Searches for New Physics

Abstract

While the Standard Model (SM) of particle physics has been very successful in describing as well as predicting numerous phenomena, it provides no insight into the nature of dark matter and dark energy. Moreover, SM is not consistent with the present observable Universe, which has a glaring imbalance of matter and antimatter. Despite decades of effort, all attempts to unify gravity with other fundamental interactions remain unsuccessful. The advances in atomic, molecular, and optical (AMO) precision measurementsprecision measurement, coupled with improved theoretical description, enabled new tests of fundamental physics. Revolutionary developments led to the extraordinary precision now reached by atomic clocks, other spectroscopy measurements, atomic magnetometers, laser and atom interferometers, and other precision AMO experiments. These advances bring forth a question: Do our current laws of fundamental physics hold at the level of experimental precision? Modern physics is based on a number of cornerstone principles such as Lorentz invariance, universality of free fall, local position invariance, constancy of fundamental constants, etc. However, in many theories beyond the Standard Model (BSM), these principles no longer hold, and discovery of their violation will be a first glimpse into the nature of BSM physics. AMO studies aimed to search for new physics beyond SM and to test the fundamental physics postulates are the subject of this chapter. This entire topic was recently reviewed in detail in 1. In this chapter, we briefly discuss AMO studies in parity nonconservation, time-reversal violation including electric dipole moments, tests of the CPT theorem, tests of general relativity, and the search of the violation of local Lorentz invariance. The tests of quantum electrodynamics (QED), constraints on variations of fundamental constants, and searches for new particles, including dark matter, are discussed in other chapters.