IPNS Physics and Theory Seminar : Is the sub-eV active neutrino Dirac or Majorana? (New alternative method to 0-nu-beta-beta decay, by using B^0 (or Upsiol(1s)) –> mu+ mu- nu nu-bar)

Start date and time 2022/08/22 16:00
End date and time 2022/08/22 17:30
Speaker Choong Sun Kim (Yonsei Univ.)
Venue Zoom
Contact tsuna@post.kek.jp
Language English
Web site https://kds.kek.jp/event/43348/


The nature of neutrino, whether it is a Dirac type or Majorana type, may be comprehensively probed using their quantum statistical properties. If neutrino is a Majorana fermion, then by definition it is identical and indistinguishable from the corresponding antineutrino. When a Majorana neutrino and antineutrino are pair produced, the corresponding state has to obey Pauli principle unlike in the Dirac case. We use this property to distinguish between the two cases using the process B^0 → µ− µ+ νµ ¯νµ. We show that the two cases differ dramatically in a special kinematic scenario where, in the rest frame of the parent B meson, the muons fly away back-to-back (i.e. fly with 3-momenta of equal magnitudes but opposite directions), and so do the neutrino and antineutrino.