In our article “The neutrino’s elusive helicity reversal” (PHYSICS TODAY, May 2011, page 40), we wrongly suggested that new, as yet unknown forces might induce neutrinoless double beta decay even if neutrinos are Dirac particles. What we should have said was the following:
Even for practically massless Majorana neutrinos, physics associated with very high mass scales could lead to neutrinoless double beta decay. In that case, new forces that do not connect electrons to neutrinos would lead two neutrons to disintegrate into two protons and two electrons inside a nucleus, exactly as would happen in the case of ordinary weak interactions with massive Majorana neutrinos. Thus new heavy physics could allow neutrinoless double beta decay, and yet neutrinos still could be almost Dirac-like.
We thank Rabindra Mohapatra for pointing this out.
[Editor’s note: With sadness we inform our readers that Maurice Goldhaber died on 11 May 2011.]
