It may not be the best place to ask but that is the best place I found :)

So I have been trying to calculate kinematic variables for the following process (incoming electron with energy ~360MeV and neutron at rest) :

[tex]e^- + n \rightarrow e^- + \Delta^0 \rightarrow e^- + \pi^- + p [/tex]

So I tried to find the final pion energy, [tex]E_\pi[/tex] as a function of it's solid angle ([tex]\theta_\pi[/tex],[tex]\phi_\pi[/tex]),the electron initial and final 4-momenta as well as [tex]Q^2[/tex] and the various masses...

The problem is that I found 2 solutions for [tex]E_\pi[/tex] as I end up with a second order polynomial and both solutions seems physical to me... is it normal or I have been doing something wrong? I can post some detailed calculations if needed.