Yes, I believe that is a good way to analyze the system. We, as observers, should not have much to say about what happens between two individual particles. The action should be determined by the relative motion and position of the two bodies. That would be defined by their center of mass. So when we hear mention of ultra low energy neutrons being capable of special interactions then we should look at the other side of the process. If the other interacting body is relatively hot, then that will dominate.
One thing to consider. The mass of the neutron is much less than the mass of the nickel nucleus so the center of mass observation frame would be moving at a velocity that is closer to that of the nucleus velocity. Dave -----Original Message----- From: Eric Walker <[email protected]> To: vortex-l <[email protected]> Sent: Tue, Mar 26, 2013 9:47 pm Subject: Re: [Vo]: Low Energy Neutrons and Local Temperature On Tue, Mar 26, 2013 at 9:15 AM, David Roberson <[email protected]> wrote: I was considering the behavior of ultra low momentum neutrons within a metallic structure and a question arose. Why would the local temperature of the nickel atoms not completely dominate the activity of the low momentum neutrons? I think this is an interesting line of reasoning. I recall reading that it is the center of mass system that is important for reactions. Take a (hypothetical) near-stationary neutron and an energetic nickel lattice atom. I believe their interaction is characterized by the center-of-mass system that takes them both into account -- if the nickel atom is moving quickly towards the neutron, according to the center-of-mass system they are moving towards one another at equal velocities. Eric
