475 research outputs found
Sudakov Logarithm Resummation for Vector Boson Production at Hadron Colliders
A complete description of W and Z boson production at high-energy colliders
requires the resummation of large Sudakov logarithms which dominate the
production at small transverse momentum. Currently there are two techniques for
performing this resummation: impact parameter space and transverse momentum
space. We argue that the latter can be formulated in a way which retains the
advantages of the former, while at the same time allowing a smooth transition
to finite order dominance at high transverse momentum.Comment: 5 pages, LaTeX, 2 figures, epsfig, contribution to the proceedings of
the UK Phenomenology Workshop on Collider Physics, 19-24 September 1999,
Durham, to be published in J. Phys.
On the Resummation of Subleading Logarithms in the Transverse Momentum Distribution of Vector Bosons Produced at Hadron Colliders
The perturbation series for electroweak vector boson production at small
transverse momentum is dominated by large double logarithms at each order in
perturbation theory. An accurate theoretical prediction therefore requires a
resummation of these logarithms. This can be performed either directly in
transverse momentum space or in impact parameter (Fourier transform) space.
While both approaches resum the same leading double logarithms, the subleading
logarithms are, in general, treated differently. We comment on two recent
approaches to this problem, emphasising the particular subleading logarithms
resummed in each case and the numerical differences in the cross sections which
result.Comment: 13 (Latex) pages, including 5 embedded figures, uses epsfig.st
Electroweak vector boson production in joint resummation
We study the application of the joint resummation to electroweak boson
production at hadron colliders. The joint resummation formalism resums both
threshold and transverse momentum corrections to the transverse momentum
distribution at next-to-leading logarithmic accuracy. We obtain a good
description of the transverse momentum distribution of Z bosons produced at the
Tevatron collider.Comment: 5 pages, 2 figures. Talk presented by A. Kulesza at the XXXVIIth
Rencontres de Moriond `QCD and high energy hadronic interactions', Les Arcs,
Franc
The resummed Higgs boson transverse momentum distribution at the LHC
We apply QCD resummation techniques to study the transverse momentum
distribution of Higgs bosons produced via gluon-gluon fusion at the LHC. In
particular we focus on the joint resummation formalism which resums both
threshold and transverse momentum corrections simultaneously. A comparison of
results obtained in the joint and the standard recoil resummation frameworks is
presented.Comment: 9 pages, 1 figure, uses appolb.cls. Contribution to the Proceedings
of XXVII International Conference of Theoretical Physics, Ustron, Poland,
September 15-21, 2003. To appear in Acta Physica Polonica
Like-Sign W Boson Production at the LHC as a Probe of Double Parton Scattering
Double parton scattering, i.e. two parton hard scattering processes in the
same hadron-hadron collision, may constitute an important background for Higgs
and other new particle searches at the LHC. We point out that like-sign W pair
production provides a relatively clean way of searching for, and calibrating,
double parton scattering at the LHC.Comment: 10 pages, LaTeX, 5 figures, epsfi
Deep Excavations in Hard Sandy Clays for Stations and Shafts of the Athens Metro Stavros Extension
A 26 m deep excavation in hard sandy clays for the Halandri Station of the Stavros Extension of Athens Metro was completed in 2001. The excavation supporting system and the areas outside the excavation were instrumented. During the design, a finite element analysis of stresses and displacements was performed using soil parameters developed from laboratory and in-situ testing. The measured displacements had a similar distribution with depth as the calculated displacements, but were significantly smaller. An extensive finite element back-analysis was performed, in which the input parameters were varied until the magnitude and the distribution with depth of calculated displacements agreed as closely as practicable with the measured displacements. Comparison was made with displacements measured at other Stavros Extension deep excavations in similar soil. The soil parameters established from the back-analysis can be considered applicable to the design of planned further Athens Metro extensions located in similar type of soil
Non-perturbative effects and the resummed Higgs transverse momentum distribution at the LHC
We investigate the form of the non-perturbative parameterization in both the
impact parameter (b) space and transverse momentum (p_T) space resummation
formalisms for the transverse momentum distribution of single massive bosons
produced at hadron colliders. We propose to analyse data on Upsilon
hadroproduction as a means of studying the non-perturbative contribution in
processes with two gluons in the initial state. We also discuss the theoretical
errors on the resummed Higgs transverse momentum distribution at the LHC
arising from the non-perturbative contribution.Comment: 22 pages, 10 figure
Prospects for observation of double parton scattering with four-muon final states at LHCb
We study the prospects for observing double parton scattering through
four-muon final states, forming two opposite-sign muon pairs, in the LHCb
experiment in pp collisions at 14 TeV centre of mass energy. We consider two
special cases, namely double Drell-Yan and J/psi-pair production. The kinematic
properties and prospects for observing these processes are discussed. We find
that the production rate depends strongly on the origin of the four muons,
while many kinematic properties can be used to help identify the presence of
double parton scattering events.Comment: 22 pages, 12 figure
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