https://doi.org/10.1140/epjc/s10052-019-6728-1
Regular Article - Theoretical Physics
Majorana vs pseudo-Dirac neutrinos at the ILC
1
Instituto de Física Corpuscular (IFIC), CSIC-Universitat de València, Apartado de Correos 22085, 46071, Valencia, Spain
2
Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Peru
* e-mail: jones.j@pucp.edu.pe
Received:
9
November
2018
Accepted:
27
February
2019
Published online:
11
March
2019
Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac pair. An important question is to what extent future colliders will have sensitivity to the splitting between the Majorana components, since this quantity signals the breaking of lepton number and is connected to the light neutrino masses. We consider the production of these neutral heavy leptons at the ILC, where their displaced decays provide a golden signal: a forward–backward charge asymmetry, which depends crucially on the mass splitting between the two Majorana components. We show that this observable can constrain the mass splitting to values much lower than current bounds from neutrinoless double beta decay and natural loop corrections.
© The Author(s), 2019
