3,674 research outputs found
Studies of Top Quark properties at the LHC
The LHC collider plans to start in 2007, after which millions of top quarks
will be produced at the collision points. In the first period of data taking
these events will provide an essential calibration tool for the ATLAS and CMS
detectors. During a later stage, as part of the precision measurement
programme, both detectors will determine the top mass and properties like spin,
charge and couplings. Top physics also plays a central role in the search for
new particles, both as source of a possible signal and as source of
background.}Comment: Moriond conference writeu
QED radiative corrections for elastic e(mu)p scattering in hadronic variables
A numerical analysis of QED radiative corrections for elastic e(mu)p
cattering in hadronic variables at energies of the current experiment at JLab
is performed. The explicit formulas from the review of Akhundov et al.
resulting from the integration over the phase space of leptonic variables plus
photon are used to obtain the values of the cross sections and the radiative
correction factor for unpolarized lepton-proton scattering. Our numerical
results agree with the corresponding results arising from the formulas of
Afanasev et al.Comment: 4 Pages, 4 figure
Special Supersymmetric features of large invariant mass unpolarized and polarized top-antitop production at LHC
We consider the top-antitop invariant mass distributions for production of
unpolarized and polarized top quark pairs at LHC, in the theoretical framework
of the MSSM. Assuming a "moderately" light SUSY scenario, we derive the leading
logarithmic electroweak contributions at one loop in a region of large
invariant mass, TeV, for the unpolarized differential
cross section and for the differential longitudinal top
polarization asymmetry . We perform a realistic evaluation of
the expected uncertainties of the two quantities, both from a theoretical and
from an experimental point of view, and discuss the possibility of obtaining,
from accurate measurements of the two mass distributions, stringent consistency
tests of the model, in particular identifications of large effects.Comment: 23 pages, 9 eps figure
After the Standard Model: New Resonances at the LHC
Experiments will soon start taking data at CERN's Large Hadron Collider (LHC)
with high expectations for discovery of new physics phenomena. Indeed, the
LHC's unprecedented center-of-mass energy will allow the experiments to probe
an energy regime where the standard model is known to break down. In this
article, the experiments' capability to observe new resonances in various
channels is reviewed.Comment: Preprint version of a Brief Review for Modern Physics Letters A.
Changes w.r.t. the fully corrected version are smal
Deterministic Annealing as a jet clustering algorithm in hadronic collisions
We show that a general purpose clusterization algorithm, Deterministic
Annealing, can be adapted to the problem of jet identification in particle
production by high energy collisions. In particular we consider the problem of
jet searching in events generated at hadronic colliders. Deterministic
Annealing is able to reproduce the results obtained by traditional jet
algorithms and to exhibit a higher degree of flexibility.Comment: 13 pages, 6 figure
On saturation of charged hadron production in pp collisions at LHC
First results on charged hadron transverse momentum spectra in pp collisions
obtained by the CMS Collaboration at LHC were analyzed in z-scaling approach.
The first LHC data confirm z-scaling. The saturation regime of the scaling
function psi(z) observed in pp and antp-pp interactions at lower energy sqrt s
= 19-1960 GeV is verified. The saturation of psi(z) for charged hadrons is
found down to z=0.05 at the highest energy sqrt s = 2360 GeV reached till now
at colliders. A microscopic scenario of hadron production is discussed in
connection with search for new signatures of phase transitions in hadron
matter. Constituent energy loss and its dependencies on the transverse momentum
of charged hadrons and collision energy are estimated. The beam energy scan at
LHC in the saturation region is suggested.Comment: LaTeX, 6 pages, 6 figure
Jet analysis by Deterministic Annealing
We perform a comparison of two jet clusterization algorithms. The first one
is the standard Durham algorithm and the second one is a global optimization
scheme, Deterministic Annealing, often used in clusterization problems, and
adapted to the problem of jet identification in particle production by high
energy collisions; in particular we study hadronic jets in WW production by
high energy electron positron scattering. Our results are as follows. First, we
find that the two procedures give basically the same output as far as the
particle clusterization is concerned. Second, we find that the increase of CPU
time with the particle multiplicity is much faster for the Durham jet
clustering algorithm in comparison with Deterministic Annealing. Since this
result follows from the higher computational complexity of the Durham scheme,
it should not depend on the particular process studied here and might be
significant for jet physics at LHC as well.Comment: 15 pages, 4 figure
Effect evaluation of a vocational rehabilitation program for young adults with chronic physical conditions at risk for unemployment:A controlled clinical trial
Background: The work participation of young adults with chronic physical conditions lag behind compared to healthy age-mates. ‘At Work’ is a vocational rehabilitation intervention provided by occupational therapists, that supports them for entering the competitive labour market after graduating post-secondary education. Aim: To evaluate the effects of ‘At Work’ on self-efficacy, work-ability and employment status as compared to usual care. Materials and methods: In total, 88 young adults were included in a multicentre controlled trial; 49 entered ‘At Work’, 39 received usual care. GEE-analyses were applied. Results:Scores on all outcome measures substantially improved over time in the intervention group, but no significant effects were found as compared to the control group. The effect on general self-efficacy showed a positive trend in favour of the intervention group. Conclusions and significance: Unlike previous study results pointing to positive outcomes of At Work’, the current study did not support the effectiveness of this program on work-related self-efficacy, work-ability and paid employment, as compared to usual care. Yet, we did find an indication for positive intervention effect on general self-efficacy, which is known to be an important capacity to achieve social participation.</p
Standard Model Physics at LEP
Selected topics on precision tests of the Standard Model of the Electroweak
and the Strong Interaction at the LEP collider are presented,
including an update of the world summary of measurements of ,
representing the state of knowledge of summer 1999. This write-up of lecture
notes consists of a reproduction of slides, pictures and tables, supplemented
by a short descriptive text and a list of relevant references.Comment: lecture given at Intern. Summer School at Nijmegen, August 1999, 44
pages, 36 (mostly coloured) figures, LaTeX, needs crckapb.st
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