Isobar Collisions at RHIC to Test Local Parity Violation in Strong Interactions

The discovery of the Higgs boson has completed the Standard Model of fundamental interactions. The Standard Model describes the strong and electroweak interactions by generalizing the concept of local gauge invariance that underlies the Maxwell theory of electromagnetism to non-Abelian gauge groups. A non-Abelian group has the elements that do not commute, such as the group of rotations in three dimensions, where a rotation around axis x followed by a rotation around axis γ yields a different result from doing these rotations the other way around. The resulting theory is both elegant and powerful—it is believed to describe all known properties of the physical world, except gravity. In spite of their deceptively simple structure, non-Abelian gauge theories possess many surprising features that are still not understood.