Study of the tracking efficiency of charged pions at BESIII

Using (10087 \pm 44) \times 10^6 J/\psi events collected with the BESIII detector in 2009, 2012, 2018 and 2019, the tracking efficiency of charged pions is studied using the decay J/\psi \rightarrow \pi ^+ \pi ^- \pi ^0 . The systematic uncertainty of the tracking efficiency and the corresponding correction factors for charged pions are evaluated, in bins of transverse momentum and polar angle of the charged pions.