TY - JOUR
T1 - Gravity as a portal to reheating, leptogenesis and dark matter
AU - Barman, Basabendu
AU - Cléry, Simon
AU - Co, Raymond
AU - Mambrini, Yann
AU - Olive, Keith A.
N1 - Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - We show that a minimal scenario, utilizing only the graviton as an intermediate messenger between the inflaton, the dark sector and the Standard Model (SM), is able to generate simultaneously the observed relic density of dark matter (DM), the baryon asymmetry through leptogenesis, as well as a sufficiently hot thermal bath after inflation. We assume an inflaton potential of the form V(ϕ) ∝ ϕk about the minimum at the end of inflation. The possibility of reheating via minimal gravitational interactions has been excluded by constraints on dark radiation for excessive gravitational waves produced from inflation. We thus extend the minimal model in several ways: i) we consider non-minimal gravitational couplings — this points to the parameter range of DM masses MN1 ≃ 2–10 PeV, and right-handed neutrino masses MN2 ≃ (5–20) × 1011 GeV, and TRH ≲ 3 × 105 GeV (for k ≤ 20); ii) we propose an explanation for the PeV excess observed by IceCube when the DM has a direct but small Yukawa coupling to the SM; and iii) we also propose a novel scenario, where the gravitational production of DM is a two-step process, first through the production of two scalars, which then decay to fermionic DM final states. In this case, the absence of a helicity suppression enhances the production of DM and baryon asymmetry, and allows a great range for the parameters including a dark matter mass below an MeV where dark matter warmness can be observable by cosmic 21-cm lines, even when gravitational interactions are responsible for reheating. We also show that detectable primordial gravitational wave signals provide the opportunity to probe this scenario for TRH ≲ 5 × 106 GeV in future experiments, such as BBO, DECIGO, CE and ET.
AB - We show that a minimal scenario, utilizing only the graviton as an intermediate messenger between the inflaton, the dark sector and the Standard Model (SM), is able to generate simultaneously the observed relic density of dark matter (DM), the baryon asymmetry through leptogenesis, as well as a sufficiently hot thermal bath after inflation. We assume an inflaton potential of the form V(ϕ) ∝ ϕk about the minimum at the end of inflation. The possibility of reheating via minimal gravitational interactions has been excluded by constraints on dark radiation for excessive gravitational waves produced from inflation. We thus extend the minimal model in several ways: i) we consider non-minimal gravitational couplings — this points to the parameter range of DM masses MN1 ≃ 2–10 PeV, and right-handed neutrino masses MN2 ≃ (5–20) × 1011 GeV, and TRH ≲ 3 × 105 GeV (for k ≤ 20); ii) we propose an explanation for the PeV excess observed by IceCube when the DM has a direct but small Yukawa coupling to the SM; and iii) we also propose a novel scenario, where the gravitational production of DM is a two-step process, first through the production of two scalars, which then decay to fermionic DM final states. In this case, the absence of a helicity suppression enhances the production of DM and baryon asymmetry, and allows a great range for the parameters including a dark matter mass below an MeV where dark matter warmness can be observable by cosmic 21-cm lines, even when gravitational interactions are responsible for reheating. We also show that detectable primordial gravitational wave signals provide the opportunity to probe this scenario for TRH ≲ 5 × 106 GeV in future experiments, such as BBO, DECIGO, CE and ET.
KW - Baryo-and Leptogenesis
KW - Early Universe Particle Physics
KW - Models for Dark Matter
KW - Particle Nature of Dark Matter
UR - http://www.scopus.com/inward/record.url?scp=85144231279&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85144231279&partnerID=8YFLogxK
U2 - 10.1007/JHEP12(2022)072
DO - 10.1007/JHEP12(2022)072
M3 - Article
AN - SCOPUS:85144231279
SN - 1126-6708
VL - 2022
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 12
M1 - 72
ER -