Triangle Nuclear Theory Colloquium - Pion Mass Dependence in Chiral EFT and the QCD Axion

Presenter: Mia Kumamoto

QCD and effective field theory together put low energy nuclear physics on solid theoretical footing to calculate observables with some confidence, but open questions remain. Two related questions are why QCD seems not to violate CP and how the properties of nuclear matter depend on the light quark masses (or equivalently the pion mass). The classic solution to the former problem is to invoke a new light field, the QCD axion, a well-motivated dark matter candidate which a diverse experimental campaign is currently searching for. Neutron stars can also probe the QCD axion parameter space if nuclear matter becomes more attractive at reduced pion mass via the formation of an axion condensate. Answering the question of whether an axion with a mass at the QCD prediction could condense in neutron stars hinges on a number of fundamental questions in nuclear physics, including the properties of three nucleon forces, the importance of light resonances neglected in chiral EFT, fine tuning in s-wave scattering, and at what density chiral symmetry restoration occurs in cold nuclear matter. In this talk, I will present our current research on pion mass dependence in chiral EFT, possible observable signatures in neutron stars, and what the study of pion mass dependence can teach us about extant theoretical problems in low energy nuclear physics.

Contact

Steffen Bass
bass@duke.edu