Study of J / ψ meson production inside jets in pp collisions at s = 8 TeV

摘要

A study of the production of promptJ/ψmesons contained in jets in proton-proton collisions ats=8TeVis presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb?1collected with the CMS detector at the LHC. For events with at least one observed jet, the angular separation between theJ/ψmeson and the jet is used to test whether theJ/ψmeson is part of the jet. The analysis shows that most promptJ/ψmesons having energy above 15 GeV and rapidity|y|<1are contained in jets with pseudorapidity|ηjet|<1. The differential distributions of the probability to have aJ/ψmeson contained in a jet as a function of jet energy for a fixedJ/ψenergy fraction are compared to a theoretical model using the fragmenting jet function approach. The data agree best with fragmenting jet function calculations that use a long-distance matrix element parameter set in which promptJ/ψmesons are predicted to be unpolarized. This technique demonstrates a new way to test predictions for promptJ/ψproduction using nonrelativistic quantum chromodynamics.