| Article | |
| Report number | arXiv:2307.15731 |
| Title | Leptogenesis in Parity Solutions to the Strong CP Problem and Standard Model Parameters |
| Author(s) | Carrasco-Martinez, Juanca (UC, Berkeley ; LBL, Berkeley) ; Dunsky, David I. (New York U., CCPP) ; Hall, Lawrence J. (UC, Berkeley ; LBL, Berkeley) ; Harigaya, Keisuke (Chicago U. ; Chicago U., EFI ; Chicago U., KICP ; Tokyo U., IPMU ; CERN) |
| Publication | 2024-06-07 |
| Imprint | 2023-07-28 |
| Number of pages | 41 |
| In: | JHEP 2406 (2024) 048 |
| DOI | 10.1007/JHEP06(2024)048 |
| Subject category | hep-ph ; Particle Physics - Phenomenology |
| Abstract | We study the simplest theories with exact spacetime parity that solve the strong CP problem and successfully generate the cosmological baryon asymmetry via decays of right-handed neutrinos. Lower bounds are derived for the masses of the right-handed neutrinos and for the scale of spontaneous parity breaking, $v_R$. For generic thermal leptogenesis, $v_R \gtrsim 10^{12}$ GeV, unless the small observed neutrino masses arise from fine-tuning. We compute $v_R$ in terms of the top quark mass, the QCD coupling, and the Higgs boson mass and find this bound is consistent with current data at $1 \sigma$. Future precision measurements of these parameters may provide support for the theory or, if $v_R$ is determined to be below $10^{12}$ GeV, force modifications. However, modified cosmologies do not easily allow reductions in $v_R$-- no reduction is possible if leptogenesis occurs in the collisions of domain walls formed at parity breaking, and at most a factor 10 reduction is possible with non-thermal leptogenesis. Standard Model parameters that yield low values for $v_R$ can only be accommodated by having a high degree of degeneracy among the right-handed neutrinos involved in leptogenesis. If future precision measurements determine $v_R$ to be above $10^{12}$ GeV, it is likely that higher-dimensional operators of the theory will yield a neutron electric dipole moment accessible to ongoing experiments. This is especially true in a simple UV completion of the neutrino sector, involving gauge singlet fermions, where the bound from successful leptogenesis is strengthened to $v_R \gtrsim 10^{13}$ GeV. |
| Copyright/License | preprint: (License: CC BY 4.0) publication: © 2024-2025 The Authors (License: CC-BY-4.0), sponsored by SCOAP³ |
Corresponding record in: Inspire
Record created 2023-08-04, last modified 2024-06-12
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