3,595 research outputs found
Luminosity measurement method for the LHC: The detector requirements studies
Absolute normalisation of the LHC measurements with a precision of O(1%) is
desirable but beyond the reach of the present LHC detectors. This series of
papers proposes and evaluates a measurement method capable to achieve such a
precision target. In our earlier paper we have selected the phase-space region
where the lepton pair production cross section in pp collisions at the LHC can
be controlled with < 1 % precision and is large enough to reach a comparable
statistical accuracy of the absolute luminosity measurement on the day-by-day
basis. In the present one the performance requirements for a dedicated
detector, indispensable to efficiently select events in the proposed
phase-space region, are discussed.Comment: 26 pages, 13 figure
Measuring sigma(e^+e^- \to hadrons) using tagged photon
We propose to use events with radiated photons in e^+e^- collisions to
measure the total cross section of e^+ e^- \to hadrons as a function of the
center of mass energy. The Monte Carlo simulation for the collider DAPHNE shows
that a competitive accuracy can be achieved with this method.Comment: revtex, 13 page
Z-boson as "the standard candle" for high precision W-boson physics at LHC
In this paper we propose a strategy for measuring the inclusive W-boson
production processes at LHC. This strategy exploits simultaneously the unique
flexibility of the LHC collider in running variable beam particle species at
variable beam energies, and the configuration flexibility of the LHC detectors.
We propose their concrete settings for a precision measurement of the Standard
Model parameters. These dedicated settings optimise the use of the Z boson and
Drell-Yan pair production processes as ``the standard reference candles''. The
presented strategy allows to factorise and to directly measure those of the QCD
effects which affect differently the W and Z production processes. It reduces
to a level of 10^{-4} the impact of uncertainties in the partonic distribution
functions (PDFs) and in the transverse momentum of the quarks on the
measurement precision. Last but not the least, it reduces by a factor of 10 an
impact of systematic measurement errors, such as the energy scale and the
measurement resolution, on the W-boson production observables.Comment: 20 pages, 4 figure
Luminosity Measurement Method for LHC: The theoretical precision and the experimental challenges
This is the first of the series of papers which present a precision method of the day-by-day monitoring of the absolute LHC luminosity. The method is based on the measurement of the rate of coplanar lepton pairs produced in peripheral collisions of the beams' particles. In the present paper we evaluate the modeling precision of the lepton pair production processes in proton-proton collisions, optimize the measurement region to achieve better than 1% accuracy of the predicted rates, and discuss the experimental challenges to filter out the luminosity monitoring lepton pairs at LHC
Location of the narrowest area of the pharynx regarding body mass index and obstructive sleep apnoea severity
Background: Among authors studying morphological determinants of the obstructive sleep apnoea (OSA) controversies exist on the location of the narrowest area within the pharynx, critical for development of obstruction. Those disagreements primarily revolve around differences between obese and nonobese OSA patients. Determination whether the location and size of the narrowest area within the pharynx differentiates the obese and nonobese OSA patients.
Materials and methods: A population of 55 subjects was investigated after being diagnosed with OSA in the Polysomnography Laboratory of the Department and Clinic of Otolaryngology in the Medical University of Warsaw, Poland. Additionally a head computed tomography (CT) was performed in all the subjects. The CT images were used to do several crucial measurements which described the geometry of the facial skeleton as well as soft tissues of the head. The obtained results were correlated with apnoea-hypopnoea index (AHI) and body mass index (BMI) values. The data were statistically analysed.
Results: The distance between the hard palate and posterior pharyngeal wall parallel to the horizontal plane as well as the shortest distance between the soft palate and posterior pharyngeal wall significantly differentiated patients in the subgroups by AHI but not by BMI.
Conclusions: Pharyngeal obstruction at the level of the hard and soft palate differentiates patients with severe OSA from patients with mild and moderate OSA regardless of BMI
Luminosity Measurement Method for the LHC: Event Selection and Absolute Luminosity Determination
Absolute normalisation of the LHC measurements with O(1%) precision and their
relative normalisation, for the data collected at variable centre-of-mass
energies, or for variable beam particle species, with O(0.1%) precision is
crucial for the LHC experimental programme but presently beyond the reach for
the general purpose LHC detectors. This paper is the third in the series of
papers presenting the measurement method capable to achieve such a goal.Comment: 31 pages, 15 figure
Spectroscopy at B-factories Using Hard Photon Emission
The process of hard photon emission by initial electrons (positrons) at
B-factories is discussed. It is shown that studies of the bottomonium
spectroscopy will be feasible for the planned integrated luminosity of the
B-factory experiments.Comment: 9 pages, Latex, 1 fugure, Submitted to Int.Jour.Mod.Phys.
Cross Section Ratios between different CM energies at the LHC: opportunities for precision measurements and BSM sensitivity
The staged increase of the LHC beam energy provides a new class of
interesting observables, namely ratios and double ratios of cross sections of
various hard processes. The large degree of correlation of theoretical
systematics in the cross section calculations at different energies leads to
highly precise predictions for such ratios. We present in this letter few
examples of such ratios, and discuss their possible implications, both in terms
of opportunities for precision measurements and in terms of sensitivity to
Beyond the Standard Model dynamics.Comment: 19 pages, 9 figure
Scedosporium and Pseudallescheria low molecular weight metabolites revealed by database search
The potential of mMass software search tool with new compound libraries was demonstrated on metabolomics of Scedosporium prolificans, S. apiospermum and Pseudallescheria boydii sensu stricto. Cyclic peptides pseudacyclins, small molecular weight tyroscherin analogues and various lipids were annotated by open source mass spectometry tool utilising accurate matrix-assisted laser desorption/ionisation mass spectral data of intact fungal spores. Electrospray ionisation combined with tandem mass spectrometry was used for monohexosylceramide characterisation in fungal extracts
Tagged-photon events in polarized DIS process
Deep-inelastic events for the scattering of the longitudinally polarized
electron by polarized proton with tagged collinear photon radiated from
initial-state electron are considered. The corresponding cross-section is
derived in the Born approximation. The model-independent radiative corrections
to the Born cross-section are also calculated. Obtained result is applied to
the case of elastic scattering.Comment: 14 pages, 2 figures, submitted to JET
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