Measurement of neutrino mixing angle Θ13 in the Daya Bay Reactor Neutrino Experiment

Neutrino oscillations have been observed in experiments measuring solar, atmospheric, accelerator and reactor neutrinos. The phenomenon can be described by three mixing angles and three phases. The values of two mixing angles θ₁₂ and θ₂₃ have been pinned down while the value of θ₁₃ was poorly known. The Daya Bay Reactor Antineutrino Experiment was designed to measure \sin²2θ₁₃ with a sensitivity of 0.01 or better by detecting antineutrinos from nuclear reactors with multiple identically designed detectors at different baselines. Antineutrinos were identified by inverse beta decay \bar{\nu}_e + p \rightarrow e⁺ + n in 20~tons of Gadolinium-doped liquid scintillator which served as both target and detector. A search for \bar{\nu}_e deficits, a process which would manifest a nonzero value of the θ₁₃ mixing angle, was performed. Between December 2011 and Feb 2012, 55 days of data were collected. During this time, 80376 and 10416 electron antineutrino candidates were detected with 1545 and 515 expected background events at the near sites and the far site respectively. A rate-only analysis supports neutrino flavor oscillation with \sin²2θ₁₃ = 0.0936\pm0.0172 in a 2-neutrino mixing framework.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Ngai, Wah Kai

Contributors dc:contributor

• Peng, Jen-Chieh
• Thaler, Jonathan J.
• Willenbrock, Scott S.
• Kwiat, Paul G.

• neutrino
• Mixing
• angle
• theta13
• daya bay
• reactor

Statement dc:rights

• Copyright 2012 Wah Kai Ngai

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/34258

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/34258