A Precise Calculation of Delayed Coincidence Selection Efficiency and Accidental Coincidence Rate

TL;DR

This paper introduces an analytical model to accurately evaluate background and signal efficiency in delayed coincidence experiments, validated through simulations and application in Daya Bay neutrino measurements.

Contribution

The paper presents a new analytical approach to precisely calculate delayed coincidence efficiency and accidental background rates, improving systematic uncertainty estimation.

Findings

Model accurately predicts background and efficiency.

Validated with simulations and Daya Bay data.

Reduces uncertainty in neutrino oscillation measurements.

Abstract

A model is proposed to address issues on the precise background evaluation due to the complex data structure defined by the delayed coincidence method, which is widely used in reactor electron-antineutrino oscillation experiments. In this model, the effects from the muon veto, uncorrelated random background, coincident signal and background are all studied with the analytical solutions, simplifying the estimation of the systematic uncertainties of signal efficiency and accidental background rate determined by the unstable single rate. The result of calculation is validated numerically with a number of simulation studies and is also applied and validated in the recent Daya Bay hydrogen-capture based oscillation measurement.