2023/08/14 by A. Bolaños, Bolaños-Carrera, A., M. Guiot-Lomelí +3
Engineering · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle accelerators and beam dynamics
paper · pdf · doi:10.48550/arxiv.2308.07493
openalex publication_date 2023/08/14 · openalex created_date 2023/08/17 · openalex updated_date 2026/07/28
The one-loop contribution of scalar and vector leptoquarks (LQs) to the electromagnetic properties (NEPs) of massive Dirac neutrinos is presented via an effective Lagrangian approach, with emphasis on the effective neutrino charge radius (NCR), which has never been calculated and is obtained by the background field formalism in a Yang-Mills-like scenario for gauge LQs. Analytical results for nonzero neutrino mass are presented in terms of both Feynman-parameter integrals and Passarino-Veltman scalar functions, which can be useful to obtain the NEPs of heavy neutrinos, out of which approximate expressions are obtained for light neutrinos. For the numerical analysis we concentrate on the only renormalizable scalar and vector LQ representations that do not need extra symmetries to forbid tree-level proton decay. Constraints on the parameter space consistent with current experimental data are then discussed and it is found that the LQ representations \widetildeR2 and U1 could yield the largest contributions to the NEPs provided that they have couplings to both left- and right-handed neutrinos of the order of O(1). For a LQ mass of 1.5 TeV, the magnetic dipole moment (MDM) of the tau neutrino can be of the order of 10-9 μB, whereas its neutrino electric dipole moment (EDM) can reach values as high as 10-20-10-19 ecm. On the other hand, the NCR can reach values up to 10-35 cm2 regardless of the neutrino flavor and even in the absence of right-handed neutrinos. In the latter scenario, the EDM vanishes and the contribution to neutrino MDM would be negligible, of the order of 10-14 μB for the tau neutrino, whereas those for the muon and electron neutrinos would be about two and seven orders of magnitude smaller, respectively. Our estimates could be severely suppressed due to a possible suppression of the LQ coupling constants.