210 research outputs found
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
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
Next-to-leading Corrections to the Higgs Boson Transverse Momentum Spectrum in Gluon Fusion
We present a fully analytic calculation of the Higgs boson transverse
momentum and rapidity distributions, for nonzero Higgs , at
next-to-leading order in the infinite-top-mass approximation. We separate the
cross section into a part that contains the dominant soft, virtual, collinear,
and small--enhanced contributions, and the remainder, which is
organized by the contributions due to different parton helicities. We use this
cross section to investigate analytically the small- limit and compare
with the expectation from the resummation of large logarithms of the type
. We also compute numerically the cross section at moderate
where a fixed-order calculation is reliable. We find a -factor
that varies from , and a reduction in the scale dependence, as
compared to leading order. Our analysis suggests that the contribution of
current parton distributions to the total uncertainty on this cross section at
the LHC is probably less than that due to uncalculated higher orders.Comment: 40 pages, 10 figures, JHEP style (minor changes, added reference
Next-to-Leading order Higgs + 2 jet production via gluon fusion
We present phenomenological results for the production of a Higgs boson in
association with two jets at the LHC. The calculation is performed in the limit
of large top mass and is accurate to next-to-leading order in the strong
coupling, i.e. Comment: 13 pages, 6 figures; v2: references added, modified acknowledgments,
final version as published in JHE
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
Differential Cross Sections for Higgs Boson Production at Tevatron Collider Energies
The transverse momentum distribution is computed for inclusive Higgs
boson production at TeV. We include all-orders resummation of
large logarithms associated with emission of soft gluons at small . We
provide results for Higgs boson and masses from to 200 GeV. The
relatively hard transverse momentum distribution for Higgs boson production
suggests possibilities for improvement of the signal to background ratio.Comment: 12 pages, latex, 7 figure
SM and MSSM Higgs Boson Production: Spectra at large transverse Momentum
Strategies for Higgs boson searches require the knowledge of the total
production cross section and the transverse momentum spectrum. The large
transverse momentum spectrum of the Higgs boson produced in gluon fusion can be
quite different in the Standard Model and the Minimal Supersymmetric Standard
Model. In this paper we present a comparison of the Higgs transverse momentum
spectrum obtained using the PYTHIA event generator and the HIGLU program as
well as the program HQT, which includes NLO corrections and a soft gluon
resummation for the region of small transverse momenta. While the shapes of the
spectra are similar for the Standard Model, significant differences are
observed in the spectra of Minimal Supersymmetric Standard Model benchmark
scenarios with large tan(beta).Comment: 8 pages, 13 figure
Scalar Particle Contribution to Higgs Production via Gluon Fusion at NLO
We consider the gluon fusion production cross section of a scalar Higgs boson
in models where fermion and scalar massive colored particles are present. We
report analytic expressions for the matrix elements of , , and processes completing the calculation of the NLO QCD
corrections in these extended scenarios. The formulas are written in a complete
general case, allowing a flexible use for different theoretical models.
Applications of our results to two different models are presented: i) a model
in which the SM Higgs sector is augmented by a weak doublet scalar in the
adjoint representation. ii) The MSSM, in the limit of neglecting the
gluino contribution to the cross section.Comment: 20 pages, 5 figures. Minor changes. Refs. adde
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