U. Baur

Probing the Higgs self-coupling at hadron colliders using rare decays

We investigate Higgs boson pair production at hadron colliders for Higgs boson masses mH ≤ 140 GeV and rare decay of one of the two Higgs bosons. While in the Standard Model the number of events is quite low at the LHC, a first, albeit not very precise, measurement of the Higgs self-coupling is ˜

Electroweak radiative corrections to neutral current Drell-Yan processes at hadron colliders

We calculate the complete electroweak O(alpha) corrections to pp, pbar p -> l+l- X (l=e, mu) in the Standard Model of electroweak interactions. They comprise weak and photonic virtual one-loop corrections as well as real photon radiation to the parton-level processes q bar q -> gamma,Z -> l+l-. We study in detail the effect of the radiative corrections on the l+l- invariant mass distribution, the cross section in the Z boson resonance region, and on the forward-backward asymmetry, A_FB, at the Fermilab Tevatron and the CERN Large Hadron Collider. The weak corrections are found to increase the Z boson cross section by about 1%, but have little effect on the forward-backward asymmetry in the Z peak region. Threshold effects of the W box diagrams lead to pronounced effects in A_FB at m(l+l-) approx 160 GeV which, however, will be difficult to observe experimentally. At high di-lepton invariant masses, the non-factorizable weak corrections are found to become large.

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.

Measuring the Higgs boson self-coupling at the Large Hadron Collider

Inclusive Standard Model Higgs boson pair production and subsequent decay to same-sign dileptons via weak gauge W bosons at the CERN Large Hadron Collider has the capability to determine the Higgs boson self-coupling, . The large top quark mass limit is found not to be a good approximation for the signal if one wishes to utilize differential distributions in the analysis. We find that it s hould be possible at the LHC with design luminosity to establish that the Standard Model Higgs boson has a non-zero self-coupling and that = SM can be restricted to a range of 0–3.7 at 95% confidence level if its mass is between 150 and 200 GeV.

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

The processes p{anti p}{r_arrow}Z{gamma}+X{r_arrow}scr(l){sup +}scr(l){sup {minus}}{gamma}+X (scr(l)=e,{mu}) and p{anti p}{r_arrow}Z{gamma}+X{r_arrow}{bar {nu}}{nu}{gamma}+X are calculated to O({alpha}{sub s}) for general ZZ{gamma} and Z{gamma}{gamma} couplings. The impact of O({alpha}{sub s}) QCD corrections on the observability of ZZ{gamma} and Z{gamma}{gamma} couplings in Z{gamma} production at the Fermilab Tevatron and the CERN Large Hadron Collider (LHC) is discussed. {copyright} {ital 1998} {ital The American Physical Society}

boson production and the forward backward asymmetry at hadron colliders

We present a calculation of the complete electroweak O(alpha) corrections to pp/ppbar -> W+/- -> l+/- nu (l=e, mu) in the Standard Model of electroweak interactions, focusing on those corrections which do not contribute in the pole approximation. We study in detail the effect of these corrections on the transverse mass distribution, the W-width measurement, and the transverse mass ratio and cross section ratio of W and Z bosons.

QCD corrections and anomalous couplings in

The process

Z \gamma

{\mathit{pp}}^{(\mathrm{\ensuremath{-}})}

production at hadron colliders

\ensuremath{\rightarrow}