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Title: Sterile Neutrinos in Cold Climates

Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified, and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10more » TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to sin224 ≤ 0.02 at m2 ~ 0.3 eV2, and the LSND and MiniBooNE allowed regions are excluded at >99% confidence level.« less
Authors:
 [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
1221354
Report Number(s):
FERMILAB-THESIS--2015-17
TRN: US1601313
DOE Contract Number:
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; NEUTRINOS; TIME PROJECTION CHAMBERS; ARGON; NEUTRINO BEAMS; EV RANGE; NEUTRINO OSCILLATION; TEV RANGE 01-10; LIQUIDS; FERMILAB; OPTICAL PROPERTIES; COMPUTER CODES; ELECTRIC POTENTIAL; OPTICAL SYSTEMS; QUANTUM SYSTEMS; ACCELERATORS; COATINGS; DETECTION; FORECASTING; IMPURITIES; INSTALLATION; LOSSES; MIXING RATIO; OPTIMIZATION; SCINTILLATIONS; SIMULATION; SURGES; SAFETY; TESTING; COHERENT PRODUCTION; PARTICLE PROPERTIES; LIQUID SCINTILLATION DETECTORS