Gauge Boson Production at Hadron Colliders.

摘要

Electroweak (EW) gauge boson production via the Drell-Yan (DY) process plays a crucial role in studying physics at hadron colliders. It can be used in the calibration of detectors, monitoring partonic luminosity, constraining parton distribution functions and probing new physics. All these tasks rely on accurate predictions obtained by precision calculation to higher orders in perturbation theory. It is imperative to ensure the availability of theoretical calculations to the high energy physics community through their implementation in flexible numerical codes.;We introduce an updated version of the simulation code FEWZ (F ully Exclusive W and Z Production) for hadronic production of EW bosons at next-to-next-to-leading-order (NNLO) in QCD. The new version offers more options for customization and features a significantly improved integration routine. In the latest upgrade of FEWZ, we include the electroweak correction to Z production at next-to-leading-order (NLO), eliminating the need to unfold the photon final-state-radiation effect when comparing to experimental data.;Results from codes like FEWZ which depend solely on fixed-order calculations are not always reliable when large logarithms arising from multiple scales destroy the convergence of the perturbation expansion. The distribution of low transverse momentum (pT) of EW gauge bosons is such an example; it is important in many studies within and beyond the Standard Model (SM). We present NNLO results for an exclusive soft function that appears in a recently developed factorization theorem for p T distributions. We give results and relevant technical details for its calculation, which are necessary for achieving low p T resummation at next-to-next-to-leading-logarithmic (NNLL) accuracy.;In addition to the standard Z, new gauge bosons which arise in many extensions of the SM, can show up in the high energy tail of the DY process. We study the potential of the LHC and future low-energy experiments to precisely measure the underlying model parameters of a Z'. We demonstrate the importance of off-peak LHC data and a future precision measurement of low-energy Møller scattering for removing sign and scaling degeneracies between couplings, which occur if only on-peak LHC data is studied.