19-21 September 2023
Europe/Berlin timezone

A global analysis of decaying cosmological ALPs

21 Sep 2023, 16:30
Nachrichtentechnik-Hörsaal (NTI) (KIT)

Nachrichtentechnik-Hörsaal (NTI)


Engesserstraße 5, 76131 Karlsruhe


Tomas Gonzalo (KIT)


Axion-like particles (ALPs) decaying before the time of recombination can have strong implications in a range of cosmological and astrophysical observations. In this talk I present a global analysis of a model of decaying ALP, focusing specifically on their coupling to photons. Exploiting the multidisciplinary nature of the GAMBIT framework, we combine state-of-the-art calculations of the irreducible ALP freeze-in abundance, primordial element abundances (including photodisintegration through ALP decays), CMB spectral distortions and temperature anisotropies, and astrophysical constraints from supernovae and stellar cooling. Most notable among the interesting results that I will present are a definite lower bound on the ALP mass, and a surprising improvement of the fit to the primordial abundances compared to vanilla ΛCDM.

Primary author

Presentation Materials

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