The Upsilon meson is a type of subatomic particle known as a meson, which is made up of a quark and an antiquark. Specifically, the Upsilon meson consists of a bottom quark and its corresponding antiquark. It is part of the quark model in particle physics and is classified as a heavy meson due to its relatively large mass compared to other mesons. Discovered in 1977 at the Fermilab particle accelerator, the Upsilon meson plays a significant role in studying the strong force, which binds quarks together. Its properties help physicists understand the behavior of quantum chromodynamics, the theory that describes the interactions of quarks and gluons.