Ponente
Dr.
Darius Jurciukonis
(Vilnius University Institute of Theoretical Physics and Astronomy)
Descripción
Neutrino oscillation experiments showed that neutrinos have tiny but non-zero masses. The seesaw mechanism is the most fruitful explanation of the light neutrino masses and mixings, which connects the tiny neutrino masses with heavy right-handed neutrino masses. After spontaneous symmetry breaking of the
Standard Model gauge group one obtains a $(n_L+n_R)\times(n_L+n_R)$
Majorana mass matrix $M_{\nu}$ for the neutrinos. The mixing between the
$n_R$ right-handed singlet fermions and the neutral parts of the
$n_L$ lepton doublets gives masses to the neutrinos which are of the
size expected from neutrino oscillations.
The diagonalization of the mass matrix gives rise to a split spectrum
consisting of heavy and light states of neutrinos given by $U^T
M_{\nu}U=\mathrm{diag}(m^{\mathrm{light}}_{n_L},m^{\mathrm{heavy}}_{n_R})$. We
analyse two cases of the minimal extension of the Standard Model when
one or two right-handed fields are added to the three left-handed
fields. A second Higgs doublet is included in our model.
We calculate the one-loop radiative corrections to the mass parameters
which produce mass terms for the neutral leptons. In both cases we
numerically analyse light neutrino masses as functions of the heavy
neutrino masses. Parameters of the model are varied to
find light neutrino masses that are compatible with experimental data of
solar $\Delta m^2_\odot$ and atmospheric $\Delta m^2_\mathrm{atm}$
neutrino mass differences for normal and inverted hierarchy. We choose values for the parameters of the tree-level by numerical scans, where we look for the best agreement between computed and experimental neutrino oscillation angles. Different mixing angles between the Higgs fields give different mass spectra of light neutrinos and different distributions of neutral Higgs masses.
Autor primario
Dr.
Darius Jurciukonis
(Vilnius University Institute of Theoretical Physics and Astronomy)
Coautores
Dr.
Andrius Juodagalvis
(Vilnius University Institute of Theoretical Physics and Astronomy)
Dr.
Thomas Gajdosik
(Vilnius University, Physics Faculty)
