Does anyone know how you find the length of the energy-momentum four-vector for a system of particles?(adsbygoogle = window.adsbygoogle || []).push({});

p_mu=(E/c,p)

where length is:

length(p_mu)=-(E/c)^2+(p)^2

Do you first add the corresponding vector elements then find the length

OR

find the length of each particle first then sum the individual lengths.

Cheers,

Jimmy

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# Energy-momentum Four-vectors

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