English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Recent analyses that include cosmic microwave background (CMB) anisotropymeasurements from the Atacama Cosmology Telescope and the South Pole Telescopehave hinted at the presence of a dark radiation component at more than twostandard deviations. However, this result depends sensitively on the assumptionof an HST prior on the Hubble constant, where $H_0=73.8\pm2.4$ km/s/Mpc at 68%c.l.. From a median statistics (MS) analysis of 537 non-CMB $H_0$ measurementsfrom Huchra's compilation we derive $H_0=68 \pm2.8$ km/s/Mpc at 68% c.l., ingood agreement with the results of a recent analysis of the full Huchra list of$H_0$ measurements. This result is also fully consistent with the value of$H_0=69.7\pm2.5$ km/s/Mpc at 68% c.l. obtained from CMB measurements underassumption of the standard $\Lambda$CDM model. We show that with the MS $H_0$prior the evidence for dark radiation is weakened to $\sim 1.2$ standarddeviations. Parametrizing the dark radiation component through the effectivenumber of relativistic degrees of freedom $N_{eff}$, we find$N_{eff}=3.98\pm0.37$ at 68% c.l. with the HST prior and $N_{eff}=3.52\pm0.39$at 68% c.l. with the MS prior. We also discuss the implications for currentlimits on neutrino masses and on primordial Helium abundances.

The impact of a new median statistics $H_0$ prior on the evidence for dark radiation