Gravitational echoes of lepton number symmetry breaking with light and ultralight Majorons

Summary, in English

We formulate a version of the low-scale Majoron model equipped with an inverse seesaw mechanism featuring lepton-number preserving dimension-6 operators in the scalar potential. Contrary to its dimension-4 counterpart, we find that the model can simultaneously provide light and ultralight Majorons, neutrino masses and their mixing, while featuring strong first-order cosmological phase transitions associated to the spontaneous breaking of the lepton number and the electroweak symmetries in the early Universe. We show by a detailed numerical analysis under which circumstances the model can be probed via the primordial gravitational wave spectrum potentially observable at LISA and other planned facilities. We discuss which implications result for collider physics observables, such as scalar trilinear couplings, the scalar mixing angle and the mass of a new CP-even Higgs boson.

• Author: Andrea Addazi; Antonino Marcianò; António P. Morais; Roman Pasechnik; João Viana; Hao Yang
• Department/s: Department of Physics
• Publishing year: 2023-09-01
• Language: English
• Publication/Series: Journal of Cosmology and Astroparticle Physics
• Volume: 2023
• Issue: 9
• Links: http://dx.doi.org/10.1088/1475-7516/2023/09/026
• Document type: Journal article
• Publisher: IOP Publishing
• Topic: Astronomy, Astrophysics and Cosmology; Subatomic Physics
• Keywords: cosmological phase transitions; cosmology of theories beyond the SM; neutrino theory; particle physics - cosmology connection
• Status: Published
• ISBN/ISSN/Other: ISSN: 1475-7516