Precision electroweak calculation of the production of a high transverse-momentum lepton pair at hadron colliders

We present a detailed study of the production of a high transverse-momentum lepton pair at hadron colliders, which includes the exact O(alpha) electroweak corrections properly matched with leading logarithmic effects due to multiple photon emission, as required by the experiments at the Fermilab Tevatron and the CERN LHC. Numerical results for the relevant observables of single Z-boson production at hadron colliders are presented. The impact of the radiative corrections is discussed in detail. The presence in the proton of a photon density is considered and the effects of the photon-induced partonic subprocesses are analyzed. The calculation has been implemented in the new version of the event generator HORACE, which is available for precision simulations of the neutral and charged current Drell-Yan processes.Comment: October 2007, 22p

Full one-loop electroweak corrections to e+e- to 3 jets at linear colliders

We describe the impact of the full one-loop electroweak terms of O(alpha_s alpha_EM^3) entering the electron-positron into three-jet cross-section from sqrt(s)=M_Z to TeV scale energies. We include both factorisable and non-factorisable virtual corrections and photon bremsstrahlung. Their importance for the measurement of alpha_S from jet rates and shape variables is explained qualitatively and illustrated quantitatively, also in presence of b-tagging.Comment: 6 pages, to appear in the proceedings of the workshop "LC09 -- e+e- Physics at the TeV scale and the Dark Matter Connection", 21-24 September 2009, Perugia (Italy). Minor corrections, references added

Comparisons of the Monte Carlo programs HORACE and WINHAC for single-W-boson production at hadron colliders

We present the comparisons of two independent Monte Carlo event generators, HORACE and WINHAC, for single-W-boson production in hadronic collisions with multiphoton effects in leptonic W decays. These comparisons were performed first at the parton level with fixed quark-beams energy, and then at the hadron level for proton-proton collisions at the LHC. In general, a good agreement between the two programs has been found. Possible sources of differences in some of the presented results are discussed. We also present and discuss the effects of including non-zero quark masses for the main single-W-boson observables at the LHC.Comment: 32 pages, 40 PostScript figure

Higgs decay into four charged leptons in the presence of dimension-six operators

We study the indirect effects of New Physics in the Higgs decay into four charged leptons, using an Effective Field Theory (EFT) approach to Higgs interactions. We evaluate the deviations induced by the EFT dimension-six operators in observables like partial decay width and various kinematic distributions, including angular observables, and compare them with the contribution of the full SM electroweak corrections. The calculation is implemented in an improved version of the event generator Hto4l, which can provide predictions in terms of different EFT-bases and is available for data analysis at the LHC. We also perform a phenomenological study in order to assess the benefits coming from the inclusion of differential information in the future analyses of very precise data which will be collected during the high luminosity phase of the LHC.Comment: 31 pages, 8 figures, 1 table. Version to appear on JHEP, expanded phenomenological section including an analysis for HL-LH

One-loop corrections to the Drell--Yan process in SANC (II). The neutral current case

Radiative corrections to the neutral current Drell--Yan-like processes are considered. Complete one-loop electroweak corrections are calculated within the SANC system. Theoretical uncertainties are discussed. Numerical results are presented for typical conditions of LHC experiments.Comment: 17 pages, 9 figures, 3 table

Multiple photon corrections to the neutral-current Drell-Yan process

Precision studies of single W and Z production processes at hadron colliders require progress in the calculation of electroweak radiative corrections. To this end, higher-order QED corrections to the neutral-current Drell-Yan process, due to multiple photon radiation in Z leptonic decays, are calculated. Particular attention is paid to the effects induced by such corrections on the experimental observables which are relevant for high-precision measurements of the W-boson mass at the Tevatron Run II and the LHC. The calculation is implemented in the Monte Carlo event generator HORACE, which is available for data analysis.Comment: 16 pages, 4 figures, 3 tables, JHEP3 styl

Higher-order QED corrections to W-boson mass determination at hadron colliders

The impact of higher-order final-state photonic corrections on the precise determination of the W-boson mass at the Tevatron and LHC colliders is evaluated. In the presence of realistic selection criteria, the shift in the W mass from a fit to the transverse mass distribution is found to be about 10 MeV in the $W \to \mu \nu$ channel and almost negligible in the $W \to e \nu$ channel. The calculation, which is implemented in a Monte Carlo event generator for data analysis, can contribute to reduce the uncertainty associated to the W mass measurement at future hadron collider experiments.Comment: 9 pages, 2 figures, 1 table, RevTe

Inverse bremsstrahlung contributions to Drell-Yan like processes

The contribution of the sub-process $\gamma q \to q' l_1\bar{l}_2$ in hadron-hadron interactions is considered. It is a part of one-loop electroweak radiative corrections for the Drell-Yan production of lepton pairs at hadron colliders. It is shown that this contribution should be taken into account aiming at the 1% accuracy of the Drell-Yan process theoretical description. Both the neutral and charged current cases are evaluated. Numerical results are presented for typical conditions of LHC experiments.Comment: 11 pages, 8 figure

Evaluation of the Theoretical Uncertainties in the Z to ll Cross Sections at the LHC

We study the sources of systematic errors in the measurement of the Z to ll cross-sections at the LHC. We consider the systematic errors in both the total cross-section and acceptance for anticipated experimental cuts. We include the best available analysis of QCD effects at NNLO in assessing the effect of higher order corrections and PDF and scale uncertainties on the theoretical acceptance. In addition, we evaluate the error due to missing NLO electroweak corrections and propose which MC generators and computational schemes should be implemented to best simulate the events.Comment: 23 pages, 52 eps figures, LaTeX with JHEP3.cls, epsfig. Added a reference, acknowledgment, and a few clarifying comments. 4/29: Changes in references, minor rewordings and misprint corrections, and one new table (Table 4) comparing CTEQ and MRST PDFs in the NNLO calculation. Version 6 adds email addresses and corrects one referenc