https://doi.org/10.1140/epjc/s10052-017-4987-2
Regular Article - Theoretical Physics
Leptoquark mechanism of neutrino masses within the grand unification framework
1
Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB), University of Split, Ruđera Boškovića 32, 21000, Split, Croatia
2
Department of Physics, University of Ljubljana, Jadranska 19, 1000, Ljubljana, Slovenia
3
Jožef Stefan Institute, Jamova 39, P. O. Box 3000, 1001, Ljubljana, Slovenia
* e-mail: dorsner@fesb.hr
Received:
10
May
2017
Accepted:
10
June
2017
Published online:
21
June
2017
We demonstrate the viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are 
–
and 
–
, respectively. We consider two distinct regimes for the LQ masses in our analysis. The first regime calls for very heavy LQs in the loop. It can be naturally realized with the – scenarios when the LQ masses are roughly between 
and 
GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the – scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the – scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of SU(5). We furthermore discuss several possible embeddings of this mechanism in SU(5) and SO(10) gauge groups.
© The Author(s), 2017
