Strangeness-Conserving Hadronic Weak Interaction -- The Weakest Link in Testing the Standard Electroweak Model?
Although the Glashow-Weinberg-Salam theory is believed to be correct in describing the unified electroweak interaction, the tests of it in the strangeness-conserving hadronic sector are still not as successful as in other sectors. The major challenge, both theoretically and experimentally, comes from the fact that these tests can only be performed in nucleon-nucleon systems, where the strong interaction is omnipresent.In this talk, the history and current status of this field, and also its importance in elucidating the hadronic weak neutral current and dynamics not accessible by strong-interaction probes, will be briefly reviewed. The focus will be on the parity-violating nucleon-nucleon interaction, which is to be determined/constrained by experiments and compared with hadronic predictions based on the underlying theory. The recent re-formulation of this interaction in terms of effective field theory and future exploratory directions will be discussed.