The NOvA experiment has submitted its papers “First measurement of electron neutrino appearance in NOvA” and “First measurement of muon-neutrino disappearance in NOvA” for publication in Physical Review Letters and Physical Review D – Rapid Communications, respectively. The papers describe the key aspects of the experiment and the data analysis and formalize the results first presented last August.
Using less than 10 percent of the planned eventual data set, NOvA predicts an observation of 218 muon neutrinos in the NOvA Far Detector in northern Minnesota in the absence of oscillations. However, it observes only 33 muon neutrinos, due to the effect of their oscillation into other types, in agreement with measurements from other experiments.
In two independent analyses, NOvA observes six and 11 electron neutrinos produced from muon neutrino oscillations during the 500-mile-long trip from Fermilab to the NOvA Far Detector. Only one was expected had no oscillations occurred.
These results provide new hints about the pattern of neutrino masses and the possibility that neutrinos behave differently than antineutrinos.
The NOvA collaboration includes 210 scientists and engineers from 43 institutions in seven countries. Preprints of the muon neutrino disappearance and the electron neutrino appearance papers are posted at arXiv.org.
Mark Messier, Indiana University, and Peter Shanahan, Fermilab, are co-spokespersons for NOvA.