AbstractThe potential for the discovery of a Standard Model Higgs boson in the mass range mH < 2 mZ in the vector boson fusion mode has been studied for the ATLAS experiment at the LHC. The ...characteristic signatures of additional jets in the forward regions of the detector and of low jet activity in the central region allow for an efficient background rejection. Analyses for the H → WW(*) and H → ττ decay modes have been performed using a realistic simulation of the expected detector performance. The results obtained demonstrate the large discovery potential in the H → WW(*) decay channel and the sensitivity to Higgs boson decays into τ-pairs in the low-mass region around 120 GeV/c2.
We propose precise and fast-track reconstruction at hadron collider experiments, for use in online trigger decisions. We describe the features of fast-track (FTK), a highly parallel processor ...dedicated to the efficient execution of a fast-tracking algorithm. The hardware-dedicated structure optimizes speed and size; these parameters are evaluated for the ATLAS experiment. We discuss some applications of high-quality tracks available to the trigger logic at an early stage, by using the LHC environment as a benchmark. The most interesting application is online selection of b-quarks down to very low transverse momentum, providing interesting hadronic samples: examples are Z/sup 0/spl rarr//bb~, potentially useful for jet calibration, and multi-b final states for supersymmetric Higgs searches. The paper is generated from outside the ATLAS experiment and has not been discussed by the ATLAS collaboration.
A method to study light attenuation effects in wavelength shifting fibres Cavasinni, V; Del Prete, T; Flaminio, V ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2004, Letnik:
517, Številka:
1
Journal Article
Recenzirano
The quality of wavelength shifting fibres depends on two basic parameters: the transparency of the core material, polystyrene, and the reflection coefficients at the fibre internal interfaces ...(core–clad and clad–clad in double-clad fibres). We have developed a model to parameterize these effects. The model has been applied to study the light attenuation in fibres used in the ATLAS hadronic calorimeter (TILE Calorimeter), as well as in the ones produced by several firms.
A PMT-Block test bench Adragna, P.; Antonaki, A.; Boudagov, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2006, Letnik:
564, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called
PMT-Block. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its ...divider and a
3-in-1 card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterization are described in detail in this report. The results obtained in the test of about 10
000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.
A device to characterize optical fibres Bosi, F.; Burdin, S.; Cavasinni, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2002, Letnik:
485, Številka:
3
Journal Article
Recenzirano
Odprti dostop
ATLAS is a general purpose experiment approved for the LHC collider at CERN. An important component of the detector is the central hadronic calorimeter; for its construction more than 600,000 Wave ...Length Shifting fibres (corresponding to a total length of
1120
km
) have been used. We have built and put into operation a dedicated instrument for the measurement of light yield and attenuation length over groups of 20 fibres at a time. The overall accuracy achieved in the measurement of light yield (attenuation length) is 1.5% (3%). We also report the results obtained using this method in the quality control of a large sample of fibres.
The results of an experiment searching for the difference Delta g in the free-fall acceleration of luminum and copper, in vacuum, obtained on the earth in a differential Galileo type measurement are ...reported. Within the sensitivity of the measurement, Delta g/g = 7.2 x 10 exp -10, no g-universality violation has been observed. (Author)
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution ...acoustic and optical observations between 70 and 170
m above the sea bed at 2475
m. The ADCP measured downward vertical currents of magnitudes up to 0.03
m
s
−1 in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35
m
s
−1. These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep dense-water formation occurred in the Ligurian subbasin, thus providing a possible explanation for these observations. However, the 10–20 days quasi-periodic episodes of high levels of acoustic reflection, light and large vertical currents continuing into the summer are not direct evidence of this process. It is hypothesized that the main process allowing for suspended material to be moved vertically later in the year is local advection, linked with topographic boundary current instabilities along the rim of the ‘Northern Current’.
► We describe yearlong optical and acoustic data from the deep-Mediterranean. ► Observations are made near the continental slope foot, near dense-water formation. ► Optics (bioluminescence), acoustics (plankton) and currents show enhanced bursts. ► Bursts are related to dense-water formation and enhanced boundary current activity.
Test beam results of the NOMAD electromagnetic calorimeter are presented showing linearity, signal uniformity, energy and position resolution measured in an electron beam. Tests were also performed ...placing the calorimeter in a magnetic field of 0.4 T. Results on the π rejection obtained using a combined measurement of preshower/electromagnetic calorimeter are found to be in good agreement with the project expectations. Finally the calorimeter response to the muons is discussed.
Measurements have been carried out on light yield and attenuation length in glass capillaries filled with new liquid scintillators (LS) and compared with analogous measurements made on 0.5 mm ...diameter plastic fibres Kuraray SCSF-38 and 3HF. It is found that, at a distance of 1 m, the light output in the capillary filled with green LS based on 1-methylnaphthalene doped with a new dye 3M15 is greater by a factor of 2 to 3 than for plastic fibres. A tracking detector consisting of a capillary bundle read out by a 100 channel position-sensitive microchannel plate photomultiplier (2MCP-100) has been built and tested in the laboratory using a cosmic ray trigger. A comparison has been made between the performance of such a detector and that of a similar one, read out by a 96 channel Philips XP1724/A photomultiplier. It was found that a bundle made of 20 μm diameter capillaries with a tapered end giving a magnification of 2.56, filled with the new IPN+3M15 liquid scintillator, read out by the 2MCP-100, provides a space resolution of
σ = 170
μm, a two-track resolution of the same value and a hit density of
n = 1.9/mm for tracks crossing the detector at a distance of 20 cm from the photocathode. If the same detector is read out by the Philips XP1724/A, the space resolution becomes 200 μm, the two-track resolution 600 μm and the hit density
n = 1.7/mm. The worse performance in the latter case is caused by the larger crosstalk compared with that of the 2MCP-100 PSPM. The results indicate that a LS-filled capillary detector is a very promising device for fast fibre tracking.
PDF
