5,244 research outputs found
Diffractive Higgs boson production at Tevatron and LHC: an experimental review
We discuss the different models of central diffractive production of the
Higgs boson at the Tevatron and the LHC. We also describe how the models can be
tested using diffractive production data being taken at the Tevatron. We
finally discuss the advantages of using diffractive events to reconstruct the
mass of the Higgs boson especially at the LHC.Comment: short review to be published in Mod. Phys. Let
Inclusive Higgs boson and dijet production via Double Pomeron exchange
We evaluate Higgs boson and dijet cross-sections at the Tevatron collider via
Double Pomeron exchange when accompanying particles in the central region are
taken into account. Such {\it inclusive} processes, normalized to the observed
dijet rate observed at run I, noticeably increase the predictions for tagged
(anti)protons in the run II with respect to {\it exclusive} ones, with the
potentiality of Higgs boson detection.Comment: 6pages, 4 figure
Measurement of the inclusive jet cross-section in pp collisions at √s=2.76 TeV and comparison to the inclusive jet cross-section at √s=7 TeV using the ATLAS detector
The inclusive jet cross-section has been measured in proton–proton collisions at √s=2.76 TeV in a dataset corresponding to an integrated luminosity of 0.20 pb−1 collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-kt algorithm with two radius parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section is presented as a function of the jet transverse momentum pT and jet rapidity y, covering a range of 20≤pT<430 GeV and |y|<4.4. The ratio of the cross-section to the inclusive jet cross-section measurement at √s=7 TeV, published by the ATLAS Collaboration, is calculated as a function of both transverse momentum and the dimensionless quantity xT=2pT/√s, in bins of jet rapidity. The systematic uncertainties on the ratios are significantly reduced due to the cancellation of correlated uncertainties in the two measurements. Results are compared to the prediction from next-to-leading order perturbative QCD calculations corrected for non-perturbative effects, and next-to-leading order Monte Carlo simulation. Furthermore, the ATLAS jet cross-section measurements at √s=2.76 TeV and √s=7 TeV are analysed within a framework of next-to-leading order perturbative QCD calculations to determine parton distribution functions of the proton, taking into account the correlations between the measurements
Electronics and Trigger developments for the Diffractive Physics Proposal at 220 m from LHC-ATLAS
The instrumentation consists of two sets of Roman Pots installed respectively at 216 and 224m on both sides from the ATLAS IP to measure with precision the position (< 10 micrometers) and the timing (< 5ps) of the two back to back diffracted protons tracks. Each Roman Pot is equipped with several planes of Silicon strips detectors read out by a new version of the ATLAS Silicon tracker ABCD readout chip with a longer latency (6.4 microseconds) and fast OR outputs defining a track segment. Theses inputs are to be combined in time with the ATLAS level 1 trigger accept signal. In addition, these tracks are time filtered with a very fast timing detector (MCP-PMT) allowing to constraint further at the level 2 the position of the IP within a one millimetre precision., The description of the electronics and trigger system as well as the various technical issues associated with such challenging experiments (clocks, cabling,, time monitoring) will be presented
Regge Analysis of Diffractive and Leading Baryon Structure Functions from DIS
In this paper we present a combined analysis of the H1 data on leading baryon
and diffractive structure functions from DIS, which are handled as two
components of the same semi-inclusive process. The available structure function
data are analyzed in a series of fits in which three main exchanges are taking
into account: pomeron, reggeon and pion. For each of these contributions, Regge
factorization of the correspondent structure function is assumed. By this
procedure, we extract information about the interface between the diffractive,
pomeron-dominated, region and the leading proton spectrum, which is mostly
ruled by secondary exchanges. One of the main results is that the relative
reggeon contribution to the semi-inclusive structure function is much smaller
than the one obtained from a analysis of the diffractive structure function
alone.Comment: ps file, 22 pages, 5 figures. Totally revised version with major
changes, to appear in Physical Review
Tevatron-for-LHC Report of the QCD Working Group
The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse
femtobarn of high-transverse momentum data. Such a dataset allows for the first
precision (i.e. comparisons between theory and experiment at the few percent
level) tests of QCD at a hadron collider. While the Large Hadron Collider has
been designed as a discovery machine, basic QCD analyses will still need to be
performed to understand the working environment. The Tevatron-for-LHC workshop
was conceived as a communication link to pass on the expertise of the Tevatron
and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD
Working Group focussed on important aspects of QCD at hadron colliders: jet
definitions, extraction and use of Parton Distribution Functions, the
underlying event, Monte Carlo tunes, and diffractive physics. This report
summarizes some of the results achieved during this workshop.Comment: 156 pages, Tevatron-for-LHC Conference Report of the QCD Working
Grou
Enzymatically-synthesized xylo-oligosaccharides laurate esters as surfactants of interest
Lipase-catalyzed synthesis of xylo-oligosaccharides esters from pure xylobiose, xylotriose and xylotetraose in the presence of vinyl laurate was investigated. The influence of different experimental parameters such as the loading of lipase, the reaction duration or the use of a co-solvent was studied and the reaction conditions were optimized with xylobiose. Under the best conditions, a regioselective esterification occurred to yield a monoester with the acyl chain at the OH-4 of the xylose unit at the non-reducing end. Surface-active properties of these pure xylo-oligosaccharides fatty esters have been evaluated. They display interesting surfactant activities that differ according to the degree of polymerization (DP) of the glycone moiety. © 202
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