WW production cross section at 13 TeV

Precise measurement of $W^{+}W^{-}$ production process empowers our understanding of Standard Model and also probes new physics phenomena at higher energies. This talk presents the total and fiducial cross section measurement of $W^{+}W^{-}$ process at a centre-of-energy $\sqrt{s}$ = 13 TeV with the data collected by the ATLAS detector in 2015. The events are selected in the leptonic decay channel i.e both W decaying into two leptons (electrons, muons) and associated missing transverse momentum.