Can I present new arguments in the conclusion of my research paper?
No, it’s not appropriate to present new arguments or evidence in the conclusion. While you might be tempted to save a striking argument for last, research papers follow a more formal structure than this.
All your findings and arguments should be presented in the body of the text (more specifically in the results and discussion sections if you are following a scientific structure). The conclusion is meant to summarize and reflect on the evidence and arguments you have already presented, not introduce new ones.