# Exercise 9: A bit more physics (15 minutes)

Assuming a relativistic particle, the measured energy of the particle in our example n-tuple is given by

$E_{meas}^{2} = p_{x}^{2} + p_{y}^{2} + p_{z}^{2}$

and the energy lost by the particle is given by

$E_{loss} = E_{beam} - E_{meas}$

Create a new analysis macro (or revise one of the ones you’ve got) to make a scatterplot of $$E_{loss}$$ vs. zv. Is there a relationship between the z-distance traveled in the target and the amount of energy lost?