Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Ran Huo Applicant's institution: ANL Applicant's division: HEP Project Name: DDM Project title: Decaying Dark Matter Associated funding: Research Assistent from uchicago Other Systems: At bangcompute.uchicago.edu, tested for 1k CPUh Science: We have evidence that the universe consists of Dark Matter (DM), but we don't know the property of DM as particle. One issue is whether the DM particle is stable, or it has undergone decay. Given that the two product particles are collisionless, if the DM decays at the medium stage of the universe evolution, namely, just around Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) formation, current observation can set stringent bound on its property. Basically the decay will introduce free streaming which suppress the small scale structure on LSS, and introduce relativisitc component which lifts the acoustic peaks on CMB. Compared with the literature, our analysis will be comprehensive and the first to set numerical bound on mass ratio between the parent particle and the product particles. Project description: We run the modified public code "cosmomc", which is a Markov Chain Monte Carlo engine for exploring cosmological parameter space. It calls modified lib "camb" to compute theoretical spectrum for parameters, and analysize with data from WMAP and other observation to finally determine a parameter likelihood distribution. The code has internal scaling, and since it is parallel, the scaling is arbitrary. The public library used are LAPACK -- Linear Algebra PACKage, CFITSIO - A FITS File Subroutine Library, MKL - Intel Math Kernel Library. A test on a small cluster for 2 days is completed and it ran for 3000 parameters. The test is partially MPI, which is, the theoretical "camb" part is MPI, and not the data analysis. With the full power of LCRC, hopefully several days work will give enough parameter points, which would be order 100k. Now only one member is expected. Project URL: Requested allocation: 280000 Justification: The requester has used 0 hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System