Based on Phys.Rev.D83:074023,2011 (arXiv:1012.1207) by Yanou Cui, Zhenyu Han and Matthew D. Schwartz.
If you just want the code, here is the C++ implementation of our W-tagger.
Efficient W-tagging can save signals from background
Before W-tagging -- new physisc (Z') is lost in background
After W-tagging -- new physics (Z') is clearly visible with high significance
How do we identify highly-boosted hadronically-deacying W bosons?
The key is a multivariate approach using jet substructure. We use the following 7 variables
- Jet mass with R=0.5 Cambridge/Aachen Jets
- Jet mass with R=0.4 Cambridge/Aachen Jets
- Filtered Jet mass
- Mass of hardest subjet, from filtering
- Mass of second hardest subjet, from filtering
- ratioof the pT's of the two hardest subjets
- Planar Flow
The variables are combined using Boosted Decision Trees. The result can increase S/sqrt(B) by larger than a factor a 5, as compared to preious approaches (filtering + mass drop) which acheived slightly larger than a factor of 2, as shown in this figure
The C++ CODE impliementating the W-tagging algorithm can be found here.