New COMPASS results on $\Delta G/G$ using $D^{0}$ production asymmetries

One of the main goals of the COMPASS experiment is the measurement of the gluon contribution to the nucleon spin. Among the processes studied by COMPASS, the Open-Charm $D^{0}$ meson production is the cleanest channel for the gluon polarisation estimation. The experimental spin asymmetry for these open-charm events was measured after an efficient removal of the combinatorial background using a method based on a Neural Network approach. The gluon polarisation was then estimated through the relation between this asymmetry and the analysing power (asymmetry at the partonic level) for the polarised "photon-gluon fusion" process, in a LO QCD approximation. A new D0 decay mode was considered ($D^{0} \rightarrow K \pi\pi\pi$ ), together with a first analysis of the COMPASS proton data ($NH_{3}$ target), producing a new result with an improved precision. This value includes all COMPASS data and it is shown here for the first time.