Studies of d E /d x measurements with the BESIII

The Beijing Spectrometer III (BESIII) is a general-purpose detector used for the study of τ-charm physics at the Beijing Electron-Positron Collider II (BEPCII). This paper presents our studies of the d E /d x measurement in the drift chamber of BESIII, which is important for the identification of charged particles. Corrections applied to the d E /d x measurement in data reconstruction are discussed. After our current d E /d x calibration, a resolution of about 6% has been obtained for minimum ionization particles, and a 3σ K/π separation is obtained for momenta up to 760 MeV/ c . These results meet the design goals of the BESIII drift chamber.