Neutrino Quiz

Peter B. Denton

  1. Solar neutrinos at night:
    Are more neutrinos detected from the Sun during the day or during the night?

  2. Solar neutrino flavor ratios:
    For electron neutrinos from the Sun, the flavor ratio at the Earth is close to 1:1:1. What is the expected flavor ratio for muon neutrinos produced in the Sun?

  3. Distance to point of neutrino last scattering:
    The comoving distance to the photon surface of last scattering is O(10) Gpc. Is the surface of last scattering for neutrinos closer or farther?

  4. Possible solar measurements:
    SNO measured a CC to NC ratio of ~1/3 of solar neutrinos. KamLAND's measurement of reactor neutrinos confirmed the measurement of solar neutrinos by SNO and others. Given KamLAND's measurement, what other values if any could SNO have measured?

  5. Massless neutrinos (Aug 2023):
    Given the current neutrino data, it could be that one of the mass states is massless. The massless state could be ν1. Which of the other two states, if any, could also be massless? (Define the mass states in the usual way: |Ue1|>|Ue2|>|Ue3|.)