J_E_T : a global jet finding algorithm

We introduce a new jet-finding algorithm for a hadron collider based on maximizing a J_E_T function for all possible combinations of particles in an event. This function prefers a larger value of the jet transverse energy and a smaller value of the jet mass. The jet shape is proved to be a circular cone in Cartesian coordinates with the geometric center shifted from the jet momentum toward the central region. The jet cone size shrinks for a more forward jet. We have implemented our J_E_T algorithm with a reasonable running time scaling as Nn 3 , where “ N ” is the total number of particles and “ n ” (≪ N ) is the number of particles in a fiducial region. Many features of our J_E_T jets are similar to anti- k t jets, including the reconstructed jet momentum and the “back-reaction” from soft contamination. Nevertheless, when the jet parameters in the two algorithms are matched using QCD jets, we find that the J_E_T algorithm has a larger efficiency than anti- k t for identifying objects with hard splittings such as a W -jet.