Beam Polarization and Cross Section

Sleptons have handedness though they are scalar particles. Because of this their productions cross sections depend on the electron beam polarization. You can thus select the slepton handedness by adjusting the beam polarization.
The following java applet shows you how the cross sections for smuon pair production depend on the beam polarization. You can change the beam polarization by dragging your mouse left or right in the graph window. The blue curve is the right-handed slepton (smu_R), while the red one is the left-handed slepton (smu_L).