Question

Ejercicio 1 a) Show that the Bjorken variable z/2Mv is a Lorentz invariant and that it can by the quark Hint: Use the reference frame in which the proton is moving with a very high velocity, so that the transverse momenta and rest masses of its constituents may be neglected.

Answer 1

Bjorken Variable:

$x= \frac{-q^2}{2M\nu}$

q: charge(doesn't change with Lorentz transformation)(i.e. q'=q)

M: mass

dM C2

$\nu$: frequency

$\nu'= \nu*\sqrt{1-\frac{v^2}{c^2}}$

Now Lorentz transformation of x

12

2*

x'=x (Lorentz invariant)