Abstract The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good
description of a wide range of astrophysical and cosmological data. However, there are a …

Astronomical observations reveal a major deficiency in our understanding of physics—the
detectable mass is insufficient to explain the observed motions in a huge variety of systems …

In this work, we construct promising model-building routes towards SO (10) grand unified
theory inflation and examine their ability to explain the recent pulsar timing arrays (PTAs) …

The symmetry breaking of grand unified gauge groups in the early Universe often leaves
behind relic topological defects such as cosmic strings, domain walls, or monopoles. For …

It has recently been pointed out that Gaia is capable of detecting a stochastic gravitational
wave background in the sensitivity band between the frequency of pulsar timing arrays and …

The nature of dark matter is one of the most pressing questions in physics. Yet all our
present knowledge of the dark sector to date comes from its gravitational interactions with …

A series of pulsar timing arrays (PTAs) recently observed gravitational waves at the
nanohertz frequencies. Motivated by this remarkable result, we present a novel class of Pati …

The data recently released by the North American Nanohertz Observatory for Gravitational
Waves provides compelling evidence supporting the existence of a stochastic signal that …

The cold dark-matter model successfully explains both the emergence and evolution of
cosmic structures on large scales and, when we include a cosmological constant, the …

A bstract We show how the generation of right-handed neutrino masses in Majoron models
may be associated with a first-order phase transition and accompanied by the production of …