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A Search for the Double-Beta Decay of Xe-136 to an Excited State of Ba-136 with EXO-200

dc.contributor.advisorHall, Carter Ren_US
dc.contributor.authorYen, Yung-Rueyen_US
dc.description.abstractThis thesis presents a search for the two neutrino double beta decay (&beta;&beta;2&nu;) of <super>136</super>Xe to the 0<super>+</super><sub>1</sub> excited state of <super>136</super>Ba using data from the EXO-200 detector collected between 2011 and 2012. The &beta;&beta;2&nu; decay to the excited state is a process that have been observed for other double beta decay nuclei. An observation of this decay would shed some light on the validities of the various nuclear physics models. Located at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM, EXO-200 is a liquid xenon time projection chamber filled with 200 kg of 80.6% isotopically enriched <super>136</super>Xe. The liquid xenon serves both as the decay source and the detection medium. Maximum likelihood fits of the sum energy spectra based on Monte Carlo simulations are used to constrain the number of &beta;&beta;2&nu; decay to the 0<super>+</super><sub>1</sub> excited state of <super>136</super>Ba. A half-life lower limit on this decay of 1.2 &middot; 10<super>23</super> year at 90% C.L is set, still a couple orders of magnitude from our expected theoretical rate of 2.5 &middot; 10<super>25</super> year from the applying the calculated phase space factor and the nuclear matrix element suppressions on the measured &beta;&beta;2&nu; decay to the ground state. A developing analysis using a new energy variable designed specifically for the search of the decay to the excited state is also discussed.en_US
dc.titleA Search for the Double-Beta Decay of Xe-136 to an Excited State of Ba-136 with EXO-200en_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.subject.pqcontrolledNuclear physicsen_US
dc.subject.pqcontrolledParticle physicsen_US
dc.subject.pquncontrolleddouble beta decayen_US
dc.subject.pquncontrolledexcited stateen_US

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