Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries

Abstract We point out qualitatively different possibilities on the role of CP-conserving processes in generating cosmological particle–antiparticle asymmetries, with illustrative examples from models in leptogenesis and asymmetric dark matter production. In particular, we consider scenarios in which...

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Autores principales:	Avirup Ghosh, Deep Ghosh, Satyanarayan Mukhopadhyay
Formato:	article
Lenguaje:	EN
Publicado:	SpringerOpen 2021
Materias:	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
Acceso en línea:	https://doaj.org/article/f2d01791e41045bc8b156ca1a935fb0a
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spelling	oai:doaj.org-article:f2d01791e41045bc8b156ca1a935fb0a2021-11-28T12:12:06ZRevisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries10.1140/epjc/s10052-021-09848-51434-60441434-6052https://doaj.org/article/f2d01791e41045bc8b156ca1a935fb0a2021-11-01T00:00:00Zhttps://doi.org/10.1140/epjc/s10052-021-09848-5https://doaj.org/toc/1434-6044https://doaj.org/toc/1434-6052Abstract We point out qualitatively different possibilities on the role of CP-conserving processes in generating cosmological particle–antiparticle asymmetries, with illustrative examples from models in leptogenesis and asymmetric dark matter production. In particular, we consider scenarios in which the CP-violating and CP-conserving processes are either both decays or both scatterings, thereby being naturally of comparable rates. This is in contrast to the previously considered CP-conserving processes in models of leptogenesis in different see-saw mechanisms, in which the CP-conserving scatterings typically have lower rates compared to the CP-violating decays, due to a Boltzmann suppression. We further point out that the CP-conserving processes can play a dual role if the asymmetry is generated in the mother sector itself, in contrast to the conventional scenarios in which it is generated in the daughter sector. This is because, the CP-conserving processes initially suppress the asymmetry generation by controlling the out-of-equilibrium number densities of the bath particles, but subsequently modify the ratio of particle antiparticle yields at the present epoch by eliminating the symmetric component of the bath particles through pair-annihilations, leading to a competing effect stemming from the same process at different epochs. We find that the asymmetric yields for relevant particle–antiparticle systems can vary by orders of magnitude depending upon the relative size of the CP-conserving and violating reaction rates.Avirup GhoshDeep GhoshSatyanarayan MukhopadhyaySpringerOpenarticleAstrophysicsQB460-466Nuclear and particle physics. Atomic energy. RadioactivityQC770-798ENEuropean Physical Journal C: Particles and Fields, Vol 81, Iss 11, Pp 1-9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798
spellingShingle	Astrophysics QB460-466 Nuclear and particle physics. Atomic energy. Radioactivity QC770-798 Avirup Ghosh Deep Ghosh Satyanarayan Mukhopadhyay Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
description	Abstract We point out qualitatively different possibilities on the role of CP-conserving processes in generating cosmological particle–antiparticle asymmetries, with illustrative examples from models in leptogenesis and asymmetric dark matter production. In particular, we consider scenarios in which the CP-violating and CP-conserving processes are either both decays or both scatterings, thereby being naturally of comparable rates. This is in contrast to the previously considered CP-conserving processes in models of leptogenesis in different see-saw mechanisms, in which the CP-conserving scatterings typically have lower rates compared to the CP-violating decays, due to a Boltzmann suppression. We further point out that the CP-conserving processes can play a dual role if the asymmetry is generated in the mother sector itself, in contrast to the conventional scenarios in which it is generated in the daughter sector. This is because, the CP-conserving processes initially suppress the asymmetry generation by controlling the out-of-equilibrium number densities of the bath particles, but subsequently modify the ratio of particle antiparticle yields at the present epoch by eliminating the symmetric component of the bath particles through pair-annihilations, leading to a competing effect stemming from the same process at different epochs. We find that the asymmetric yields for relevant particle–antiparticle systems can vary by orders of magnitude depending upon the relative size of the CP-conserving and violating reaction rates.
format	article
author	Avirup Ghosh Deep Ghosh Satyanarayan Mukhopadhyay
author_facet	Avirup Ghosh Deep Ghosh Satyanarayan Mukhopadhyay
author_sort	Avirup Ghosh
title	Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
title_short	Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
title_full	Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
title_fullStr	Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
title_full_unstemmed	Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries
title_sort	revisiting the role of cp-conserving processes in cosmological particle–antiparticle asymmetries
publisher	SpringerOpen
publishDate	2021
url	https://doaj.org/article/f2d01791e41045bc8b156ca1a935fb0a
work_keys_str_mv	AT avirupghosh revisitingtheroleofcpconservingprocessesincosmologicalparticleantiparticleasymmetries AT deepghosh revisitingtheroleofcpconservingprocessesincosmologicalparticleantiparticleasymmetries AT satyanarayanmukhopadhyay revisitingtheroleofcpconservingprocessesincosmologicalparticleantiparticleasymmetries
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Revisiting the role of CP-conserving processes in cosmological particle–antiparticle asymmetries

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