Tensions in the Standard Model of Cosmology

This topical collection seeks to bring together cutting-edge research on the growing set of observational tensions that challenge the standard ΛCDM model of cosmology. These include both long-standing problems and emerging anomalies across multiple cosmological probes and key parameters, such as the Hubble tension, weak lensing measurements of the S8 parameter, hints of a dynamical dark energy sector, and inconsistencies between cosmological constraints on the total neutrino mass and results from oscillation experiments.

We welcome contributions that engage with the following questions:

• What is the physical origin of these tensions, and do they point to a breakdown of the standard cosmological framework?

• How can we develop and test well-motivated extensions to ΛCDM that address multiple anomalies in a consistent and predictive manner?

• To what extent do observational and theoretical systematics impact our interpretation of current data, and how can we critically reassess their robustness?

We are particularly interested in works at the intersection of cosmology, astrophysics, and fundamental physics that identify key obstacles through multidisciplinary approaches spanning theoretical model building, data analysis, and methodological innovation. As the volume and precision of cosmological data continue to grow with missions such as Euclid, JWST, DESI, LIGO/Virgo/KAGRA, and the Simons Observatory, achieving a clear understanding of the standard model of cosmology (and any viable extensions) has become an increasingly urgent scientific goal.

List of Topics covered:

• Cosmic distance ladder,

• Supernova cosmology

• Hubble tension — Early and Late time solutions;

• Hubble tension — Systemtics

• Measurements of the S8 parameter

• Hints for dynamical dark energy

• Neutrino Cosmology

• Cosmic Tensions and dark matter, dark energy, and inflation models

• Numerical methods for cosmology

Keywords: Cosmology, Cosmic Tensions, Hubble tension, Measurements of S8, Large-Scale Structure, Neutrinos, Dynamical Dark Energy