{"knowledge_schema": {"broad_category": "Physics \u2192 Nuclear Physics \u2192 Many-Body Interactions", "refinement": "This problem focuses on the assumptions underlying the impulse approximation in nuclear interactions, particularly regarding nucleon behavior in a nucleus.", "specific_scope": "The task is to identify which assumptions collectively support the idea that nucleons behave like free particles during interactions, despite being part of a nucleus.", "goal": "Determine the correct set of assumptions that imply the impulse approximation in many-body nuclear calculations."}, "summary": "The problem involves understanding the impulse approximation in nuclear physics, which assumes that nucleons behave like free particles during interactions. To support this approximation, certain assumptions must hold true. The correct answer identifies the assumptions that imply this behavior, specifically that the interaction current only affects individual nucleons, the nucleus is transparent except for the selected nucleon, and that the selected nucleon experiences no binding forces. Thus, the answer is 1, 2, and 4."}