[Paper Review] Towards the Chalonge Meudon Workshop 2013. Highlights and Conclusions of the Chalonge Meudon workshop 2012: warm dark matter galaxy formation in agreement with observations

Peter L. Biermann, H. J. de Vega+1 more|arXiv (Cornell University)|May 31, 2013

Dark Matter and Cosmic Phenomena8 references6 citations

TL;DR

This paper argues that warm dark matter (WDM) with keV-scale sterile neutrinos is the leading candidate for dark matter, resolving long-standing issues in cold dark matter (CDM) models. It demonstrates that WDM naturally reproduces observed cored galaxy halos, velocity dispersions, and large-scale structure through quantum pressure effects and N-body simulations, with a preferred mass of ~2 keV and strong support from astrophysical and particle physics constraints.

ABSTRACT

Warm Dark Matter(WDM), considerably clarifies and simplifies galaxies and galaxy formation in agreement with observations. WDM essentially works, naturally reproducing the astronomical observations over all scales, small (galactic) as well as large and cosmological scales.Evidence that CDM, CDM+baryons and proposed tailored cures do not work in galaxies is staggering, The Chalonge Meudon Workshop 2012 approached DM in a fourfold coherent way: astronomical observations (galaxy and cluster properties, haloes, rotation curves, density profiles, surface density), LambdaWDM N-body simulations, WDM theory (Boltzmann-Vlasov evolution, halo mass functions, halo models, improved perturbative approachs), quantum WDM fermions forming the observed cores, WDM particle and nuclear physics (sterile neutrinos) and its experimental search. N Amorisco, P Biermann, S Das, H J de Vega, A Kamada, E Ferri(MARE),I D Karanchetsev, W Liao, M Lovell, M Papastergis, N G Sanchez, P Valageas,C Watson, J Zavala,He Zhang present their Highlights.Inside galaxy cores, N-body classical physics simulations are incorrect for WDM because of important quantum effects at such scales.Quantum WDM calculations (Thomas-Fermi) provide galaxy cores, galaxy masses, velocity dispersions and density profiles in agreement with observations.Baryons (16% of DM) are expected to give a correction to pure WDM results. The summary and conclusions by H. J. de Vega and N. G. Sanchez stress that all evidences point to a DM particle mass around 2 keV. Peter Biermann in his live minutes concludes that a few keV sterile neutrino is the most serious DM candidate. MARE -and hopefully KATRIN- could provide a sterile neutrino signal.There is a formidable WDM work to perform ahead of us, these highlights point research directions worthwhile to pursue.Photos of the Workshop are included (Abridged).

Motivation & Objective

• To resolve the small-scale problems of the cold dark matter (CDM) model, such as cusp-core and missing satellite problems.
• To establish warm dark matter (WDM) with keV-scale particles as a viable alternative to CDM, consistent with galaxy-scale and cosmological observations.
• To demonstrate that quantum pressure from WDM fermions naturally produces observed cored dark matter halo profiles.
• To identify keV sterile neutrinos as the most promising WDM particle candidates within minimal extensions of the Standard Model.
• To guide future experimental searches, particularly via beta decay experiments like MARE and KATRIN, for sterile neutrino detection.

Proposed method

• Employing the Thomas-Fermi approximation to model quantum pressure effects in WDM fermions, reproducing observed cored halo density profiles.
• Conducting ΛWDM N-body simulations with keV-scale particles to match observed galaxy and minihalo structures, velocity functions, and scaling laws.
• Applying kinetic theory and Boltzmann-Vlasov evolution to describe the statistical behavior of WDM particles in cosmological settings.
• Using the seesaw mechanism with flavor symmetry (A4 group) to generate keV sterile neutrinos while simultaneously explaining active neutrino masses.
• Integrating astrophysical constraints (rotation curves, surface density, halo size) with particle physics models to bound sterile neutrino mass and mixing angles.
• Evaluating the Dodelson-Widrow production mechanism for sterile neutrinos via neutrino oscillations in the early universe.

Experimental results

Research questions

• RQ1 Can warm dark matter with keV-scale particles resolve the cusp-core and missing satellite problems of the ΛCDM model?
• RQ2 What is the preferred mass range for sterile neutrino dark matter based on astrophysical and cosmological observations?
• RQ3 How do quantum pressure effects from WDM fermions shape the density profiles of galactic dark matter halos?
• RQ4 Can minimal extensions of the Standard Model naturally produce keV sterile neutrinos as viable WDM candidates?
• RQ5 What are the detectable signatures of keV sterile neutrinos in beta decay experiments like MARE and KATRIN?

Key findings

• KeV-scale sterile neutrinos with a mass of approximately 2 keV are strongly favored by both astrophysical observations and theoretical modeling.
• WDM simulations with keV particles successfully reproduce observed galaxy core sizes, velocity dispersions, and the morphology of local minihalos.
• Quantum pressure from WDM fermions, calculated via the Thomas-Fermi approach, naturally produces cored (non-cusped) dark matter halos consistent with rotation curve data.
• The ΛWDM model resolves the small-scale issues of ΛCDM, including the cusp-core and missing satellite problems, without requiring ad-hoc modifications.
• Sterile neutrinos in the 1–4 keV range are consistent with astrophysical constraints and are viable candidates for WDM, with mixing angles ~10⁻⁸ favored by the Dodelson-Widrow mechanism.
• The MARE and KATRIN experiments are identified as prime candidates for detecting keV sterile neutrinos via their potential beta decay signatures.