Session BC: Plenary II

Present Status and Future Prospects of EDM Measurements

Searches for a permanent electric dipole moment (EDM) began in 1951 with the neutron. Up to the present, many systems, including nuclei, atoms and molecules, have been explored and no evidence for an EDM has been found. The search for the EDM is currently driven by the desire to explain the over-abundance of matter relative to anti-matter in the universe. The dynamical origin of this imbalance, or baryogenesis, is thought to have occurred a few picoseconds after the Big Bang, driven by combined Charge Conjugation-Parity (CP) symmetry violating processes beyond those predicted by the Standard Model (SM) of particle physics. The same CP-violating process at high energies would generate EDM signals many orders of magnitude above the SM prediction. In many scenarios, successful baryogenesis leads to strict lower bounds on the nEDM on the order of our target sensitivity of $3\times 10^{-27}$ e-cm. In this talk, I will review the history of EDM measurements and describe the present experimental techniques and physics reaches.   

Short-Range Correlations And The Quarks Within

Short-range correlations (SRC) are pairs of strongly interacting nucleons at close proximity. Due to their large spatial overlap and high relative-momentum, the study of SRC pairs is an appealing gateway for probing the strong nuclear interaction at high-densities (i.e. short-distances) and its relation to the underlaying quark-gluon substructure of nuclei. In this talk I will present new results from high-energy electron scattering experiments that probe SRC pairs via measurements of exclusive hard breakup reactions. Special emphasis will be given to the effect of SRCs on the behavior of protons in neutron-rich nuclear systems and how it can impact properties of dense nuclear systems such as neutron stars. Pursuing a more fundamental understanding of short-distance interactions, I will present new measurements of the internal quark-gluon sub-structure of nucleons and show how its modification in the nuclear medium relates to SRC pairs and short-ranged nuclear interactions. Last, I will also discuss the development of new effective theories for describing short-ranged correlations, the way in which they relate to experimental observables, and the emerging universality of short-distance and high-momentum physics in nuclear systems.