Light Sterile Neutrino Effects at theta_13-Sensitive Reactor Neutrino Experiments

TL;DR

This paper investigates how very light sterile neutrinos could influence the measurements of theta_13 in upcoming reactor neutrino experiments, potentially complicating the interpretation of their results.

Contribution

It analyzes the effects of light sterile neutrinos on reactor neutrino experiments and discusses how these effects could impact the measurement of theta_13 and sterile neutrino parameters.

Findings

Sterile neutrinos can affect near and far detector data differently.

The ability to measure sterile neutrino parameters depends on energy spectrum resolution.

Sterile neutrino effects may hinder constraining or measuring theta_13.

Abstract

We study the impact of very light sterile neutrinos (Delta m^2_new around 1 to 10 times 10^(-2) eV^2, sin^2 2theta_new<10^(-1)) on upcoming theta_13-driven reactor antineutrino experiments like Double-CHOOZ and Daya Bay. Oscillations driven by these vales of Delta m^2_new affect data in the near and far detectors differently and hence potentially modify the capability of these experimental setups to constrain and measure sin^2 2theta_13. We find that the hypothesis theta_new different from zero negatively impacts one's ability to either place an upper bound on sin^2 2theta_13 in the advent of no oscillation signal or measure sin^2 2theta_13 if a theta_13-driven signal is observed. The impact of sterile neutrino effects, however, depends significantly on one's ability to measure the recoil positron energy spectrum. If sin^2 2theta_new is larger than 10^(-2), upcoming theta_13-driven reactor antineutrino experiments should be able to measure sin^2 2theta_new and Delta m^2_new, along with sin^2 2theta_13, as long as one is sensitive to distortions in the recoil positron energy spectrum in the near (and far) detectors.