LHC dijet angular distributions as a probe for the dimension-six triple gluon vertex

Abstract

In the absence of a concrete discovery of new physics at the LHC, global analyses of the standard model effective field theory (SMEFT) are important to find and describe the impact of new physics beyond the energy reach of the LHC. Among the SMEFT operators that can be constrained via various measurements, the dimension six triple gluon operator involves neither the Higgs boson nor the top quark, yet its variation can have measurable effects on top and Higgs production. Without independent constraints on its impact, the sensitivity of measurements in the top and Higgs sectors to new physics is reduced. Previous analyses have used various techniques to constrain the influence of the triple gluon operator. We show that the dijet angular distribution is a powerful observable for probing the triple gluon operator because of the different helicity structure of the dimension-six interaction, namely the lack of a t-channel exchange term, as compared with expectations from QCD. Using this novel approach, we set the most stringent limit on the size of the triple gluon effective coupling by reinterpreting the results of a search for new phenomena in dijet events using 35.9 fb−1 of pp collision data collected at s=13 TeV performed by the CMS Collaboration.