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Shiz
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Homework Statement
So a kaon moving at some speed in the +x direction spontaneously decays into one pion and one anti-pion. The anti-pion moves away with velocity of 0.8c, and the pion moves away with velocity of 0.9c.
Mass of kaon = 498 MeV/c^2
Mass of pion/anti-pion = 140 MeV/c^2
Homework Equations
I understand that momentum of the kaon qualms the momentums of the two pions. p(kaon) = p(pion) + p(anti-pion). I can then square both sides and use the principle of invariance.
The Attempt at a Solution
What I'm having issues with is how to calculate the term of +2 p(pion)•p(anti-pion).
I don't understand how to multiply the vector parts. p(pion) = ( E(pion)/c , vector p(pion) )
p(anti-pion) = ( E(anti-pion)/c , vector p(anti-pion) )
I'll get a cos(theta) term out of this dot product on the vector side but how do I use the velocities I have to get a dot product of those two momentum vectors? They're both moving so I am guessing I have to substitute in (gamma)(mass of the particle)(velocity vector) but I just don't understand how to do the math after that.
Help please!