Mott scatter
The Mott scattering (according to Nevill F. Mott ) is the elastic scattering of a spin 1/2 particle ( fermion ) that is considered pointlike , e.g. B. an electron , on a static, pointlike charge without spin. It is used in nuclear and particle physics to examine the structures of nucleons ( protons and neutrons ) or their components, the quarks .
This scattering mechanism is similar to Rutherford scattering , in which a spinless particle is scattered on a charge. However, the magnetic moment associated with the spin results in an additional spinorbit interaction .
The elastic scattering of two pointlike particles that both have a spin is called Dirac scattering .
The differential cross section of the Mott scattering, the Mott cross section , is:
With
 : Ordinal numbers or charges (as multiples of the elementary charge) of the two particles involved
 e : elementary charge
 : electric field constant

E : relativistic total energy of the fermion after the scattering:
 p : momentum
 c : speed of light
 m : mass of the fermion

q : momentum transfer:
 Lorentz factor
 v : speed
 : Scattering angle .
The dependence on the scattering angle can be understood in such a way that the backward scattering ( ) is suppressed. This would correspond to a spin flip ; this is not possible with a spinless target particle .
In the nonrelativistic borderline case (i.e. neglecting the spin ), the Mott scattering cross section merges into the Rutherford scattering cross section.
The Mott scattering forms the basis for the Mott detector , with which the direction of the spin of electrons can be determined.