In high energy particle physics nucleon-lepton scattering, the semi-inclusive deep inelastic scattering (SIDIS) is a method to obtain information on the nucleon structure.
[1] It expands the traditional method of deep inelastic scattering (DIS).
In DIS, only the scattered lepton is detected while the remnants of the shattered nucleon are ignored (inclusive experiment).
Likewise, by detecting the leading hadron, one essentially tags (i.e. identifies) the quark on which the scattering occurred.
SIDIS will be an important technique used in the future Electron Ion Collider scientific program.