Daya Bay neutrino oscillation progress based on neutron captured on hydrogen

TL;DR

The Daya Bay experiment has improved measurements of neutrino oscillation parameters by analyzing neutron captures on hydrogen, providing more precise data on the nonzero neutrino mixing angle $ heta_{13}$.

Contribution

This paper presents the latest improved measurement of $ heta_{13}$ using neutron captures on hydrogen, with enhanced statistics and systematic control, complementing previous gadolinium-based analyses.

Findings

Confirmed nonzero $ heta_{13}$ with higher precision.

Reduced systematic uncertainties in neutron capture analysis.

Enhanced statistical significance of neutrino oscillation results.

Abstract

The Daya Bay reactor neutrino experiment is the first experiment that measured a nonzero value for the $\theta_{13}$ neutrino mixing angle in 2012. Antineutrinos from six 2.9 GW$_{\text{th}}$ reactors are detected in eight functionally identical antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. The near-far arrangement of antineutrino detectors allows for a relative measurement by comparing the observed antineutrino rates at various baselines. In 2014, the Daya Bay experiment reported an independent measurement of the nonzero neutrino oscillation parameter $\theta_{13}$, utilizing the data set of neutron captured on hydrogen ($n$H) with distinct systematic uncertainties from the data set of neutrons captured on gadolinium, and has been improving this measurement since then. The latest result of the Daya Bay $n$H neutrino oscillation analysis with improved statistics and systematic control is presented.