Title: Nucleon electric dipole moments from Lattice QCD
Speaker: Sergey Syritsyn. Stony Brook
Abstract: Experimental observation of nucleon electric dipole moments (nEDMs) would be evidence of nonzero QCD theta-term or CP violating (CPv) interactions beyond the Standard model. CP violation is a prerequisite for baryogenesis and is necessary for explaining the baryon asymmetry of the Universe. Experimental bounds on nEDMs can constrain the QCD theta term and effective quark-gluon CP-violating interactions. Taken together with the observed amount of nuclear matter, they can help select and constrain viable extensions of the Standard model.
In order to relate experimental bounds on nEDMs to limits on quark-gluon CPv interactions, theoretical nucleon structure calculations are necessary. Nonperturbative QCD calculations on a lattice have reached a respectable level of statistical and systematic precision for hadron spectrum and many nucleon structure observables such as the axial charge and form factors. However, producing correct and reliable results for nucleon EDMs on a lattice has proved numerically (and theoretically) challenging. In this talk, I will overview the current status and recent results of lattice calculations of nEDMs induced by the QCD theta term and by the lowest-dimension quark-gluon CPv interactions. Lattice QCD is poised to yield model-independent connection between nEDMs and quark-gluon CPv interactions, and I will discuss the outlook for computing these quantities with physical quark masses.