223 research outputs found
QED \otimes QCD Threshold Corrections at the LHC
We use the theory of YFS resummation to compute the size of the expected
resummed soft radiative threshold effects in precision studies of heavy
particle production at the LHC, where accuracies of 1 percent are desired in
some processes. We find that the soft QED threshold effects are at the level of
0.3 percent whereas the soft QCD threshold effects enter at the level of 20
percent and hence both must be controlled to be on the conservative side to
achieve such goals.Comment: 8 pages, no figures; improved text; improved refs. and tex
The Virtual Correction to Bremsstrahlung in High-Energy e+ e- Annihilation: Comparison of Exact Results
We have compared the virtual corrections to single hard bremsstrahlung as
calculated by S. Jadach, M. Melles, B.F.L. Ward and S.A. Yost to several other
expressions. The most recent of these comparisons is to the leptonic tensor
calculated by J.H. Kuhn and G. Rodrigo for radiative return. Agreement is found
to within a part in 10^5 or better, as a fraction of the Born cross section,
for most of the range of photon energies. The massless limits have been shown
to agree analytically to NLL order.Comment: 7 pages, 2 figures. Presented by S.A. Yost at ICHEP 2004,
International Conference on High Energy Physics, Beijing, August 16-22, 200
Threshold Corrections in Precision LHC Physics: QED otimes QCD
With an eye toward LHC processes in which theoretical precisions of 1 percent
are desired, we introduce the theory of the simultaneous YFS resummation of QED
and QCD to compute the size of the expected resummed soft radiative threshold
effects in precision studies of heavy particle production at the LHC. Our
results show that both QED and QCD soft threshold effects must be controlled to
be on the conservative side to achieve such precision goals.Comment: 4 pages, no figures; presented by B.F.L. Ward in DPF200
New Results on Precision Studies of Heavy Vector Boson Physics
We present new results for two important heavy vector boson physics
processes: (1), virtual corrections to hard bremsstrahlung which are relevant
to precision predictions for the radiative return process in Z boson production
at and beyond LEP2 energies ; and, (2), electric charge screening effects in
single W production with finite p_T, multiple photon radiation in high energy
collider physics processes. In both cases we show that we improve the
respective precision tag significantly. Phenomenological implications are
discussed.Comment: 5 pages, 2 figures; to appear in Proc. DPF200
Differential Cross Sections for Higgs Production
We review recent theoretical progress in evaluating higher order QCD
corrections to Higgs boson differential distributions at hadron-hadron
colliders
Comparison of Exact Results for the Virtual Corrections to Bremsstrahlung in Electron-Positron Annihilation at High Energies
We have compared the virtual corrections to electron-positron annihilation to
fermion pairs with single hard bremsstrahlung as calculated by S. Jadach, M.
Melles, B.F.L. Ward and S.A. Yost to several other expressions. The most recent
of these comparisons is to the leptonic tensor calculated by J.H. Kuhn and G.
Rodrigo for radiative return. Agreement is found to within or better,
as a fraction of the Born cross section.Comment: 5 pages, 2 figures. Presented at LCWS 2004, International Conference
on Linear Colliders, Paris, April 19-23, 200
Threshold Corrections in QED otimes QCD at the LHC
In some processes at the LHC, theoretical precisions of 1 percent are
desired. With an eye toward such precisions, we introduce the theory of the
simultaneous YFS resummation of QED and QCD to compute the size of the expected
resummed soft radiative threshold effects in precision studies of heavy
particle production at the LHC. Our results, that the soft QED threshold
effects are at the level of 0.3 percent whereas the soft QCD threshold effects
enter at the level of 20 percent, show that both must be controlled to be on
the conservative side to achieve such precision goals.Comment: 4 pages, no figures; presented by B.F.L. Ward at ICHEP0
Next-to-leading order predictions for WW + 1 jet distributions at the LHC
We present numerical results for the production of a pair in
association with a jet at the LHC in QCD at next-to-leading order (NLO). We
include effects of the decay of the massive vector bosons into leptons with
spin correlations and contributions from the third generation of massive
quarks. The calculation is performed using a semi-numerical method for the
virtual corrections, and is implemented in MCFM. In addition to its importance
{\it per se} as a test of the Standard Model, this process is an important
background to searches for the Higgs boson and to many new physics searches. As
an example, we study the impact of NLO corrections to jet production
on the search for a Higgs boson at the LHC.Comment: 21 pages, 9 figures; v3 published versio
Resummed Quantum Gravity
We present the current status of the a new approach to quantum general
relativity based on the exact resummation of its perturbative series as that
series was formulated by Feynman. We show that the resummed theory is UV finite
and we present some phenomenological applications as well.Comment: 4 pages, 1 figure; presented at ICHEP0
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