Purpose of the workshop:
1. A Turning Point operated recently in the Dark Matter research: Warm Dark Matter (WDM) emerged impressively over Cold Dark Matter (CDM) as the leading Dark Matter candidate. WDM solves naturally the problems of CDM and agrees with the observations at small as well as large and cosmological scales. This workshop addresses the last developments in WDM, including the new quantum mechanical framework to galaxy structure reproducing in particular the observed galaxy cores and their sizes. The workshop puts together astrophysical, cosmological and particle WDM, astronomical observations, theory and WDM computational analytical and numerical frameworks which reproduce the observations. The Workshop addresses as well the experimental search for the WDM particle candidates (keV sterile neutrinos).
2. The New Dark Matter Situation Today: Warm Dark Matter (WDM) research is progressing fast, the subject is new and WDM essentially works, naturally reproducing the astronomical observations over all scales: small (galactic) and large (cosmological) scales (LambdaWDM). Astronomical evidence that Cold Dark Matter (LambdaCDM) and its proposed tailored cures do not work at small scales is staggering. Astrophysical constraints including sterile neutrino decays points the sterile neutrino mass m around 2 keV. WDM predictions for EUCLID and PLANCK start to to be available. MARE and an adapted KATRIN experiment could detect a keV sterile neutrino. It will be a fantastic discovery to detect dark matter in a beta decay. A formidable WDM work to perform is ahead of us.
3. History, Context and the CDM crisis: This Workshop is the fourth of a new Chalonge series in Meudon dedicated to Dark Matter. The first Workshop of this series (June 2010) allowed to identify and understand the issues of the serious problems faced by Cold Dark Matter (CDM) to reproduce the galactic (and even cluster of galaxies) observations. The 2010 and 2011 Workshops served as well to verify and better understand the confusion in the CDM research, namely the increasing number of cyclic arguments, and ad-hoc mechanisms introduced in the CDM simulations over most of twenty years, in trying to deal with the CDM small scale crisis: Cusped profiles and overabundance of substructures (too many satellites) are predicted by CDM. In contrast, cored profiles and no such overabundant substructures are seen by astronomical observations. The too many galaxy formation and evolution CDM models are plagued with ever increasing tailoring or fine tuning. On the CDM particle physics side, the situation is no less critical: So far, all the dedicated experimental searches after most of twenty years to find the theoretically proposed CDM particle candidate (WIMP) have failed. The CDM indirect searches (invoking CDM annihilation) to explain cosmic ray positron excesses, are in crisis as well, as wimp annihilation models are plagued with growing tailoring or fine tuning, and in any case, such cosmic rays excesses are well explained and reproduced by natural astrophysical process and sources. The so-called and repeatedealy invoked ‘wimp miracle’ is nothing but being able to solve one equation with three unknowns (mass, decoupling temperature, and annihilation cross section) within wimp models theoretically motivated by SUSY model building twenty years ago (at that time those models were fashionable and believed for many proposals). After more than twenty years -and as often in big-sized science-, CDM research has by now its own internal inertia without reproducing the astronomical observations : growing CDM galaxy simulations involve large super-computers and large number of people working with; CDM particle wimp search involve large and long-time planned experiments, huge number of people, (and huge budgets); one should not be surprised at all, if a fast strategic change would not yet operate in the CDM computer (and super-computer) simulations and wimp research, although its interest would progressively decline.
4. The Workshop addresses the last and fast progresses made in Warm Dark Matter Galaxies in Agreement with Observations. In the tradition of the Chalonge School, an effort of clarification and synthesis will be made by combining in a conceptual framework, theory, analytical, observational and numerical simulation results. The subject will be approached in a threefold way:
(I) Conceptual context: Dark Matter in cosmology and astrophysics: perspective and prospective of the research in the subject: Theory and observations. The emergence of Warm (keV scale) Dark Matter from theory and observations.
(II) Astronomical observations : galaxy structural properties, the universal and non universal properties of galaxies, high quality rotation curves, kinematics, density profiles, gravitational lensing, small and large structures, deep surveys, clusters of galaxies
(III) Computational framework with the equations of physics. Analytical and numerical frameworks. The new important physical ingredient in galaxy structure: quantum mechanics. Classical (non quantum) numerical simulations with Warm Dark Matter and resulting structures. Results versus observations.
Special attention will be payed to the astrophysical understanding of the dark matter problems and its solution, the use of analytic and numerical methods which determine the properties, the density profiles, masses, sizes and evolution, the distribution and the nature of Warm Dark Matter.
- Kinetic theory and the recent progress in solving the Boltzmann-Vlasov equation to obtain the observed universal properties of galaxies.
- N-body numerical simulations whith Warm dark Matter.
- The phase-space density of dark matter.
- Particle model independent analysis of astrophysical dark matter.
- The impact of the mass of the dark matter particle on the small scale structure formation and the choice of the initial conditions.
- The radial profiles and the Dark Matter distribution. Observed galactic cored profiles
- The keV scale Dark Matter (Warm Dark Matter): Observational and theoretical progresses.
- The new quantum mechanical framework to galactic structure. WDM core sizes in agreement with observations.
- Large and small scale structure formation in agreement with observations at small galactic and at large scales.
- The new serious dark matter candidate: Sterile neutrinos at the keV scale.
- Supermassive Black Holes : Theory and Observations.
- The clarifing and unifying WDM framework for stars, galaxies and cosmology.