1,721,140 research outputs found
Characterisation of the muon beams for the Muon Ionisation Cooling Experiment
No full text"A novel single-particle technique to measure emittance has been developed and used to characterise seventeen different muon beams for the Muon Ionisation Cooling Experiment (MICE). The muon beams, whose mean momenta vary from 171 to 281 MeV\/c, have emittances of approximately 1.2-2.3 pi mm-rad horizontally and 0.6-1.0 pi mm-rad vertically, a horizontal dispersion of 90-190 mm and momentum spreads of about 25 MeV\/c. There is reasonable agreement between the measured parameters of the beams and the results of simulations. The beams are found to meet the requirements of MICE.
Bringing the ATLAS muon spectrometer to life with cosmic rays
No full textThe muon spectrometer of the ATLAS experiment at the Large Hadron Collider is the largest device ever built to track high energy particles. It has been designed to provide muon identification and measurement in the hard environment of proton-proton collisions at high energy and high luminosity at the LHC. Three toroid magnets, one in the barrel and two in the end-caps, host the particle detectors for the trigger and for precision tracking. The bending power, which ranges between 1 and 7.5 T-m, depending on the pseudorapidity, and the low amount of material crossed by the muons in the spectrometer, allow the precise determination of the transverse momentum over a wide pseudorapidity interval, |eta|<2.4, with a resolution better than 10% up to 1 TeV for |eta|<1.1. Four different types of detectors, two devoted to triggering and two to the precision momentum measurement, cover an area of 10,000 square meters and are read out by 1 million channels of electronics. Many advanced technological components are used in both the hardware and the software to control the detector status, monitor the data quality. This impressive number of elements, spread over the large volume of the spectrometer, were commissioned for many months with cosmic rays and were ready to take data when the first beam was circulated in the LHC. A systematic study of the detector’s performance was done in the following months. More than 200 million of cosmi c ray triggers were taken in different conditions, out of them 92% triggered by the muon system itself. These data have been used to map all detector elements, and to improve the understanding of the trigger, pattern recognition, and tracking, as well as to commission the calibration and alignment procedures and the data analysis software. We present the status of the muon detectors and the main results from the reconstruction of this event sample, showing that the ATLAS muon spectrometer is well advanced towards physics data taking
Search for the Standard Model Higgs with the ATLAS detector
No full textThe search for the Standard Model Higgs boson in data collected by the ATLAS experiment in 2011 and 2012 data is summarized, with emphasis on the combination of the results from all the analyzed channels
Experimental results on neutrino oscillations
No full textThe phenomenon of neutrino oscillation has been firmly established: neutrinos change their flavor in their path from their source to observers. This paper is dedicated to the description of experimental results in the oscillation field, of their present understanding and of possible future developments in experimental neutrino oscillation physics
Latest Higgs Physics Results with the ATLAS detector
No full textThe latest Higgs Physics results will be presented, providing an overview of the 7 and 8 TeV achievements before the first Run II result
Status of the ATLAS experiment
No full textThe status of the ATLAS experiment, as of September 2010, is presented, together with some highlights on the first physics result
Conditions Database and Calibration Software Framework for ATLAS Monitored Drift Tube Chambers
No full textThe size and complexity of LHC experiments raise unprecedented challenges not only in terms of detector design, construction and operation, but also in terms of software models and data persistency. One of the most challenging tasks is the calibration of the 375,000 Monitored Drift Tubes (MDTs) that will be used as precision tracking detectors in the Muon Spectrometer of the ATLAS experiment. This paper reviews the status of the MDT Calibration software and computing model. In particular, the options for a dedicated database are described
Charged-particle multiplicities in pp interactions at root s=900 GeV measured with the ATLAS detector at the LHC
No full textThe first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range vertical bar eta vertical bar 500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity eta = 0 is measured to be 1.333 +/- 0.003(stat.) +/- 0.040(syst.), which is 5-15% higher than the Monte Carlo models predict. 2010 Published by Elsevier B.V
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