Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism

In this letter, we perform a perturbative analysis by the lightest singular value mD1 of the Dirac mass matrix mD in the type-I seesaw mechanism. A mass relation M1=mD12/|(mν)11| is obtained for the lightest mass M1 of the right-handed neutrino νR1 and the mass matrix of the left-handed neutrinos mν...

Full description

Bibliographic Details
Main Author: Masaki J.S. Yang
Format: Article
Language:English
Published: Elsevier 2023-08-01
Series:Physics Letters B
Online Access:http://www.sciencedirect.com/science/article/pii/S0370269323003957
_version_ 1797776226718318592
author Masaki J.S. Yang
author_facet Masaki J.S. Yang
author_sort Masaki J.S. Yang
collection DOAJ
description In this letter, we perform a perturbative analysis by the lightest singular value mD1 of the Dirac mass matrix mD in the type-I seesaw mechanism. A mass relation M1=mD12/|(mν)11| is obtained for the lightest mass M1 of the right-handed neutrino νR1 and the mass matrix of the left-handed neutrinos mν in the diagonal basis of mD. This relation is rather stable under renormalization because it is gauge-invariant in the SM and associates with the approximate chiral symmetry of νR1.If diagonalization of the Yukawa matrices of leptons Yν,e has only small mixings, the value (mν)11 is close to the effective mass mee of the neutrinoless double beta decay. By assuming mD1≃mu,e≃0.5 MeV, the lightest mass is about M1≳O(100) TeV in the normal hierarchy and M1∼O(10) TeV in the inverted hierarchy. Such a νR1 with a tiny Yukawa coupling yν1∼O(10−5) can indirectly influence various observations.On the other hand, the famous bound of the thermal leptogenesis M1≳109 GeV that requires mD1≳30 MeV seems to be difficult to reconcile with a simple unified theory without a special condition.
first_indexed 2024-03-12T22:47:15Z
format Article
id doaj.art-77e6d0d188ec40f19e10c3d6a3e7fee7
institution Directory Open Access Journal
issn 0370-2693
language English
last_indexed 2024-03-12T22:47:15Z
publishDate 2023-08-01
publisher Elsevier
record_format Article
series Physics Letters B
spelling doaj.art-77e6d0d188ec40f19e10c3d6a3e7fee72023-07-21T04:58:29ZengElsevierPhysics Letters B0370-26932023-08-01843138061Chiral perturbative relation for neutrino masses in the type-I seesaw mechanismMasaki J.S. Yang0Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570, JapanIn this letter, we perform a perturbative analysis by the lightest singular value mD1 of the Dirac mass matrix mD in the type-I seesaw mechanism. A mass relation M1=mD12/|(mν)11| is obtained for the lightest mass M1 of the right-handed neutrino νR1 and the mass matrix of the left-handed neutrinos mν in the diagonal basis of mD. This relation is rather stable under renormalization because it is gauge-invariant in the SM and associates with the approximate chiral symmetry of νR1.If diagonalization of the Yukawa matrices of leptons Yν,e has only small mixings, the value (mν)11 is close to the effective mass mee of the neutrinoless double beta decay. By assuming mD1≃mu,e≃0.5 MeV, the lightest mass is about M1≳O(100) TeV in the normal hierarchy and M1∼O(10) TeV in the inverted hierarchy. Such a νR1 with a tiny Yukawa coupling yν1∼O(10−5) can indirectly influence various observations.On the other hand, the famous bound of the thermal leptogenesis M1≳109 GeV that requires mD1≳30 MeV seems to be difficult to reconcile with a simple unified theory without a special condition.http://www.sciencedirect.com/science/article/pii/S0370269323003957
spellingShingle Masaki J.S. Yang
Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
Physics Letters B
title Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
title_full Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
title_fullStr Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
title_full_unstemmed Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
title_short Chiral perturbative relation for neutrino masses in the type-I seesaw mechanism
title_sort chiral perturbative relation for neutrino masses in the type i seesaw mechanism
url http://www.sciencedirect.com/science/article/pii/S0370269323003957
work_keys_str_mv AT masakijsyang chiralperturbativerelationforneutrinomassesinthetypeiseesawmechanism