Revisiting the 'LSND anomaly' II: critique of the data analysis

TL;DR

This paper critically examines the LSND anomaly, arguing that the statistical significance of the observed excess of antielectron neutrino interactions is lower than previously claimed, challenging its interpretation as evidence for sterile neutrinos.

Contribution

It provides a detailed critique of the LSND data analysis, suggesting that the anomaly's significance is overestimated and may not indicate new physics beyond the standard neutrino model.

Findings

Re-evaluation reduces the anomaly significance to no more than 2.3 sigma.

Questions the LSND estimate of antielectron neutrino interactions and associated errors.

Suggests the need for revised background estimates in LSND data analysis.

Abstract

This paper, together with a preceding paper, questions the so-called 'LSND anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from 0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light 'sterile' neutrino. In a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration's estimate of the number of antielectronneutrino interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the 'LSND anomaly' is not larger than 2.3 sigma.