2–6 Sept 2019
Europe/Zurich timezone

$\Delta N_{\rm eff} \neq \Delta N_{\rm eff}$ -- Dark Radiation vs. Decaying Dark Matter vs. Equivalent Neutrinos

2 Sept 2019, 15:49
11m
Talk Dark Matter and Astroparticle Physics Parallel Sessions: Dark Matter and Astroparticle (C.A.R.L., H08)

Speaker

Janina Renk (Stockholm University)

Description

The number of extra relativistic degrees of freedom, $\Delta N_{\rm eff}$ , has recently received attention as a possible way to alleviate the Hubble tension. Non-standard values, i.e. $\Delta N_{\rm eff} \neq 0$, can arise from different physical origins, such as the presence of additional ultra-relativistic species or non-standard values of the temperature ratio between photons and standard model neutrinos. In this talk I will show how these distinct origins of $\Delta N_{\rm eff}$ yield different observable features by altering predictions for the CMB and matter power spectra as well as primordial element abundances from BBN in different ways. To obtain meaningful results a consistent treatment and implementation of BSM likelihoods and models is essential. I will discuss how these issues can be addressed with the new CosmoBit module of the Global and Modular Beyond-the-StandardModel Inference Tool (GAMBIT). 

Primary authors

Janina Renk (Stockholm University) Pat Scott Felix Kahlhoefer (RWTH Aachen) Joakim Edsjo (Stockholm University)

Presentation materials