We discuss the foundation of the Trojan Horse Method (THM) within the Inclusive Non-Elastic Breakup (INEB) theory. We demonstrate that the direct part of the INEB cross section, which is of two-step character, becomes, in the DWBA limit of the three-body theory with appropriate approximations and redefinitions, similar in structure to the one-step THM cross section. We also discuss the connection of the THM to the Surrogate Method (SM), which is a genuine two-step process.
Bertulani, C. A., Hussein, M. S., & Typel, S. (2018). Assessing the foundation of the Trojan Horse Method. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 776, 217–221. https://doi.org/10.1016/j.physletb.2017.11.050