# How can astrophysicists discriminate between pp-chain solar neutrinos and CNO-cycle ones?

Astrophysicists at the Borexino experiment in Italy have recently claimed that they have detected CNO-cycle neutrinos coming from the Sun.

It was the Cover story for the November 26 issue of Nature.

I read the whole Paper, and accompanying editorial, yet unless I missed something, they do not say what makes a CNO-neutrino different from an ordinary pp-neutrino.

They go to great lengths to describe how they excluded all types of background noise, but did not say whether CNO-neutrinos are higher or lower in energy than 'proton-proton chain' neutrinos....

Presumably, CNO neutrinos are higher in energy than pp ones? How many eV or keV?

The dominant CNO neutrino producers are the steps involving $$^{13}\mathrm{N}$$ and $$^{15}\mathrm{O}$$. The peak of the nitrogen spectrum lies in (or at the edge of) a region where the ratio of CNO neutrinos to background is the highest: