Recent content by Scott75

Yes that is what I meant but couldn't get off that train of thought as misunderstood the meaning of 'randomly oriented'. I could see it working if the primary particles had the same speed, all secondary particles had equal masses and their velocities all made an equal angle to their primary...

If only they had written the word 'beam'!

I understood all of that before posting the original question. So perhaps I have misunderstood the setup. I could see how it worked nicely with a beam but ruled it out as took 'randomly oriented' primary particles to mean they travel in random directions. On page 1 he describes a particles as a...

Completey agree but isn't that for the C system applied to one primary particle that is at rest? For more than one particle I thought the C system is where the total momentum is zero. So why can't the resulting particles of a given kind have different energies as their speeds don't have to be...

Yes of a given kind. I would say given kind implies the same mass and internal energy. Agreed the same process happens but the direction of the the resulting particles is random as long as conservation of momentum and energy are satisfied. Hence the circle with radius equal to the velocity of...

What are those symmetry conditions? I can think of symmetry conditions where the resulting particles (of a given kind) have different energies but satisfy conservation of energy and momemtum

He also says they all have the same energy when viewed from the C system which is what I'm struggling with.

Agree with your last point. All that can be said is a primary particle spontaneously decays into two.

I don't think it's possible to define the orientation that way. When considering only one primary particle there is not enough information to determine the direction of the resulting particles. All that can be said from the C system is the resulting particles travel in opposite directions with...

Can it be a beam of primary particles if they are randomly oriented? I assumed randomly oriented meant the primary particles are traveling in random directions.

Thanks for the reply. But this means V in eqn 16.8 isn't constant. I'm beginning to think the wording and equations suggest that a C system is where the total momentum of the whole system is zero and, due to the primary particles being isotropically distributed, the K.E. of resulting particles...

On page 41 for the spontaneous disintegration of a particle into two, Landau states the total momentum in the C system is zero. On page 43 for the disintegration of many particles into two, Landau states: In the C system... every resulting particle (of a given kind) has the same energy... I...