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The ZEN project

The ZEN project aims to address open questions in fundamental cosmology, specifically the dark matter/dark energy sector and the primordial universe. The project involves a collaboration between the ANR program CPPM and the FCPPL program, with a focus on statistical methods and data analysis to obtain results. This project builds upon the work already done by the Chinese and French groups.

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The ZEN project

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  1. The ZEN project A. Tilquin Centre de Physique des Particules de Marseille

  2. Determination of cosmological parameters • Scientific Goal: Address open questions of fundamental cosmology: dark matter/dark energy sector and primordial universe • Main people involve: ANR program CPPM Alain Bonnissent, Anne Ealet, Dominique Fouchez, Lei Sun, Diane Talon-Esmieu, Charling. Tao CEA Philippe.Brax, Jean Batiste Melin, Christophe.Yèche, Dominique.Yvon, Nathalie Palanque-Delabrouille, Alexandre.Réfrégier, Jim.Rich CPT Christian. Marinoni, Pierre Taxil, Jean-Marc Virey, Stefan. Linden LAL Francois Couchot, Olivier Perdereau, L. Perotto, S. Plaszczynski , C. Rosset FCPPL: Franco-China-Particle-Physics-Laboratory program IHEP/PKU/NAOC/Tsinghua U/Beijing Normal U. ZHANG XinMin, ZHAO Gongbo, QIAN Zuxuan, XIA Junqing, FAN Zuhui, LI Hong, Zhu Zhonghong, QIN Bo, DENG Jinsong, CHAO Wu , ZHOU Xu , WANG Xiaofeng To change: View -> Header and Footer

  3. Plan • Few words about cosmology and dark energy • How to characterize dark energy • Statistical method and datagrid • Results already obtained by the Chinese and French groups (ESR and Euchina) • Prospective To change: View -> Header and Footer

  4. Some words about cosmology • Cosmology based on: Homogenous and isotropic Universe General relativity: G = 8GT Energy content:  = /c Equation of state: w(z)=p/ Matter (m) : w =0 Radiation (r) : w = 1/3 Cosmological cste (): w=-1 Dark energy (X) : w(z) T = m + r + X (rc=10-29 g/cm3) To change: View -> Header and Footer

  5. Dark energy or cosmological constant caracterized by reduce density: W =r/rc For a flat Universe: Some words about dark energy • In 1998, the Supernova Cosmology Project and High-z team shown that high red-shift supernovae are fainter than expected: a new energy component is needed. Z Definition:W=r/rc(rc=10-29 g/cm3) To change: View -> Header and Footer

  6. From observations to the Concordance Model SNe Ia CMB(WMAP) Universe is mainly dark LSS ~70% DE and ~25% DM. a 2006 status Our Univers is accelerating To change: View -> Header and Footer

  7. Phenomenological aspect • From where this acceleration is coming from ? • Two main classes of theory/model : Particle physics or Gravity ? Gravity Particle physics General relativity Modification of gravity Long range force induced by light fieldmodification of the gravity+violation of the équivalence principle: Tensor-scalar theory, cameleon model, runaway dilaton …(w<-1) Acceleration is due to new fields weekly couple to gravitation: CDM, quintessence, topological default, Chaplygin Gaz…. In all cases: New fields are needed Dark energy can always been described by an effective equation of state: w=p/ = w0+waz/(1+z) New dominant fields over matter at z=0 Matière standard g Matière standard g   New fields are non dominant ->expansion rate is unchanged. Coupling with photons-> apparent modif. of the dynamic: oscillations photon/axions in B -> Differents type of gravitons, masseless or not : extra dimensions, multi brane, multigravite, brane induced gravity, simulated gravity… négative energy… Matière standard g Matière standard g(i) New non dominant fields. A a To change: View -> Header and Footer

  8. How to extract w0,wa? Degeneracies between parameters imply multi-probes analysis sensitive to complementary quantities: Snapshot at ~400,000 yr, viewed from z=0 CMB Angular diameter distance to z~1000 Growth rate of structure (from ISW) Supernovae Standard candle Luminosity distance Evolution of dark matter perturbations Cosmic Shear Angular diameter distance Growth rate of structure Evolution of dark matter perturbations Cluster counts Angular diameter distance Growth rate of structure Baryon Wiggles Angular diameter distance To change: View -> Header and Footer

  9. Physical parameters • Important number of parameters, cosmological and astrophysical • b/m density for baryon/matter •  density for neutrino’s • T curvature density • H Hubble constant, • ns spectral index, •  reionisation optical depth • 8 normalization for CMB, WL and BAO. • ms normalization for SNIa. • yhe Helium fraction • w0,wa Equation of state…. • Efficient statistical tools needed: • Bayesian statistic and MCMC : Chinese and astrophysicist choice • Frequentist statistic and datagrid : French and particle physicist choice To change: View -> Header and Footer

  10. Statisitcal method • Statistic based on 2(i,w0,wa,…) • Minimum using the gradient method: 2/i=0 • Numerical resolution and iterative: • Error computation: • Contour: Solving the equation 2 = 2min +s2 Marginalization obtained by minimization: 2(w0,wa) = 2min(i | w0,wa) • The contour is constructed by minimizing the 2 on a grid of points (minimum 20*20) and iso-2 are constructed using interpolation. Each point (20 hours of computing) is calculated on a CE. A simple contour requires about 1 year of CPU on a single CPU. Thanks to datagrid (result in few days) To change: View -> Header and Footer

  11. The Zen program Minuit (ROOT library) Global Configuration file Fichier de Configuration CMB Fichier de Configuration BAO Zen.cc Configurator CMB code CMB 2 Minimizeur BAO code BAO 2 Minimum 2 and parameters To change: View -> Header and Footer

  12. Global configuration files Zen programs configuration Submit jobs on datagrid Submission graphical interface • A run is a set of n*n jobs (400) send in parallel. A graphical interface has been developed (thanks to Zuxuan Qian) to construct and submit them. To change: View -> Header and Footer

  13. Get jobs status Kill or submit jobs Get log and error files Manage output file Check output results and update jobs status Job control graphical interface • Jobs monitoring and output data manager To change: View -> Header and Footer

  14. Riess 2006: SNLS1+HST+new calib. Data Data CDM CDM ESR+Euchina: 10000 hours of CPU Diane Talon-Esmieu Cosmological constraint using BAO • First results using datagrid within: • ESR (Earth Science Research) VO (thanks to M. Petit-Didier) and Euchina Virtual organization • Using SN+CMB+BAO with frequentist statistic and (BAOfit from Sun Lei, PKU-CPPM Join PhD) ESR:40000 hours of CPU To change: View -> Header and Footer

  15. Summary and perspectives • The ZEN program is now running on datagrid Thanks to ESR virtual organization • The two graphical interfaces are very powerfull tools to submit jobs and to debug. • Major problem is still the linux version (SL3,SL4) • Our first results on multi-probes analysis are compatible with competitive analysis (Bayesian) • Perspectives: • Add new probes (WL) and wait for new data (PLANCK,SNLS3) • Investigate new theoretical models and implement them in ZEN • Add new statistics (MCMC, Bayesian…) • Optimize the speed • Start systematic analysis To change: View -> Header and Footer

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