1,721,078 research outputs found
Perturbative estimates of the eigenfunctions of the non-forward BFKL kernel
No full textWe discuss, within the context of first order perturbation theory, the correction to the NLO BFKL wavefunction for scattering processes with non-zero momentum transfer, arising from the fact that in NLO the kernel is not covariant under conformal transformations
On the top-antitop invariant mass spectrum at the LHC from a Higgs boson signal perspective
No full textMSSM effects in top-antitop production at the LHC
No full textWe report on a calculation of the effects of supersymmetry on the cross-section for top-antitop production at LHC. A numerical study is carried out for the ten benchmarks of the Snowmass accord. It is found that the higher order effects involving supersymmetric particles in internal loops can be as high as 6%, both for the cross-section and the (parity even) helicity asymmetry, for one particular benchmark. For other benchmarks smaller but nonetheless observable corrections are found
One-loop weak corrections to three-jet observables at the Z pole
No full textWe briefly illustrate the impact of the genuinely weak one-loop virtual terms of the O (αS αEW3) factorisable corrections to the three-jet cross section at √s = MZ. Their importance for the measurement of αS at GigaZ luminosities is emphasised
Weak corrections to gluon-induced top-antitop hadro-production
No full textWe calculate purely weak virtual one-loop corrections to the production cross section of top–antitop pairs at the Large Hadron Collider via the gluon–gluon fusion subprocess. We find very small negative corrections to the total cross section, of order ?0.6%, but significantly larger effects to the differential one, particularly in the transverse momentum distribution, of order ?5% to ?10% (in observable regions). In case of parity-conserving spin-asymmetries of the final state, corrections are typically of a few negative percent, with the exception of positive and negative peaks at +12% and ?5%, respectively (near where the tree-level predictions change sign), while those arising in parity-violating asymmetries (which are identically zero in QCD) are typically at a level of a few permille
Higgs Mass Bounds in a Triplet Model
No full textWe perform a global fit to high energy precision electroweak data in a Higgs model containing the usual isospin doublet plus a real isospin triplet. The analysis is performed in terms of the oblique parameters S, T and U and we show that the mass of the lightest Higgs boson can be as large as 2 TeV
Weak corrections and high Et jets at the Fermilab Tevatron
No full textWe calculate one-loop (purely) weak (W) corrections of [script O](alphaS2alphaW) to the partonic cross section of two jets at Tevatron and prove that they can be larger than the tree-level [script O](alphaSalphaEW) and [script O](alphaEW2) electroweak (EW) ones. At high transverse energy of the jets, all such corrections may lead to detectable effects of, e.g., -10% or so, with respect to the leading-order (LO) QCD term of [script O](alphaS2), for the highest value so far probed by Run 2, depending on the factorization/renormalization scale. Besides, they increase significantly with jet transverse energy. Hence, our results show that EW corrections may be needed to fit the standard model (SM) to present and future Tevatron jet data.<br/
Weak corrections to four-parton processes
No full textWe report on a calculation of the ‘mixed’ strong and (purely) weak corrections through the order αS2αW to parton–parton processes in all possible channels at hadron colliders entering the single jet inclusive cross section. At both Tevatron and LHC, such effects are always negligible (below permille level) in the total integrated cross section whilst they become sizable in differential rates. Specifically, if such corrections are defined with respect to the full leading-order result of [equ'n], we find that, at the FNAL accelerator, they can reach the -5% benchmark in the jet transverse energy (at the kinematical limit of the machine, rendering their detection quite difficult). At the CERN collider, in the same observable, they exceed the -10% level already at 1 TeV and can reach -40% at 4 TeV, kinematic regions where such corrections will be comfortably observable for standard luminosity. In addition, such corrections are somewhat sensitive to the factorisation/renormalisation scale choice
A light Higgs boson would invite supersymmetry
No full textIf the Higgs boson weighs about 115 GeV, the effective potential of the Standard Model becomes unstable above a scale ofabout 106 GeV. This instability may be rectified only by new bosonic particles such as stop squarks. However, avoiding theinstability requires fine-tuning of the model couplings, in particular if the theory is not to become non-perturbative before the Planck scale. Such fine-tuning is automatic in a supersymmetric model, but is lost if there are no higgsinos. A light Higgs bosonwould be prima facie evidence for supersymmetry in the top-quark and Higgs sectors
Electroweak radiative corrections to hadronic precision observables at TeV energies
No full textWe illustrate the impact of full one-loop weak corrections onto b-jet-, prompt-photon- and Z-production at Tevatron and Large Hadron Collider (LHC) <br/
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