Measurements of the production of vector bosons in association with heavy flavour quarks at ATLAS.

The production of heavy flavour quarks in association with a vector boson represents an important process to study quantum chromodynamics. High precision is achieved in measurements of differential cross sections and comparisons are made to state-of-the-art next-to-leading-order quantum chromodynamics calculations and different parton distribution function parameterizations. The measurement of the production of a $W$ boson in association with $b$ quarks or with a single charm quark using 4.6 fb$^{-1}$ of pp collisions at $\sqrt{s}$ = 7 TeV with the ATLAS detector is reported. The $W+c$ measurement is performed for events with a $W$ boson plus a tagged $c$-jet or a $D/D^*$ meson. $W+c$ cross sections integrated over a fiducial kinematic range with their impact on the $s$-quark density in the proton are reported.