Speaker
Dr
Peihong GU
(Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany)
Description
In this talk I will introduce a unified picture of Dirac neutrino masses,
baryon asymmetry and dark matter relic density. Specifically, we consider
an $SU(3)'_c\times SU(2)'_L\times U(1)'_Y$ dark
sector, parallel to the $SU(3)_c\times SU(2)_L\times
U(1)_Y$ ordinary sector. The hypercharges, baryon numbers and
lepton numbers in the dark sector are opposite to those in the
ordinary sector. We further introduce three types of messenger
sectors: (i) two or more gauge-singlet Dirac fermions, (ii) two or
more $[SU(2)_L\times SU(2)'_L]$-bidoublet Higgs scalars, (iii)
at least one gauge-singlet Dirac fermion and at least one
$[SU(2)_L\times SU(2)'_L]$-bidoublet Higgs scalar. The lepton
number conserving decays of the heavy fermion singlet(s) and/or
Higgs bidoublet(s) can simultaneously generate a lepton asymmetry in
the $[SU(2)_L]$-doublet leptons and an opposite lepton asymmetry
in the $[SU(2)'_L]$-doublet leptons to account for the
cosmological baryon asymmetry and dark matter relic density,
respectively. The dark proton and/or neutron as the dark matter
particle thus should have a mass about $5\,\textrm{GeV}$. By
integrating out the heavy fermion singlet(s) and/or Higgs
bidoublet(s), we can obtain three light Dirac neutrinos composed of
the ordinary and dark left-handed neutrinos. If a mirror symmetry is
further imposed, our models will not require more parameters than
the traditional type-I, type-II or type-I+II seesaw models.
Primary author
Dr
Peihong GU
(Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany)
