Ben R. Mottelson is an American physicist known for his significant contributions to the field of nuclear physics. Born on July 9, 1926, he was awarded the Nobel Prize in Physics in 1975, sharing it with Aage Bohr and Leo James Rainwater for their work on the structure of atomic nuclei. Mottelson's research has helped deepen the understanding of how protons and neutrons behave within the nucleus. Mottelson earned his Ph.D. from Harvard University and has held various academic positions throughout his career, including at Niels Bohr Institute in Denmark. His work has influenced both theoretical and experimental approaches in nuclear physics, making him a prominent figure in the scientific community.