A1 Journal article (refereed)
Novel mechanism for primordial perturbations in minimal extensions of the Standard Model (2020)

Karam, A., Markkanen, T., Marzola, L., Nurmi, S., Raidal, M., & Rajantie, A. (2020). Novel mechanism for primordial perturbations in minimal extensions of the Standard Model. Journal of High Energy Physics, 2020(11), Article 153. https://doi.org/10.1007/jhep11(2020)153

JYU authors or editors

Publication details

All authors or editors: Karam, Alexandros; Markkanen, Tommi; Marzola, Luca; Nurmi, Sami; Raidal, Martti; Rajantie, Arttu

Journal or series: Journal of High Energy Physics

ISSN: 1126-6708

eISSN: 1029-8479

Publication year: 2020

Volume: 2020

Issue number: 11

Article number: 153

Publisher: Springer

Publication country: Germany

Publication language: English

DOI: https://doi.org/10.1007/jhep11(2020)153

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/72898

Publication is parallel published: https://arxiv.org/abs/2006.14404


We demonstrate that light spectator fields in their equilibrium can source sizeable CMB anisotropies through modulated reheating even in the absence of direct couplings to the inflaton. The effect arises when the phase space of the inflaton decay is modulated by the spectator which generates masses for the decay products. We call the mechanism indirect modulation and using the stochastic eigenvalue expansion show that it can source perturbations even four orders of magnitude larger than the observed amplitude. Importantly, the indirect mechanism is present in the Standard Model extended with right- handed neutrinos. For a minimally coupled Higgs boson this leads to a novel lower bound on the quartic coupling and constrains the neutrino Yukawas below unity.

Keywords: particle physics; Higgs bosons

Free keywords: cosmology of theories beyond the SM; Higgs physics

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 2

Last updated on 2022-20-09 at 15:33