Mirror Dirac Leptogenesis
Kevin Earl, Chee Sheng Fong, Thomas Gregoire, and Alberto Tonero
Abstract We consider a mirror world scenario, in which light Dirac neutrinos are
generated from a seesaw mechanism and leptogenesis occurs at high scale without
violating lepton number. After leptogenesis, the conservation laws of the theory
imply the visible baryon-minus-lepton asymmetry to be equal to the mirror baryonminus-lepton asymmetry. We extend previous work by presenting a detailed study
of this Dirac leptogenesis mechanism by constructing the full set of Boltzmann
Equations (BEs) for both cases of unflavored and flavored regimes. We show that
Z 2 breaking and lepton/mirror lepton flavor effects can be exploited to enhance the
final baryon-minus-lepton asymmetry in our world by several orders of magnitude.
Keywords Leptogenesis · Dirac neutrinos · Mirror world models
1 The Model
We consider a model that, in addition to the SM sector, is characterized by the
presence of a mirror sector with the same structure and field content as the SM. In
addition to SM fields and their mirror copies, we add heavy singlet neutrinos to both
sectors with a Dirac mass term which serves as a portal between the two sectors [1]:
L = i ¯
N Ri /
∂N Ri + i ¯
N
Ri
/
∂N
Ri − M i ¯
N Ri N
Ri
−y αj ¯
l Lα ˜
ΦN Rj − y
αj
¯
l Lα ˜
Φ
N
Rj + h.c.
(1)
The fields l Lα and Φ are SM lepton and Higgs doublets charged under the SM
EW SU (2) L × U(1) Y and ˜
Φ = iσ 2 Φ ∗ , while l
Lα and Φ are mirror lepton and
K. Earl · T. Gregoire · A. Tonero ()
Ottawa-Carleton, Institute for Physics, Carleton University, Ottawa, ON, Canada
e-mail: kearl@physics.carleton.ca; gregoire@physics.carleton.ca
C. S. Fong
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_57
611
Kevin Earl, Chee Sheng Fong, Thomas Gregoire, and Alberto Tonero
Abstract We consider a mirror world scenario, in which light Dirac neutrinos are
generated from a seesaw mechanism and leptogenesis occurs at high scale without
violating lepton number. After leptogenesis, the conservation laws of the theory
imply the visible baryon-minus-lepton asymmetry to be equal to the mirror baryonminus-lepton asymmetry. We extend previous work by presenting a detailed study
of this Dirac leptogenesis mechanism by constructing the full set of Boltzmann
Equations (BEs) for both cases of unflavored and flavored regimes. We show that
Z 2 breaking and lepton/mirror lepton flavor effects can be exploited to enhance the
final baryon-minus-lepton asymmetry in our world by several orders of magnitude.
Keywords Leptogenesis · Dirac neutrinos · Mirror world models
1 The Model
We consider a model that, in addition to the SM sector, is characterized by the
presence of a mirror sector with the same structure and field content as the SM. In
addition to SM fields and their mirror copies, we add heavy singlet neutrinos to both
sectors with a Dirac mass term which serves as a portal between the two sectors [1]:
L = i ¯
N Ri /
∂N Ri + i ¯
N
Ri
/
∂N
Ri − M i ¯
N Ri N
Ri
−y αj ¯
l Lα ˜
ΦN Rj − y
αj
¯
l Lα ˜
Φ
N
Rj + h.c.
(1)
The fields l Lα and Φ are SM lepton and Higgs doublets charged under the SM
EW SU (2) L × U(1) Y and ˜
Φ = iσ 2 Φ ∗ , while l
Lα and Φ are mirror lepton and
K. Earl · T. Gregoire · A. Tonero ()
Ottawa-Carleton, Institute for Physics, Carleton University, Ottawa, ON, Canada
e-mail: kearl@physics.carleton.ca; gregoire@physics.carleton.ca
C. S. Fong
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil
© Springer Nature Switzerland AG 2021
M. B. Paranjape et al. (eds.), Quantum Theory and Symmetries, CRM Series in
Mathematical Physics, https://doi.org/10.1007/978-3-030-55777-5_57
611