Stephane Keller

Electroweak radiative corrections to W and Z boson production in hadronic collisions

Some results of a calculation of electroweak radiative corrections to {ital W} and {ital Z} boson production in hadronic collisions are presented.

Implications of hadron collider observables on parton distribution function uncertainties

Standard parton distribution function sets do not have rigorously quantified uncertainties. In recent years it has become apparent that these uncertainties play an important role in the interpretation of hadron collider data. In this paper, using the framework of statistical inference, we illustrate a technique that can be used to efficiently propagate the uncertainties to new observables, assess the compatibility of new data with an initial fit, and, in case the compatibility is good, include the new data in the fit. {copyright} {ital 1998} {ital The American Physical Society}

QED radiative corrections to

The O({alpha}) radiative corrections to the process p{bar p}{r_arrow}{gamma}{sup {asterisk}}, Z{r_arrow}scr(l){sup +}scr(l){sup {minus}} (scr(l)=e, {mu}) are calculated. Factorizing the collinear singularity associated with initial state photon bremsstrahlung into the parton distribution functions, we find that initial state corrections have a much smaller effect than final state radiative corrections. Because of mass singular logarithmic terms associated with photons emitted collinear with one of the final state leptons, QED radiative corrections strongly affect the shape of the di-lepton invariant mass distribution, the lepton transverse momentum spectrum, and the forward-backward asymmetry A{sub FB}. They lead to a sizable shift in the Z boson mass extracted from data, decrease the di-lepton cross section by up to 10{percent}, and increase the integrated forward-backward asymmetry in the Z peak region by about 7{percent} at the Fermilab Tevatron. We also investigate how experimental lepton identification requirements modify the effect of the QED corrections, and study the prospects for a high precision measurement of sin{sup 2}{theta}{sub eff}{sup lept} using the forward-backward asymmetry at the CERN Large Hadron Collider. {copyright} {ital 1997} {ital The American Physical Society}

Z

We extend the phase space slicing method of Giele, Glover and Kosower for performing next-to-leading order jet cross section calculations in two important ways: we show how to include fragmentation functions and how to include massive particles. These extensions allow the application of this method to not just jet cross sections but also to cross sections in which a particular final state particle, including a

boson production and the forward backward asymmetry at hadron colliders

D

Next-to-leading order cross sections for tagged reactions

or

QCD corrections to W boson plus heavy quark production at the Tevatron

B

Determination of

-meson, is tagged.

W

Abstract The next-to-leading order QCD correction to the production of a W boson in association with a jet containing a heavy quark are presented. The calculation is fully differential in the final state particle momenta and includes the mass of the heavy quark. We study for the case of the Tevatron the sensitivity of the cross section to the strange quark distribution function, the dependence of the cross section on the heavy quark mass, the transverse momentum distribution of the jet containing the heavy quark, and the momentum distribution of the heavy quark in the jet.

boson properties at hadron colliders

Methods for measuring the W-boson properties at hadron colliders are discussed. It is demonstrated that the ratio between the W- and Z-boson observables can be reliably calculated using fixed order perturbative QCD, even when the individual W- and Z-boson observables are not. Hence, by using a measured Z-boson observable and the perturbative calculation of the ratio of the W- over Z-boson observable, we can accurately predict the W-boson observable. The use of the ratio reduces both the experimental and theoretical systematic uncertainties substantially. Compared to the currently used methods it might, at high luminosity, result in a smaller overall uncertainty on the measured W-boson mass and width. {copyright} {ital 1998} {ital The American Physical Society}