dkfiles for Lc_XiKpi Xic_XiKpi Xic_XiKpi with AmpGen and tight generator level cuts
Add dkfiles/Lc_XiKpi=AMPGEN,TightCut.dec dkfiles/Xic_XiKpi=AMPGEN,TightCut.dec dkfiles/Xic_Xipipi=AMPGEN,TightCut.dec.
Related Gauss MR: lhcb/Gauss!640 (merged)
WG presentation with production request: https://indico.cern.ch/event/869343/#2-first-observation-of-xi_c-to