2016, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2016.

Nuclear reactions play a key role in the study of nuclei away from stability. Single-nucleon transfer reactions involving deuterons provide an exceptional tool to study the single-particle structure of nuclei. Theoretically, these reactions are attractive as they can be cast into a three-body problem composed of a neutron, proton, and the target nucleus.Optical potentials are a common ingredient in reactions studies. Traditionally, nucleon-nucleus optical potentials are made local for convenience. The effects of nonlocal potentials have historically been included approximately by applying a correction factor to the solution of the corresponding equation for the local equivalent interaction. This is usually referred to as the Perey correction factor. In this thesis, we have systematically investigated the effects of nonlocality on (p,d) and (d,p) transfer reactions, and the validity of the Perey correction factor. We implemented a method to solve the single channel nonlocal equation for both bound and scattering states. We also developed an improved formalism for nonlocal interactions that includes deuteron breakup in transfer reactions. This new formalism, the nonlocal adiabatic distorted wave approximation, was used to study the effects of including nonlocality consistently in (d,p) transfer reactions. For the (p,d) transfer reactions, we solved the nonlocal scattering and bound state equations using the Perey-Buck type interaction, and compared to local equivalent calculations. Using the distorted wave Born approximation we construct the T-matrix for (p,d) transfer on 17O, 41Ca, 49Ca, 127Sn, 133Sn, and 209Pb at 20 and 50 MeV. Additionally we studied (p,d) reactions on 40Ca using the the nonlocal dispersive optical model. We have also included nonlocality consistently into the adiabatic distorted wave approximation and have investigated the effects of nonlocality on on (d,p) transfer reactions for deuterons impinged on 16O, 40Ca, 48Ca, 126Sn, 132Sn, 208Pb at 10, 20, and 50 MeV. We found that for bound states the Perry corrected wave functions resulting from the local equation agreed well with that from the nonlocal equation in the interior region, but discrepancies were found in the surface and peripheral regions. Overall, the Perey correction factor was adequate for scattering states, with the exception for a few partial waves. Nonlocality in the proton scattering state reduced the amplitude of the wave function in the nuclear interior. The same was seen for nonlocality in the deuteron scattering state, but the wave function was also shifted outward. In distorted wave Born approximation studies of (p,d) reactions using the Perey-Buck potential, we found that transfer distributions at the first peak differed by 15-35% as compared to the distribution resulting from local potentials. When using the dispersive optical model, this discrepancies grew to \approx 30-50%.…

Advisors/Committee Members: Nunes, Filomena, Hjorth-Jensen, Morten, Zegers, Remco, Voit, Mark, Duxbury, Phil.

Subjects/Keywords: Particles (Nuclear physics); Nuclear optical potentials; Nuclear reactions; Physics; Nuclear physics and radiation; Quantum physics

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APA (6th Edition):

Titus, L. (2016). Effects of nonlocality on transfer reactions. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:3929

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Titus, Luke. “Effects of nonlocality on transfer reactions.” 2016. Thesis, Michigan State University. Accessed September 26, 2020. http://etd.lib.msu.edu/islandora/object/etd:3929.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Titus, Luke. “Effects of nonlocality on transfer reactions.” 2016. Web. 26 Sep 2020.

Vancouver:

Titus L. Effects of nonlocality on transfer reactions. [Internet] [Thesis]. Michigan State University; 2016. [cited 2020 Sep 26]. Available from: http://etd.lib.msu.edu/islandora/object/etd:3929.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Titus L. Effects of nonlocality on transfer reactions. [Thesis]. Michigan State University; 2016. Available from: http://etd.lib.msu.edu/islandora/object/etd:3929

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Michigan State University

2. Whitmore, Kenneth Aaron. Experimental study of 19C via gamma-ray lifetime and knockout measurements.

Degree: 2016, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2016

The nuclear halo is a unique phenomenon occurring at the limit of nuclear stability. Previous studies have established an enhanced low-energy electric dipole strength as a characteristic feature of halo nuclei. Despite such extensive work on the electric response, there is no experimental evidence on the magnetic response of halos. A gamma-ray lifetime measurement has been performed on the one-neutron halo nucleus 19C, which represents the first measurement of a magnetic transition between bound states in a halo nucleus. This measurement also serves as a means to constrain the spin-parities of the states in 19C. The lifetime of the first excited state in 19C has been measured using both the line-shape method and the Recoil Distance Method. The deduced B(M1;3/2+→1/2+) transition strength represents one of the most hindered M1 transitions among light nuclei. The result is compared to large-scale shell model calculations, which predict a strong hindrance due to the degeneracy of the 1s1/2 and 0d5/2 neutron orbitals. The result establishes the M1 hindrance as another feature of halo nuclei which are dominated by s-wave configurations.The one-proton knockout reaction of 20N is used to study the structure of the bound states in 19C as well as the ground state in 20N. Eikonal reaction model calculations are compared to the measured inclusive cross section. The small inclusive cross section indicates the significant difference between the wave functions of the low-lying states of 20N and 19C. The results support the spin-parity assignment of the excited state in 19C obtained from the lifetime measurement. The coupling of the proton 0p1/2 orbital to a 5/2+ core within 20N is suggested from large-scale shell-model calculations performed for the 2− ground state in 20N, indicating that the degeneracy of the 1s1/2 and 0d5/2 orbitals that occurs in 19C does not persist in 20N. Both the lifetime and knockout reaction analyses support the exclusion of a bound 5/2+ state in 19C. The combined results present a consistent picture of the structure of 19C and provide important data to establish trend of the 1s1/2 and 0d5/2 single particle energies for the N=13 isotones.

