Open charm reconstruction in ALICE: ${\rm D^+\to K^-\pi^+\pi^+}$

Open charm mesons produced in high energy A-A interactions are expected to be powerful probes to investigate the medium produced in the collision. In this context it is important to measure the production of as many charmed hadrons as possible, such as D$^0$, D$^+$, D$^+_s$ and $\Lambda_c$, because the measurement of their relative yield can provide information on the hadronization mechanism and is necessary to reduce the systematic error on the absolute cross section. The ALICE experiment at the LHC is designed to perform such measurements at midrapidity down to $p_T$ below 1 GeV/c, mainly by means of the silicon vertex and tracker detector, the time projection chamber and the time of flight detector. One of the main channels for the detection of charm production in ALICE is the exclusive reconstruction of the D$^+$ meson through its three charged body decay $K^-\pi^+\pi^+$ in Pb-Pb ($\sqrt s=5.5$ TeV) and pp ($\sqrt s=14$ TeV) collisions. The selection strategies for this analysis and the results of a feasibility study on Monte Carlo events will be presented together with the perspectives for the study of D$^+$ quenching and azimuthal anisotropy measurements.