A number of challenges to the standard Λ CDM model have been emerging during the past
few years as the accuracy of cosmological observations improves. In this review we discuss …

Sterile neutrinos are natural extensions to the standard model of particle physics in neutrino
mass generation mechanisms. If they are relatively light, less than approximately 10 keV …

ABSTRACT We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope
(HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4 …

We perform a comprehensive cosmological study of the H 0 tension between the direct local
measurement and the model-dependent value inferred from the Cosmic Microwave …

We discuss the ability of a dark fluid becoming relevant around the time of matter-radiation
equality to significantly relieve the tension between local measurements of the Hubble …

Cosmological observations are used to test for imprints of an ultralight axionlike field (ULA),
with a range of potentials V (ϕ)∝[1-cos (ϕ/f)] n set by the axion-field value ϕ and decay …

New early dark energy (NEDE) is a component of vacuum energy at the electron volt scale,
which decays in a first-order phase transition shortly before recombination [F. Niedermann …

Using some of the latest cosmological data sets publicly available, we derive the strongest
bounds in the literature on the sum of the three active neutrino masses, M ν, within the …

The past two decades have seen transformative advances in cosmology and string theory.
Observations of the cosmic microwave background have revealed strong evidence for …

New measurements of the expansion rate of the Universe have plunged the standard model
of cosmology into a severe crisis. In this paper, we propose a simple resolution to the …