Light Charged Higgs Discovery Potential of CMS in the $H^{+-} \to \tau\nu_{\tau}$ with Single Lepton Trigger

In this note the CMS discovery potential for the light charged Higgs boson in the Minimal Supersymmetric Standard Model framework is presented. Different Higgs boson production mechanisms were studied to cover the mass range 125 < m(H+)< 170 GeV/c^2. The analysis is based on the CMS full simulation and reconstruction. Systematic uncertainties on the background determination are included. It is shown that the systematic uncertainities reduce the observability of H+ mainly at low tan(beta). Finally the 5 sigma discovery contour for an integrated luminosity of 30 fb^-1 is presented.