Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves

Abstract We discuss the damping of inflationary gravitational waves (GW) that re-enter the horizon before or during an epoch, where the energy budget of the universe is dominated by an unstable right handed neutrino (RHN), whose out of equilibrium decay releases entropy. Starting from the minimal St...

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Main Authors: Maximilian Berbig, Anish Ghoshal
Format: Article
Language:English
Published: SpringerOpen 2023-05-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP05(2023)172
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author Maximilian Berbig
Anish Ghoshal
author_facet Maximilian Berbig
Anish Ghoshal
author_sort Maximilian Berbig
collection DOAJ
description Abstract We discuss the damping of inflationary gravitational waves (GW) that re-enter the horizon before or during an epoch, where the energy budget of the universe is dominated by an unstable right handed neutrino (RHN), whose out of equilibrium decay releases entropy. Starting from the minimal Standard Model extension, motivated by the observed neutrino mass scale, with nothing more than 3 RHN for the Seesaw mechanism, we discuss the conditions for high scale leptogenesis assuming a thermal initial population of RHN. We further address the associated production of potentially light non-thermal dark matter and a potential component of dark radiation from the same RHN decay. One of our main findings is that the frequency, above which the damping of the tensor modes is potentially observable, is completely determined by successful leptogenesis and a Davidson-Ibarra type bound to be at around 0.1 Hz. To quantify the detection prospects of this GW background for various proposed interferometers such as AEDGE, BBO, DECIGO, Einstein Telescope or LISA we compute the signal-to-noise ratio (SNR). This allows us to investigate the viable parameter space of our model, spanned by the mass of the decaying RHN M 1 ≳ 2.4 × 10 8 GeV ⋅ 2 × 10 − 7 eV / m ~ 1 $$ {M}_1\gtrsim 2.4\times {10}^8\textrm{GeV}\cdot \sqrt{2\times {10}^{-7}\textrm{eV}/{\tilde{m}}_1} $$ (for leptogenesis) and the effective neutrino mass parameterizing its decay width m ~ 1 $$ {\tilde{m}}_1 $$ < 2.9 × 10 −7 eV (for RHN matter domination). Thus gravitational wave astronomy is a novel way to probe both the Seesaw and the leptogenesis scale, which are completely inaccessible to laboratory experiments in high scale scenarios.
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spelling doaj.art-50dfa60b2cdf4fdbbdbfdf0cb2ee73fc2023-08-27T11:05:32ZengSpringerOpenJournal of High Energy Physics1029-84792023-05-012023513810.1007/JHEP05(2023)172Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational wavesMaximilian Berbig0Anish Ghoshal1Bethe Center for Theoretical Physics und Physikalisches Institut der Universitt BonnInstitute of Theoretical Physics, Faculty of Physics, University of WarsawAbstract We discuss the damping of inflationary gravitational waves (GW) that re-enter the horizon before or during an epoch, where the energy budget of the universe is dominated by an unstable right handed neutrino (RHN), whose out of equilibrium decay releases entropy. Starting from the minimal Standard Model extension, motivated by the observed neutrino mass scale, with nothing more than 3 RHN for the Seesaw mechanism, we discuss the conditions for high scale leptogenesis assuming a thermal initial population of RHN. We further address the associated production of potentially light non-thermal dark matter and a potential component of dark radiation from the same RHN decay. One of our main findings is that the frequency, above which the damping of the tensor modes is potentially observable, is completely determined by successful leptogenesis and a Davidson-Ibarra type bound to be at around 0.1 Hz. To quantify the detection prospects of this GW background for various proposed interferometers such as AEDGE, BBO, DECIGO, Einstein Telescope or LISA we compute the signal-to-noise ratio (SNR). This allows us to investigate the viable parameter space of our model, spanned by the mass of the decaying RHN M 1 ≳ 2.4 × 10 8 GeV ⋅ 2 × 10 − 7 eV / m ~ 1 $$ {M}_1\gtrsim 2.4\times {10}^8\textrm{GeV}\cdot \sqrt{2\times {10}^{-7}\textrm{eV}/{\tilde{m}}_1} $$ (for leptogenesis) and the effective neutrino mass parameterizing its decay width m ~ 1 $$ {\tilde{m}}_1 $$ < 2.9 × 10 −7 eV (for RHN matter domination). Thus gravitational wave astronomy is a novel way to probe both the Seesaw and the leptogenesis scale, which are completely inaccessible to laboratory experiments in high scale scenarios.https://doi.org/10.1007/JHEP05(2023)172Baryo- and LeptogenesisEarly Universe Particle PhysicsCosmology of Theories BSMNeutrino Interactions
spellingShingle Maximilian Berbig
Anish Ghoshal
Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
Journal of High Energy Physics
Baryo- and Leptogenesis
Early Universe Particle Physics
Cosmology of Theories BSM
Neutrino Interactions
title Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
title_full Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
title_fullStr Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
title_full_unstemmed Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
title_short Impact of high-scale Seesaw and Leptogenesis on inflationary tensor perturbations as detectable gravitational waves
title_sort impact of high scale seesaw and leptogenesis on inflationary tensor perturbations as detectable gravitational waves
topic Baryo- and Leptogenesis
Early Universe Particle Physics
Cosmology of Theories BSM
Neutrino Interactions
url https://doi.org/10.1007/JHEP05(2023)172
work_keys_str_mv AT maximilianberbig impactofhighscaleseesawandleptogenesisoninflationarytensorperturbationsasdetectablegravitationalwaves
AT anishghoshal impactofhighscaleseesawandleptogenesisoninflationarytensorperturbationsasdetectablegravitationalwaves