RT Journal Article
T1 Cosmology of an Axion-Like Majoron
A1 Cuesta, A. J.
A1 Gómez Santamaría, Mario Emilio
A1 Illana Calero, José Ignacio
A1 Masip Mellado, Manuel
AB We propose a singlet majoron model that defines an inverse seesaw mechanism in the v sector. The majoron phi has a mass m(phi) approximate to 0.5 eV and a coupling to the tau lepton similar to the one to neutrinos. In the early universe it is initially in thermal equilibrium, then it decouples at T approximate to 500 GeV and contributes with just Delta N-eff = 0.026 during BBN. At T = 26 keV (final stages of BBN) a primordial magnetic field induces resonant gamma <-> phi oscillations that transfer 6% of the photon energy into majorons, implying Delta N-eff = 0.55 and a 4.7% increase in the baryon to photon ratio. At T approximate to m(phi) the majoron enters in thermal contact with the heaviest neutrino and it finally decays into v (v) over bar pairs near recombination, setting Delta N-eff = 0.85. The boost in the expansion rate at later times may relax the Hubble tension (we obtain H-0 = (71.4 +/- 0.5) km/s/Mpc), while the processes v (v) over bar <-> phi suppress the free streaming of these particles and make the model consistent with large scale structure observations. Its lifetime and the fact that it decays into neutrinos instead of photons lets this axion-like majoron avoid the strong bounds that affect other axion-like particles of similar mass and coupling to photons.
PB Institute of Physics
YR 2022
FD 2022
LK https://hdl.handle.net/10272/21671
UL https://hdl.handle.net/10272/21671
LA eng
NO Cuesta, A. J., Gómez, M. E., Illana, J. I., & Masip, M. (2022). Cosmology of an axion-like majoron. In Journal of Cosmology and Astroparticle Physics (Vol. 2022, Issue 04, p. 009). IOP Publishing. https://doi.org/10.1088/1475-7516/2022/04/009
NO We would like to thank Mar Bastero, Adrián Carmona, Mikael R. Chala, Miguel Escudero,Javier Olmedo, José Santiago and Samuel Witte for discussions. This workwas partially supported by the Spanish Ministry of Science, Innovation and Universities(PID2019-107844GB-C21/AEI/10.13039/501100011033) and by the Junta de Andalucía(FQM 101, SOMM17/6104/UGR, P18-FR-1962, P18-FR-5057).
DS Repositorio Institucional de la Universidad de Huelva
RD 28 may 2026