# Reason for borexino pep flux confidence level error

At the TAUP conference in 2011, the Borexino collaboration presented an analysis of electron-neutrino elastic scattering events in their liquid scintillation detector to claim the first observation of neutrinos produced by the pep reaction in the Sun. They quoted a value for the total flux of solar pep neutrinos of 1.6±0.3 (units of 0.01c) and a significance level for the detection of 97%.

I'm wondering is the confidence level justifiable? I'm wondering does anyone know whether it is distributed as a normal distribution and, as result, is the significance level valid?

When quoting a 'detection' of a small signal in a large background you are claiming to have statistically distinguished the signal from zero, so for normal statistics tat would be a claim that the centroid is nearly three times as far from zero as the 1-sigma uncertainty (and $0.3$ is less than a fifth of $1.6$).