Throwing away antimatter via neutrino oscillations during the reheating era

Abstract

The simplest possibility to explain the baryon asymmetry of the Universe is to assume that radiation is created asymmetrically between baryons and anti-baryons after the inflation. We propose a new mechanism of this kind where CP-violating flavor oscillations of left-handed leptons in the reheating era distribute the lepton asymmetries partially into the right-handed neutrinos while net asymmetry is not created. The asymmetry stored in the righthanded neutrinos is later washed out by the lepton number violating decays, and it ends up with the net lepton asymmetry in the Standard Model particles, which is converted into the baryon asymmetry by the sphaleron process. This scenario works for a range of masses of the right-handed neutrinos while no fine-tuning among the masses is required. The reheating temperature of the Universe can be as low as O(10) TeV if we assume that the decays of inflatons in the perturbative regime are responsible for the reheating. For the case of the reheating via the dissipation effects, the reheating temperature can be as low as O(100) GeV.

Neutrino Oscillation and Matter-antimatter Asymmetry of Universe

“…We have shown that the matter-antimatter asymmetry of our Universe If the inflaton perturbatively decays also to lepton with flavor violation, the lepton asymmetry needs T R ≳ 10 8 GeV [1]. As recently shown in [2], if the reheating completes via the dissipation effect, where the scattering between the inflaton and the thermal plasma significantly generates the radiation, the reheating temperature can be even smaller. In particular, in the ALP inflation [14][15][16], ( In the low-scale ALP inflation, the abundance of the light scalar particles can be significantly altered due to the Bunch-Davies distribution formed during the inflation [17][18][19][20][21].…”

Scale and quality of Peccei-Quinn symmetry and weak gravity conjectures

“…To avoid the proton decays, one can introduce a Z 2 symmetry under which SM leptons are odd but the baryons are even or vise versa. In this case, the baryon asymmetry may be correctly obtained from neutrino oscillation with the higher dimensional term (3.24) [84,85] and also the quark oscillation could be important via the baryon-number-violating but baryon-parity-conserving operator [86]. Lastly, let us mention the confinement of SO(N ).…”

What if ALP dark matter for the XENON1T excess is the inflaton

“…In the case of 1 TeV M 2 ≈ M 3 10 6 GeV, the right amount of baryon asymmetry may be generated via resonant leptogenesis [73,74], while vanilla leptogenesis [75] is difficult because of the low reheating temperature T R ∼ 10 6 GeV. When M 2,3 ∼ 1 -100 GeV, on the other hand, the baryon asymmetry may be obtained from flavor oscillations of the lefthanded leptons which are produced from the inflaton decays or scatterings [76,77]. If the ALP-lepton derivative couplings and y ν ij are flavor-violating, i.e.…”

“…This active lepton oscillation effect in the ALP inflation scenario was studied by solving kinetic equations for lepton density matrices in ref. [77]. It was found that the produced asymmetry is of the neutrino Yukawa matrix squared, O((y ν ) 2 ), at the leading order, since the leptons can be efficiently produced from the ALP-lepton interaction that is assumed to be flavor-violating, and the tuning between M 1 and M 2 is not needed.…”