Show simple item record

dc.contributor.advisorGarcia, Alejandroen_US
dc.contributor.authorZumwalt, David Williamen_US
dc.date.accessioned2015-09-29T21:28:54Z
dc.date.available2015-09-29T21:28:54Z
dc.date.submitted2015en_US
dc.identifier.otherZumwalt_washington_0250E_14931.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1773/34137
dc.descriptionThesis (Ph.D.)--University of Washington, 2015en_US
dc.description.abstractThis thesis describes developments toward the measurement of the angular correlation between the beta and the antineutrino in the beta decay of $^6$He. This decay is a pure Gamow-Teller decay which is described in the Standard Model as a purely axial vector weak interaction. The angular correlation is characterized by the parameter $a_{\beta\nu}=-1/3$ in the Standard Model. Any deviation from this value would be evidence for tensor components in the weak interaction and would constitute new physics. A new method will be used to measure the parameter $a_{\beta\nu}$ from $^6$He decays, featuring a magneto-optical trap that will measure the beta particle in coincidence with the recoiling $^6$Li daughter ion. This neutral atom trapping scheme provides cold, tightly confined atoms which will reduce systematic uncertainties related to the initial position of the decay. By knowing the initial position of the decay and measuring the time of flight of the recoiling $^6$Li daughter ion in coincidence with the beta, the angular correlation between the beta and the antineutrino can be deduced. We aim to measure $a_{\beta\nu}$ first to the level of $1\%$, and eventually to the $0.1\%$ level, which would represent an order of magnitude improvement in precision over past experiments. Towards this goal, we have designed, built, and successfully tested a liquid lithium target to provide $>2\times10^{10}$ $^6$He atoms/s to a low-background environment, which is the most intense source of $^6$He presently available. This allowed for an additional measurement of the $^6$He half-life ($806.89\pm0.11_{stat}{}^{+0.23}_{−-0.19}{}_{syst}$~ms) to be made with unprecedented precision, resolving discrepancies in past measurements. We have also tested our trapping and detection apparatus and have begun to record preliminary coincidence events.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.rightsCopyright is held by the individual authors.en_US
dc.subject.otherNuclear physics and radiationen_US
dc.subject.otherParticle physicsen_US
dc.subject.otherphysicsen_US
dc.titleDevelopments for the $^6$He $\beta-\bar{\nu}$ angular correlation experimenten_US
dc.typeThesisen_US
dc.embargo.termsOpen Accessen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record