1 Unfolding Study Closure test on SHERPA 08/10/12

2 RooUnfold Using the RooUnfold In this study we make response matrix from MADGRAPH MC and use it to unfold the SHERPA sample Plots we are interested are rapidity of Z and jet in Z+1jet events i.e. Yz, Yjet, different of Yz and Yjet, and sum of Yz and Yjet The unfolding methods are  Bayes with number of iteration = 4  Svd with ktern =15 (total number of bins) i.e. just inverts matrix  Bin by Bin

3 Response Matrix MADGRAPH

4 |Y of Z| BayesSvdBin by Bin The corrections for all 3 methods are small. The corrections are almost the same for all 3 methods.

5 |Y of jet| BayesSvdBin by Bin The corrections are small. The corrections are almost the same for all 3 methods.

6 0.5|Y z +Y jet | BayesSvdBin by Bin Y sum again shows the small and consistent corrections for all methods (except the last bin).

7 0.5|Y z -Y jet | BayesSvdBin by Bin Y diff shows the small corrections but not the bin before last..

8 Keng's Comments 1. By using MADGRAPH response matrix, the corrections for SHERPA are small and consistent. 2. The correction also look the same for all methods. 3. The bin before the last of Ydiif show big corrections. We saw the same effect in PYTHIA