Bibliographic record
Abstract
This master's thesis presents a study of the rare two-neutrino double beta decay (2νββ) of 134 Xe using data from the EXO-200 experiment.The EXO-200 experiment, located at the Waste Isolation Pilot Plant (WIPP) in the United States, is a low-background experiment designed to search for neutrinoless double beta decay (0νββ) using liquid xenon enriched in 136 Xe.However, the EXO-200 experiment also provides an opportunity to study the 2νββ decay of 134 Xe due to its higher concentration (19.1% of its mass is 134 Xe), which is two times larger than that found in nature.The EXO-200 experiment collected data in two phases: Phase I (September 2011 -February 2014) and Phase II (January 2016 -December 2018).This thesis analyzes Phase II data, which is expected to yield better results than Phase I due to detector enhancements.The analysis utilized the energy, topology, and position of particle interactions in the detector to discriminate between signal and background events.The study was extended to several lower energy thresholds to increase detection efficiency.Using the Phase II dataset (exposure: 28.6 kg•yr), the 90% Confidence Level lower limit for the 134 Xe 2νββ half-life is T 2νββ 1/2 > 2.7 × 10 21 yr.This result, while not exceeding the initial Phase II year's result due to energy threshold limitations, is about three times larger than Phase I's.i
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".