PowhegControl: width_correction keyword for bb4l-beta
Correct the powheg keyword widthCorrection to width_correction. This Powheg keyword is only used in the bb4l beta version (bb4l-dl and bb4l-sl).
Correct the powheg keyword widthCorrection to width_correction. This Powheg keyword is only used in the bb4l beta version (bb4l-dl and bb4l-sl).