The HERMES experiment
The HERMES experiment collected data from scattering of longitudinally polarised electrons on various polarised gas targets such as hydrogen, deuterium, or helium. The main goal of the HERMES experiment is to map out the spin structure of the nucleon, i.e. protons and neutrons. These nucleons are made up of quarks with spin-1/2, bound together by gluons with spin-1. The HERMES experiment is trying to answer how the constituents make up a nucleon, which has spin-1/2. The Collaboration continues to publish results delving deeper into the spin structure of the building blocks of matter.