{"knowledge_schema": {"broad_category": "Physics \u2192 Particle Physics \u2192 Nuclear Decay", "refinement": "This problem examines the energy spectrum of particles resulting from nuclear decay processes, specifically focusing on the emission of lighter particles and the effects of changing decay products.", "specific_scope": "The focus is on comparing the energy spectrum of outgoing particles in two different decay scenarios: one with two light particles and one with one massless particle.", "goal": "Determine how the change in decay products affects the energy spectrum of the emitted particles."}, "summary": "In this problem, we analyze the energy spectrum of outgoing particles from a nuclear decay process. The original decay emits two light particles, resulting in a continuous energy spectrum with a certain endpoint. When one of the decay products is replaced with a massless particle, the energy spectrum remains continuous but adjusts in shape, and the endpoint increases due to the additional energy contribution from the massless particle. Thus, the correct answer is that the spectrum remains continuous with an adjusted shape, and the endpoint increases."}