Implications of an R-Scan for Charm Physics

Abstract

The impact of improved measurements of the cross section for electron-positron annihilation into hadrons in the charm threshold region is discussed. Two aspects are studied in detail: i.) A significant reduction of the experimental error of the electronic width of the narrow resonances J/ψ and ψ and of the continuum cross section from the open charm threshold up to 4.6 GeV will lead to a correspondingly improved determination of the charmed quark mass; ii) A high luminosity measurement with 24 pb −1 at three points and with a spacing of 2 MeV around √ s = 3511 MeV may allow to observe the direct, resonant production of χ c1 .