Time Evolution of Lepton Number Carried by Majorana Neutrinos
| Autor: | Apriadi Salim Adam, Yamato Matsuo, Takuya Morozumi, Nicholas J. Benoit, Yuta Kawamura, Yuya Tokunaga, Naoya Toyota, Yusuke Shimizu |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Physics
Big Bang Particle physics Astrophysics::High Energy Astrophysical Phenomena Operator (physics) High Energy Physics::Phenomenology FOS: Physical sciences General Physics and Astronomy Creation and annihilation operators Lepton number High Energy Physics - Experiment Cosmic neutrino background High Energy Physics - Experiment (hep-ex) MAJORANA High Energy Physics - Phenomenology High Energy Physics - Phenomenology (hep-ph) High Energy Physics::Experiment Neutrino Lepton |
| Zdroj: | Progress of Theoretical and Experimental Physics |
| Popis: | We revisit the time evolution of the lepton family number for a SU(2) doublet consisting of a neutrino and a charged lepton. The lepton family number is defined through the weak basis of the SU(2) doublet, where the charged lepton mass matrix is real and diagonal. The lepton family number carried by the neutrino is defined by the left-handed current of the neutrino family. For this work we assume the neutrinos have Majorana mass. This Majorana mass term is switched on at time $t=0$ and the lepton family number is evolved. Since the operator in the flavor eigenstate is continuously connected to that of the mass eigenstate, the creation and annihilation operators for the two eigenstates are related to each other. We compute the time evolution of all lepton family numbers by choosing a specific initial flavor eigenstate for a neutrino. The evolution is studied for relativistic and nonrelativistic neutrinos. The nonrelativistic region is of particular interest for the Cosmic Neutrino Background predicted from big bang models. In that region we find the lepton family numbers are sensitive to Majorana and Dirac phases, the absolute mass, and mass hierarchy of neutrinos. 20 pages, 7 figures. arXiv admin note: text overlap with arXiv:2004.07664. In v3,references are corrected. In v4, Fig.7 is added. In v6,the typos in Eq.(24),(29-33), and (90) are corrected. In v7,Eq.(20) and an author address are corrected |
| Databáze: | OpenAIRE |
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