Search for Physics beyond Standard Model at the Precision Frontiers

The article outlines the recent developments in the theoretical and computational approaches to the higher-order electroweak effects needed for the accurate interpretation of MOLLER and Belle II experimental data, and shows how new-physics particles enter at the one-loop level. By analyzing the effects of $Z'$-boson on the polarization asymmetry, we show how this hypothetical interaction carrier may influence the future experimental results.