2005/03/31 by Pei-Hong Gu, Hong Mao
Physics and Astronomy · #Cosmology and Gravitation Theories #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.1016/j.physletb.2005.05.053
published as Phys.Lett. B619 (2005) 226-232 · 12 pages, 3 figures; revised version, accepted for publication in Phys. Lett. B
arxiv created 2005/05/23 · openalex publication_date 2005/06/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In the early universe, as a consequence of U ( 1 ) B – L gauge symmetry-breaking, the so-called B – L cosmic strings are expected to be produced at the breaking scale η B – L according to the Kibble mechanism. The decaying, collapsing closed loops of these strings can release the right-handed neutrinos, whose subsequent decay can contribute to the baryon asymmetry of the universe (BAU), through the “slow death” (SD) process and/or the “quick death” (QD) process. In this Letter, we assume that the decay of the lightest heavy Majorana neutrinos released from the B – L cosmic string loops can produce a baryon asymmetry consistent with the cosmic microwave background (CMB) observations. Considering the fact that both the neutrinoless double beta decay experiment and the cosmological data show a preference for degenerate neutrinos, we give the lower limits for the breaking scale η B – L with the neutrino masses 0.06 eV ⩽ m ¯ = ( m 1 2 + m 2 2 + m 3 2 ) 1 / 2 ⩽ 1.0 eV , where the full possible cases of degenerate neutrinos are included. We obtain η B – L ≳ 3.3 × 10 15 GeV , 5.3 × 10 15 GeV and 9.5 × 10 15 GeV for m ¯ = 0.2 eV , 0.4 eV and 1.0 eV respectively in the SD process, and find the B – L cosmic string has a very small contribution to the BAU in the QD process.