Particle physics today faces the challenge of explaining the mystery of dark matter, the origin
of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent …

Pulsar timing arrays (PTAs) have reported evidence for a stochastic gravitational wave (GW)
background at nanohertz frequencies, possibly originating in the early Universe. We show …

Cosmic inflation provides a window to the highest energy densities accessible in nature, far
beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the …

Abstract Several Pulsar Timing Array (PTA) Collaborations have recently provided strong
evidence for a nHz Stochastic Gravitational-Wave Background (SGWB). Here we investigate …

We obtain a reliable cosmological bound on the axion mass ma by (1) deriving the
production rate directly from pion-pion scattering data, which overcomes the breakdown of …

A bstract Ultra-low mass primordial black holes (PBH), which may briefly dominate the
energy density of the universe but completely evaporate before the big bang …

Many well-motivated extensions of the Standard Model predict the existence of new light
species that may have been produced in the early universe. Prominent examples include …

Modular symmetries offer a dynamic approach to understanding the flavor structure of
leptonic mixing. Using the modular A 4 flavor symmetry integrated in a type-II seesaw, we …

Interacting dark sectors may undergo changes in the number of their relativistic species
during the early universe, due to a mass threshold m (similar to changes in the Standard …

A tight non-linear relation between the X-ray and the optical-ultraviolet (UV) emission has
been observed in active galactic nuclei (AGN) over a wide range of redshift and several …