Mixed Strong--Electroweak Radiative Corrections the Production of W/Z Bosons at the LHC

• Applicant: Professor Dr. Stefan Dittmaier
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414714711

The Drell-Yan-like production of W and Z bosons is among the most important classes of particle reactions at the CERN Large Hadron Collider (LHC). As standard candle processes they are used in detector calibration, they offer high-precision measurements of the effective weak mixing angle and the W-boson mass, and finally provide a window to heavy new gauge bosons W' and Z' in high-energy tails of differential distributions. It is the aim of this proposal to calculate the next-to-next-to-leading-order corrections of mixed QCD-EW type to these processes, i.e. the ones of the order O(alpha_s alpha), which represent the largest unknown type of radiative corrections in fixed-order of perturbation theory. Beyond their direct phenomenological importance in the description of W/Z production, the results of these calculations will impact predictions for other process classes as well. On the one hand, concepts, techniques, and partial results may be taken over to other reactions; one the other, a comparison of the new full results to existing approximations will help to tune or to systematically improve the approximative combination of QCD and electroweak radiative corrections. Technically and conceptually, the challenging calculations are at the forefront of perturbative calculations for particle reactions, but widely build on existing methods such as integration-by-parts and differential equations for the calculation of massive two-loop Feyman diagrams or antenna subtraction for the treatment of infrared singularities in real-emission corrections. Nevertheless, certain aspects require generalizations and further developments of existing concepts, such as the gauge-invariant treatment of intermediate W/Z resonances via the complex-mass scheme.

• DFG Programme: Research Grants