$ZZ o \ell^{+}\ell^{-}\ell^{\prime +}\ell^{\prime -}$ cross-section measurements and search for anomalous triple gauge couplings in 13 TeV $pp$ collisions with the ATLAS detector

摘要

Measurements of $ZZ$ production in the $\ell^{+}\ell^{-}\ell^{\prime+}\ell^{\prime -}$ channel in proton-proton collisions at 13 TeV center-of-massenergy at the Large Hadron Collider are presented. The data correspond to 36.1$\mathrm{fb}^{-1}$ of collisions collected by the ATLAS experiment in 2015 and2016. Here $\ell$ and $\ell'$ stand for electrons or muons. Integrated anddifferential $ZZ \to \ell^{+}\ell^{-}\ell^{\prime +}\ell^{\prime -}$ crosssections with $Z \to \ell^+\ell^-$ candidate masses in the range of 66 GeV to116 GeV are measured in a fiducial phase space corresponding to the detectoracceptance and corrected for detector effects. The differential cross sectionsare presented in bins of twenty observables, including several that describethe jet activity. The integrated cross section is also extrapolated to a totalphase space and to all Standard-Model decays of $Z$ bosons with mass between 66GeV and 116 GeV, resulting in a value of $17.3 \pm 0.9$ [$\pm 0.6$ (stat.) $\pm0.5$ (syst.) $\pm 0.6$ (lumi.)] pb. The measurements are found to be in goodagreement with the Standard-Model predictions. A search for neutral triplegauge couplings is performed using the transverse momentum distribution of theleading $Z$-boson candidate. No evidence for such couplings is found andexclusion limits are set on their parameters.