TY - JOUR
T1 - Addressing the Majorana vs. Dirac question with neutrino decays
AU - Balantekin, A. Baha
AU - de Gouvêa, André
AU - Kayser, Boris
N1 - Funding Information:
This work was supported in part by the US National Science Foundation (NSF) Grant No. PHY-1806368 at the University of Wisconsin, in part by the US Department of Energy (DOE) grant # de-sc0010143 at Northwestern University, and in part by the NSF grant PHY-1630782 at both universities. The document was prepared using the resources of the Fermi National Accelerator Laboratory (Fermilab), a DOE, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance , LLC (FRA), acting under Contract No. DE-AC02-07CH11359 .
PY - 2019/2/10
Y1 - 2019/2/10
N2 - The Majorana versus Dirac nature of neutrinos remains an open question. This is due, in part, to the fact that virtually all the experimentally accessible neutrinos are ultra-relativistic. Noting that Majorana neutrinos can behave quite differently from Dirac ones when they are non-relativistic, we show that, at leading order, the angular distribution of the daughters in the decay of a heavy neutrino into a lighter one and a self-conjugate boson is isotropic in the parent's rest frame if the neutrinos are Majorana fermions, independent of the parent's polarization. This result follows from CPT invariance and is independent of the details of the physics responsible for the decay. In contrast, if the neutrinos are Dirac fermions, the angular distribution in such a decay is, in general, not isotropic. We explore the feasibility of using these angular distributions—or, equivalently, the energy distributions of the daughters in the laboratory frame—in order to address the Majorana versus Dirac nature of neutrinos if a fourth, heavier neutrino mass eigenstate reveals itself in the current or next-generation of high-energy colliders, intense meson facilities, or neutrino beam experiments. We also point out how the related decays of a heavy neutrino into charged daughters can be used for the same purpose.
AB - The Majorana versus Dirac nature of neutrinos remains an open question. This is due, in part, to the fact that virtually all the experimentally accessible neutrinos are ultra-relativistic. Noting that Majorana neutrinos can behave quite differently from Dirac ones when they are non-relativistic, we show that, at leading order, the angular distribution of the daughters in the decay of a heavy neutrino into a lighter one and a self-conjugate boson is isotropic in the parent's rest frame if the neutrinos are Majorana fermions, independent of the parent's polarization. This result follows from CPT invariance and is independent of the details of the physics responsible for the decay. In contrast, if the neutrinos are Dirac fermions, the angular distribution in such a decay is, in general, not isotropic. We explore the feasibility of using these angular distributions—or, equivalently, the energy distributions of the daughters in the laboratory frame—in order to address the Majorana versus Dirac nature of neutrinos if a fourth, heavier neutrino mass eigenstate reveals itself in the current or next-generation of high-energy colliders, intense meson facilities, or neutrino beam experiments. We also point out how the related decays of a heavy neutrino into charged daughters can be used for the same purpose.
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U2 - 10.1016/j.physletb.2018.11.068
DO - 10.1016/j.physletb.2018.11.068
M3 - Article
AN - SCOPUS:85059701394
VL - 789
SP - 488
EP - 495
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
ER -