Description based on online resource;

Advisors/Committee Members: Iwasaki, Hironori, Donahue, Megan, Hjorth-Jensen, Morten, Schmidt, Carl, Spyrou, Artemisia.

Subjects/Keywords: Nuclear physics; Nuclear structure; Ion bombardment; Particles (Nuclear physics); Nuclear physics and radiation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Whitmore, K. A. (2016). Experimental study of 19C via gamma-ray lifetime and knockout measurements. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:4356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Whitmore, Kenneth Aaron. “Experimental study of 19C via gamma-ray lifetime and knockout measurements.” 2016. Thesis, Michigan State University. Accessed September 26, 2020. http://etd.lib.msu.edu/islandora/object/etd:4356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Whitmore, Kenneth Aaron. “Experimental study of 19C via gamma-ray lifetime and knockout measurements.” 2016. Web. 26 Sep 2020.

Vancouver:

Whitmore KA. Experimental study of 19C via gamma-ray lifetime and knockout measurements. [Internet] [Thesis]. Michigan State University; 2016. [cited 2020 Sep 26]. Available from: http://etd.lib.msu.edu/islandora/object/etd:4356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Whitmore KA. Experimental study of 19C via gamma-ray lifetime and knockout measurements. [Thesis]. Michigan State University; 2016. Available from: http://etd.lib.msu.edu/islandora/object/etd:4356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Michigan State University

3. Morris, Titus Dan. Systematic improvements of ab-initio in-medium similarity renormalization group calculations.

Degree: 2016, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2016

The In-Medium Similarity Renormalization Group (IM-SRG) is an ab initio many-body method that has enjoyed increasing prominence in nuclear theory, due to its soft polynomial scaling with system size, and the flexibility to target ground and excited states of both closed- and open-shell systems. Despite many successful applications of the IM-SRG to microscopic calculations of medium-mass nuclei in recent years, the conventional formulation of the method suffers a number of limitations. Key amongst these are i) large memory demands that limit calculations in heavier systems and render the calculation of observables besides energy spectra extremely difficult, and ii) the lack of a computationally feasible sequence of improved approximations that converge to the exact solution in the appropriate limit, thereby verifying that the IM-SRG is systematically improvable. In this thesis, I present a novel formulation of the IM-SRG based on the Magnus expansion. I will show that this improved formulation, guided by intuition gleaned from a diagrammatic analysis of the perturbative content of different truncations and parallels with coupled-cluster theory, allows one to bypass the computational limitations of traditional implementations, and provides computationally viable approximations that go beyond the truncations used to date. The effectiveness of the new Magnus formulation is illustrated for several many-nucleon and many-electron systems.

Description based on online resource;

Advisors/Committee Members: Bogner, Scott K, Dykman, Mark, Hjorth-Jensen, Morten, Nunes, Filomena, Piecuch, Piotr.

Subjects/Keywords: Nuclear physics – Mathematical models; Mass (Physics) – Measurement; Physics; Nuclear physics and radiation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Morris, T. D. (2016). Systematic improvements of ab-initio in-medium similarity renormalization group calculations. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:3864

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Morris, Titus Dan. “Systematic improvements of ab-initio in-medium similarity renormalization group calculations.” 2016. Thesis, Michigan State University. Accessed September 26, 2020. http://etd.lib.msu.edu/islandora/object/etd:3864.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Morris, Titus Dan. “Systematic improvements of ab-initio in-medium similarity renormalization group calculations.” 2016. Web. 26 Sep 2020.

Vancouver:

Morris TD. Systematic improvements of ab-initio in-medium similarity renormalization group calculations. [Internet] [Thesis]. Michigan State University; 2016. [cited 2020 Sep 26]. Available from: http://etd.lib.msu.edu/islandora/object/etd:3864.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Morris TD. Systematic improvements of ab-initio in-medium similarity renormalization group calculations. [Thesis]. Michigan State University; 2016. Available from: http://etd.lib.msu.edu/islandora/object/etd:3864

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.