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Re: vector quantities and energy



Hi all,
As for this, we all know that momentum is a vector and energy is
a scalar. Even in the 4-D momentum to calculate the disintegration that
Paolo describes, it is most easily done this way. However, the energy
occupies the "scalar part" of the vector.
Something more interesting though, is that high energy
physicists do treat energy as a vector. We have transverse and
zero-degree energy. These are based on the fact that we can not put
particle detectors inside the beam pipe to measure the energy in every
direction. So we concentrate on the stuff transverse to the beam in
collider experiments. But those experiments that only have one beam
meeting a target foil (fixed target experiments) can measure the
zero-degree enegry in the beam dump (or stop) by making it a
calorimeter. Look back at the initial report of the discovery of the
top quark by CDF in Spring 1994. Look closely at their definitions of
event selection especially with their vertex detector (one that is as
close to the collision as possible). They look for missing stuff and
energy in certain directions. Hmmm??
We must really love messing things up. Oh well.


Regards,
Sam Held