Abstract
We perform a systematic analysis of standard model extensions with an additional anomaly-free gauge $U(1)$ symmetry, to generate Dirac neutrino masses at one loop. Under such symmetry, standard model fields could either transform or be invariant, corresponding to an active $U(1)_X$ or a dark $U(1)_D$ symmetry, respectively. Having an anomaly-free symmetry imposes nontrivial conditions to the number and charges of the unavoidable new states. We perform an intensive scan, looking for non-anomalous solutions for given number of extra chiral fermions. In particular, we concentrate on solutions giving rise to scotogenic neutrino masses via the effective Dirac mass operator. We study the cases where the Dirac mass operator with dimension 5 or 6, is mediated by Dirac or Majorana states, and corresponds to an active $U(1)_X$ or a dark $U(1)_D$ symmetry. Finally, we comment on the solutions featuring no massless chiral fermions.
Highlights
The standard model (SM) of particle physics is a very successful theory, even though it has to be extended in order to account for neutrino masses and dark matter (DM)
Most of the proposals in the literature assume that neutrinos are Majorana in nature, whereas mass generation mechanisms for Dirac type neutrinos are less studied but have recently received increased attention
We look for anomaly-free solutions to SM
Summary
The standard model (SM) of particle physics is a very successful theory, even though it has to be extended in order to account for neutrino masses and dark matter (DM). The studies of one-loop Dirac neutrino masses have typically focused on finding specific anomaly-free solutions of these two kinds of symmetries We present a complete set of relevant anomaly-free solutions to the general problem of the generation of Dirac neutrino masses at one loop with chiral singlet fermions. We look for anomaly-free solutions to SM extensions with an additional Uð1Þ gauge symmetry, giving rise to scotogenic Dirac neutrino masses. We show that the case where the SM is extended with an active Abelian gauge symmetry Uð1ÞX with nonvanishing generation independent charges and a set of N0 singlet chiral fermions shares the same anomaly-free solutions as an Abelian gauge dark symmetry Uð1ÞD with N0 þ 3 singlet chiral fermions having at least three equal charges.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
