ZZ cross section measurement at 8TeV

We present a measurement of ZZ production in the $l^{+}l^{-}l^{prime+}l^{prime-}$ channel with $pp$ collisions at $sqrt s = 8 ~TeV~$ using data corresponding to an integrated luminosity of 20 $fb^{-1}$ collected by the ATLAS experiment in 2012. The fiducial cross section is measured to be $20.73^{+1.32}_{-1.19}(stat)^{+0.81}_{-0.81}(syst)^{+0.60}_{-0.56}(lumi)$ fb. The total cross section is measured to be $7.10^{+0.46}_{-0.41}(stat)^{+0.29}_{-0.29}(syst)^{+0.21}_{-0.19}(lumi)$ pb, which is consistent with the Standard Model expectation of $7.23^{+0.30}_{-0.22}$ pb.