Implementation of Charge Exchange Processes in Geant4

We implement charge exchange processes in Geant4 and introduce a new G4ChargeExchangeXS class. We also update the G4ChargeExchange and G4ChargeExchangePhysics classes in Geant4. It is found that the parame- terized experimental cross-section curve of π0 production in charge exchange process π− + p → $π^{0}$ + n aligns with the Bertini Cascade Model data and SAID data. We then extend this approach to calculate the eta and neutral kaons production in the corresponding charge exchange processes. We also introduce a new fitting formula to describe the charge exchange processes in nuclei. We expect our work will be useful in studying calorimeter reports in LHC experiments and simulating the background in the NA64 experiment at CERN.