We report a measurement of the fraction of top quark pair events produced via gluon-gluon fusion in $p\bar{ p}$ collisions at $\sqrt{ s} = 1.96 ~\rm TeV$ in lepton+jets final states using the full RunII data set corresponding to $9.7 ~\rm fb^{ -1}$ of integrated luminosity collected by the D\O\ experiment. We utilize a boosted decision tree to distinguish top quark pair events produced by $q\bar{ q}$ annihilation and $gg$ fusion. We perform a template fit to extract the $t\bar{ t}$ production fraction via $gg$ fusion and find $f_{ gg} = 0.096 \pm 0.039 ~(\rm stat.) ~^{ +0.077}_{ -0.062} ~(\rm syst.)$.
Categories: hep-ex