Measurement of the ZZ production cross section and anomalous trilinear gauge couplings in lll'l' decays at sqrt(s) = 8 TeV at the LHC

Measurements are presented of the ZZ production cross sections and anomalous triple gauge couplings in proton-proton collisions at $\sqrt{s} = 8~\rm{TeVa}$ with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of 19.6 fb$^{-1}$. The measurements are performed in the leptonic decay modes $\rm{ZZ} \rightarrow \ell\ell\ell'\ell'$, where $\ell$ = e, $\mu$ and $\ell'$ = e, $\mu$, $\tau$. The measured cross section $\sigma ( \rm{pp} \to \rm{ZZ}) = 7.7^{+0.5}_{-0.5} ~(\rm{stat}) ^{+0.5} _{-0.4}~(\rm{syst}) \pm 0.4~ (\rm{theo)} \pm 0.3~(\rm{lum})~\rm{pb}$ for both Z bosons produced in the mass region $60 < m_{\rm{Z}} < 120~\rm{GeV}$, is consistent with standard model predictions. Differential cross sections are measured and well described by the theoretical predictions. A limit extraction on anomalous ZZZ and ZZ$\gamma$ couplings is based on the invariant mass distribution of the four-lepton system. The measured couplings: $-0.004<f_4^Z<0.004$, and $-0.005<f_5^Z<0.005$, and $-0.004<f_4^{\gamma}<0.004$, and $-0.005<f_5^{\gamma}<0.005$ at 95\% CL, are in good agreement with the standard model predictions.