Work

Precision calculation of N eff with neutrino direct simulation Monte Carlo

Year: 2025

Type: article

Abstract: Neutrino direct simulation Monte Carlo ( ν DSMC ) is a Monte Carlo method for solving the neutrino Boltzmann equation in the early Universe, designed to track the evolution of cosmic neutrinos across a wide range of cosmological scenarios. We develop a complete ν DSMC solver that consistently incorporates the effects of the electron mass, three-flavor neutrino oscillations, and finite-temperature QED corrections to the thermodynamics of the electromagnetic plasma. As a first application, we perform a high-precision calculation of neutrino decoupling in the standard cosmological model and obtain N eff = 3.0439 ± 0.0006 , in excellent agreement with state-of-the-art results.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/21gr-4xgd

Authors: Oleksii Ihnatenko, Maksym Ovchynnikov

Institutions: Taras Shevchenko National University of Kyiv, European Organization for Nuclear Research

Language: English

Topic: Neutrino Physics Research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: European Commission, Horizon 2020 Framework Programme, HORIZON EUROPE Framework Programme, HORIZON EUROPE Marie Sklodowska-Curie Actions

Award: Revealing New Physics Through Primordial Neutrinos