Conveners
Non-factorisable electroweak corrections at two-loop order
- Fazila Ahmadova
Description
The high-precision physics programmes of current and future colliders call for accurate theoretical predictions that include a realistic modelling of unstable particles such as the W and Z bosons or the top quark. This requires two-loop corrections to high-multiplicity, multi-scale amplitudes, whose exact computation is often beyond the reach of current techniques. The Pole Approximation (PA) offers a powerful way around this: by exploiting the resonant structure of the amplitude, it separates higher-order corrections into two gauge-invariant classes, factorisable and non-factorisable contributions. The latter arise from soft gauge-boson exchanges between the production and decay subprocesses and display a universal structure. In this talk, we will discuss the two-loop electroweak non-factorisable corrections to neutral- and charged-current single-resonance processes. We will then consider the first steps towards extending this framework to double-resonance processes such as top-quark pair, W-pair and Z-pair production, where soft exchanges connecting the two resonances introduce new structures.