DESI Mock Challenge: Preparing DESI Pipeline for LSS analysis*

 In this talk I will describe the DESI Mock Challenge.  DESI is a multi-object spectrograph currently collecting the largest data set of galaxy/quasar spectrum ever assembled. It is expected to provide the most precise measurement of dark energy. To achieve this, it is paramount that the accuracy of the data analysis pipeline is robust(i.e. systematics error is less than the statistical error) compared with previous stage III experiments. That is why we need to thoroughly validate all the pieces of the pipeline. The goal of the Mock Challenge is to build the analysis pipeline to extract cosmological information from the large-scale structure of galaxy clustering.  We study the accuracy and  precision of the main observables for DESI. We compare and cross-validate codes from different groups to build the pipeline and use state-of-art simulations to validate them. The mock challenge covers three main challenges: 1) Covariances 2) BAO and Reconstruction and 3) RSD and Full Shape Analysis . I will present briefly the methodology, the goals, the preliminary results and the near future plans.