The smallest possible model that combines the standard model of elementary particle theory with supersymmetry. It predicts that all the fermions and gauge bosons of the standard model should have supersymmetric partners and that there should be five Higgs bosons. The fact that no supersymmetric particles have been found at the Large Hadron Collider suggests to many physicists that the MSSM is not correct, and that if supersymmetry is a symmetry of nature then it will be realized in a more complicated theory, such as a supersymmetric version of the standard model combined with a family symmetry.