{"knowledge_schema": {"broad_category": "Physics \u2192 Relativity \u2192 Particle Physics", "refinement": "This problem involves the collision of particles (proton and antiproton) and the resulting annihilation that produces photons, focusing on energy conservation and momentum conservation in relativistic contexts.", "specific_scope": "The scenario describes a specific case of particle annihilation where both particles have the same Lorentz factor, leading to the production of two photons with equal energy and specific directional properties.", "goal": "Determine the angle between the directions of the two photons produced from the annihilation of the proton and antiproton."}, "summary": "This problem is rooted in the principles of relativistic particle physics, specifically focusing on the annihilation of a proton and an antiproton. Both particles have the same Lorentz factor, indicating they have equal relativistic speeds but in opposite directions. Upon annihilation, they produce two photons with equal energy, moving in different directions. The task is to calculate the angle between the two photon directions, which is determined to be 120 degrees based on conservation laws and the geometry of their trajectories."}