Summary report of meeting at CPPM
 
main points that were discussed :
1)The tool COSMOMC or Class
2)The Statistics methods
3)Combinations: which probes?
4) which DE models  to test

Here are  the  main points of the discussion to build a roadmap
-We discussed that CLASS is a good plan to be used  in the future in place of CAMB .
As Julien can be part of the group and proposed support, it is already a good starting point.
In future experiments, we  are also almost convinced that new tools will be developed in new computing framework
both LSST and Euclid will use C++ and Python.  Then starting with CLASS seems a good training and evolution  to prepare future tools.
-we discuss shortly statistic, there was a general consensus that frequentist and bayesien approaches are equivalent, try to keep all open for the moment.
- we discuss what we plan to do and which DE models would be interesting?

Implementing effective field theory in class should be very easy. This could be a short term project within the local expertise. It’s a good check.
Some constraints have already been worked out by the Planck team.  An idea would be to add new datasets.
The tension between RSD and Planck can be something to look at. We can see what happens with the tension with different likelihoods.
Forecast/model/likelihood. Do we need simulations?
- to test that, most of young people as  Alice, Franscisco, Valentina, Stéphane_I (for Ilic…)  had interest in putting their hands soon in CLASS for testing.
There is a clear interest to go fast  on some test cases.
After discussion, it was agreed that we can start by build forecasts on simulated cross-correlation CMB (ISW) LSS (Euclid), with the distribution with z of galaxies. Models for which this would be discriminating?
to develop that in the framework of EFT might be interesting. This can be a first goal to test using CLASS.
the goal is to have a paper is few months.
Other ideas was discussed:
Reionization (other functional forms)+Cosmological Principle tests (isotropy?)
Full wise data: LCDM agrees but not fully
- the fact that we need to build also a strong data experience, with experts from different probes has been also discussed.
Probes that can be developed in our context are CMB, RSD, BAO, Voids, Cluster and WL .
probably a ‘data group' that work out this in detail should be  set.
Technically :
-we discussed to have a communication tool as wiki pages to be set up as soos as possible..propositions will be done.
-we proposed to use the computer facilty cc-in2p3 and to open a dedicated  group with a dedicated name (voted) (Johan.Cohen Tanoudji)
-we will  install COSMOMC  and CLASS ..Stephane.Plaszczynski will prepare and follow  that. He accept to be a support for future users.
-we propose this can be used as a platform  of  test  in particular for CLASS as a baseline .
-we will prepare a mailist (Anne)
-the grid as Dirac has been  also proposed but has been seen as a longer term support if needed.
-We finally discussed next meetings and communication tools.
-We like to  agree on a  ‘video’ system that will be used by all  to help communication (propositions will follow)
-next specific meeting is kept in Montpellier (one day) 9 or 10 april on the advance on CLASS and its  utilisation for our first goal.
- a general meeting will be organized beginning of June.