Hadron structure is a research area in particle physics that focuses on studying the internal structure of hadrons, which are composite subatomic particles made up of quarks and gluons. Researchers are interested in understanding the distribution of quarks and gluons within hadrons, as well as their interactions and dynamics. This field of study involves experimental techniques such as deep inelastic scattering, as well as theoretical approaches such as quantum chromodynamics (QCD) and lattice QCD calculations. By studying hadron structure, scientists aim to gain insights into the fundamental forces and particles that make up the universe.