Absolute determination of D_s branching ratios and f_{D_s} extraction at a neutrino factory

Abstract

A method for a direct measurement of the exclusive D_s branching ratios and of the decay constant f_{D_s} with a systematical error better than 5% is presented. The approach is based on the peculiar vertex topology of the anti-neutrino induced diffractive charm events. The statistical accuracy achievable with a neutrino factory is estimated.