In particle physics, quenched approximation is an approximation often used in lattice gauge theory in which the quantum loops of fermions in Feynman diagrams are neglected. Equivalently, the corresponding one-loop determinants are set to one. This approximation is often forced upon the physicists because the calculation with the Grassmann numbers becomes relatively awkward in lattice gauge theory. Particles erupt from the collision point of two relativistic (100GeV) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... It has been suggested that this article or section be merged into Lattice field theory. ... Fermions, named after Enrico Fermi, are particles which form totally-antisymmetric composite quantum states. ... In this Feynman diagram, electrons annihilate and become a quark-antiquark pair. ... In mathematics, the exterior algebra (also known as the Grassmann algebra) of a given vector space V is a certain unital associative algebra which contains V as a subspace. ...

Most of the recent calculations avoid the quenched approximation.