Complex sentence: Neutrinos from a secondary cycle of solar energy generation--i.e., the CNO-neutrinos--are also expected to provide observable events below 1 MeV, that have not yet been observed, due to experimental noise (background).
Split into simpler sentences: Neutrinos from a secondary cycle of solar energy generation--i.e., the CNO-neutrinos--are also expected to provide observable events below 1 MeV. They have not yet been observed due to experimental noise (background).