Investigations on states of 20Mg and spallation reaction effects for constraining nuclear physics inputs for X-ray bursts

Show simple item record

dc.contributor.advisor Kanungo, Rituparna
dc.creator Randhawa, Jaspreet
dc.date.accessioned 2017-09-18T14:09:05Z
dc.date.available 2017-09-18T14:09:05Z
dc.date.issued 2017
dc.identifier.other QB464 R36 2017
dc.identifier.uri http://library2.smu.ca/handle/01/27086
dc.description viii, 131 leaves : illustrations (chiefly colored) ; 29 cm
dc.description Includes abstract.
dc.description Includes bibliographical references (leaves 125-131).
dc.description.abstract We present the first observation of a resonance state in the proton drip-line nucleus [superscript 20]Mg. The resonance state was populated via inelastic scattering of [superscript 20]Mg with a solid deuteron target using the IRIS facility stationed at TRIUMF, Canada. Together with the ground state and first excited state, a new resonance state is observed at excitation energy of 3.68 [plus or minus] 0.04 MeV. Based on a comparison of the measured angular distributions to distorted wave Born approximation calculations, the first excited state is consistent with L=2 excitation confirming its spin to be 2+. Similar comparison for new resonance suggests a spin possibility of either (4+) or (2+). The new resonance state lies in the Gamow window and hence puts constraint on the [superscript 18]Ne(2p, gamma)[superscript 20]Mg reaction rate, a possible breakout reaction from hot CNO cycles in X-ray bursts. The new resonance state is higher in energy than expectations based on mirror symmetry to [superscript 20]O. The inferred reaction rate of [superscript 19]Na(p, gamma)[superscript 20]Mg is lower than the previous predictions. The net rate of the [superscript 18]Ne(2p, gamma)[superscript 20]Mg is found to be competitive to beta decay of [superscript 18]Ne only at high densities for it to be a viable breakout path. A comparison to theoretical predictions show that the calculations based on chiral interactions and NN+3N forces fails to explain the observed resonance state. The new data will therefore serve as guidance to benchmark the nuclear structure models and interactions at the drip-line. In a related study of CNO cycles in X-ray bursts, the spallation of the accreted material in the atmosphere of a neutron star has been modelled considering a full cascading destruction process. The results show that the replenishment of CNO elements in a cascading process is minuscule and the CNO abundances are reduced to negligible values. The impact of reduced CNO metallicity on X-ray burst ignition conditions are discussed. en_CA
dc.description.provenance Submitted by Greg Hilliard (greg.hilliard@smu.ca) on 2017-09-18T14:09:05Z No. of bitstreams: 1 Randhawa_Jaspreet_PHD_2017.pdf: 7499265 bytes, checksum: 931e58b6a4e91c2e42dc3335eed8b18d (MD5) en
dc.description.provenance Made available in DSpace on 2017-09-18T14:09:05Z (GMT). No. of bitstreams: 1 Randhawa_Jaspreet_PHD_2017.pdf: 7499265 bytes, checksum: 931e58b6a4e91c2e42dc3335eed8b18d (MD5) Previous issue date: 2017-07-21 en
dc.language.iso en en_CA
dc.publisher Halifax, N.S. : Saint Mary's University
dc.subject.lcc QB464
dc.subject.lcsh Nuclear astrophysics
dc.subject.lcsh Magnesium -- Isotopes
dc.subject.lcsh Spallation (Nuclear physics)
dc.subject.lcsh X-ray bursts
dc.title Investigations on states of 20Mg and spallation reaction effects for constraining nuclear physics inputs for X-ray bursts en_CA
dc.type Text en_CA
thesis.degree.name Doctor of Philosophy in Astronomy
thesis.degree.level Doctoral
thesis.degree.discipline Astronomy and Physics
thesis.degree.grantor Saint Mary's University (Halifax, N.S.)
 Find Full text

Files in this item

 
 

This item appears in the following Collection(s)

Show simple item record

Search DSpace


Browse

My Account