The effects of external fields on the neutral kaon system

The authors extended the field theoretical treatment developed by Sachs for the neutral kaon system to study the possible observable effects that external macroscopic fields may cause on this system. In particular, he used this treatment to study the interaction of the kaon system with the hypothetical hypercharge fields of various spatial configurations, and compared the theoretical predictions with the available experimental results. He recovered the results of ABCF 38 for the case of a spatially constant potential, and concluded that the most interesting parameters to study are the phase φ+- of the CP violation parameter η+-, and the charge asymmetry parameter δ. He also applied the formalism to study the effects of the interaction of the neutral kaon system with the hypothetical cosmological axion field, and concluded that the effects are too small to be observable. Furthermore, he illustrated the use of the formalism to give derivations of the regeneration formula