2,222 research outputs found
Dijet rates with symmetric E_t cuts
We consider dijet production in the region where symmetric cuts on the
transverse energy, , are applied to the jets. In this region
next-to--leading order calculations are unreliable and an all-order resummation
of soft gluon effects is needed, which we carry out. Although, for illustrative
purposes, we choose dijets produced in deep inelastic scattering, our general
ideas apply additionally to dijets produced in photoproduction or processes and should be relevant also to the study of prompt di-photon
spectra in association with a recoiling jet, in hadron-hadron processesComment: 28 pages, 4 figure
Azimuthal correlation in DIS
We introduce the azimuthal correlation for the deep inelastic scattering
process. We present the QCD prediction to the level of next-to-leading log
resummation, matching to the fixed order prediction. We also estimate the
leading non-perturbative power correction. The observable is compared with the
energy-energy correlation in e+e- annihilation, on which it is modelled. The
effects of the resummation and of the leading power correction are both quite
large. It would therefore be particularly instructive to study this observable
experimentally.Comment: 33 pages, 4 figures, JHEP class included. One figure and some
clarifications adde
Semi-numerical resummation of event shapes
For many event-shape observables, the most difficult part of a resummation in
the Born limit is the analytical treatment of the observable's dependence on
multiple emissions, which is required at single logarithmic accuracy. We
present a general numerical method, suitable for a large class of event shapes,
which allows the resummation specifically of these single logarithms. It is
applied to the case of the thrust major and the oblateness, which have so far
defied analytical resummation and to the two-jet rate in the Durham algorithm,
for which only a subset of the single logs had up to now been calculated.Comment: 29 pages, 7 figures. Version 2 adds some clarifications, a reference,
as well as corrections to the subleading fixed-order coefficients and to
figures 4 and
Non-global logarithms and jet algorithms in high-pT jet shapes
We consider jet-shape observables of the type proposed recently, where the
shapes of one or more high-pT jets, produced in a multi-jet event with definite
jet multiplicity, may be measured leaving other jets in the event unmeasured.
We point out the structure of the full next-to-leading logarithmic resummation
specifically including resummation of non-global logarithms in the leading-Nc
limit and emphasising their properties. We also point out differences between
jet algorithms in the context of soft gluon resummation for such observables.Comment: 22 pages, 4 figures. Title and a few words changed. Several typos
corrected. Version accepted by JHE
Calibration of the ATLAS electromagnetic calorimeter using calibration hits
In the present note a method to determine the electron energy from the energies measured in an electron cluster is discussed. The method is based on a detailed Monte-Carlo simulation (labeled \textit{Calibration Hits}) of electrons in the ATLAS detector in which also the energies deposited in the passive and dead materials are recorded. It allows also to compute the different contributions (energy deposited in front, in and behind the Accordion) to the total electron energy. To better understand the various contributions to the energy reconstruction three rounds of simulations have been performed: electrons hitting the middle cell centre, electrons spread uniformly over a cell in absence of magnetic field and electrons spread uniformly over a cell in presence of magnetic field. The method is applied to the Barrel calorimeter and to electrons. Its extension to the End Caps and to photons does not pose problems. In the operative ATLAS conditions an energy resolution sampling term varying from 9.9 at =0.3 and 16.8 at =1.2 is obtained. The linearity varies between 0.1 and 0.4 in the energy interval 10-100GeV over the same range
A general method for the resummation of event-shape distributions in e⁺ e− annihilation
We present a novel method for resummation of event shapes to next-to-next-to-leading-logarithmic (NNLL) accuracy. We discuss the technique and describe its implementation in a numerical program in the case of e + e − collisions where the resummed prediction is matched to NNLO. We reproduce all the existing predictions and present new results for oblateness and thrust major
Resummed event-shape variables in DIS
We complete our study of resummed event-shape distributions in DIS by
presenting results for the class of observables that includes the current jet
mass, the C-parameter and the thrust with respect to the current-hemisphere
thrust axis. We then compare our results to data for all observables for which
data exist, fitting for alpha_s and testing the universality of
non-perturbative 1/Q effects. A number of technical issues arise, including the
extension of the concept of non-globalness to the case of discontinuous
globalness; singularities and non-convergence of distributions other than in
the Born limit; methods to speed up fixed-order Monte Carlo programs by up to
an order of magnitude, relevant when dealing with many x and Q points; and the
estimation of uncertainties on the predictions.Comment: 41 page
From P4 medicine to P5 medicine: transitional times for a more human-centric approach to AI-based tools for hospitals of tomorrow
Within the debate on shaping future clinical services, where different
robotics and artificial intelligence (AI) based technologies are
integrated to perform tasks, the authors take the chance to provide
an interdisciplinary analysis required to validate a tool aiming at
supporting the melanoma cancer diagnosis. In particular, they focus
on the ethical-legal and technical requirements needed to address the
Assessment List on Trustworthy AI (ALTAI), highlighting some pros
and cons of the adopted self-assessment checklist. The dialogue
stimulates additionally remarks on the EU regulatory initiatives on AI
in the healthcare systems
A high-resolution RNA expression atlas of Retinitis Pigmentosa genes in the human and mouse retinas
PURPOSE. Retinitis pigmentosa (RP) is one of the leading causes of visual handicap in the world population and is characterized by high genetic heterogeneity. The study of the disease mechanisms and the development of efficient therapeutic approaches have mostly relied on the availability of animal models for this condition, so far. Nevertheless, little information is available about the RNA expression profiles of RP genes in the human retina. An expression atlas of 34 known RP genes in human and murine retinas was generated to overcome this lack of information. METHODS. Appropriate templates were retrieved for 34 RP genes that were used to perform RNA in situ hybridization studies on human and murine adult eyes. RESULTS. Most of the genes displayed similar patterns between human and mouse retina. Different expression patterns were observed for the CNGB1, USH2A, and FSCN2 genes, compared with those in previously reported profiles. In addition, different expression profiles were detected for the RPGR, CA4, PAP1, RGR, and RLBP1 genes in human and mouse retinas. CONCLUSIONS. The first gene expression atlas has been generated of RP genes in human and murine retinas. Differences observed in the expression patterns of some genes in humans and mice, will open new perspectives on the function of these genes and their putative roles in disease pathogenesis
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