The barrel muon chambers of the CMS detector consist of three sets of four layers of rectangular drift tubes. The performance of several prototypes was measured in a muon beam for various ...experimental conditions. Special emphasis was given to study performance aspects related to the trigger capability of the chambers.
The development of the barrel drift chambers for the CMS muon detector at the CERN
Large Hadron Collider is supported by a variety of simulation calculations, based on the GARFIELD drift chamber ...simulation program and the GEANT detector simulation package. This study surveys the results influencing the actual chamber design. The dependence of the drift cell performance on shape and position of the cell electrodes as well as on the mechanical tolerances is shown. The results obtained for space-time relation and spatial resolution are in good agreement to test beam measurements on prototypes.
Performance of a wall-less drift chamber for muon detection Faissner, H.; Moers, Th; Razen, B. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/1995, Letnik:
356, Številka:
2
Journal Article
Recenzirano
We present results on an intensive study of a muon detector prototype designed for an experiment at the LHC. The chamber has eight layers of drift tubes measuring one projection of a muon track, and ...was tested with cosmic and beam muons and in a magnetic field. Single hit detection efficiencies of 99.9% for all gas mixtures and single hit resolutions of 190 μm for the preferred gas mixture of Ar/CO
2 80% / 20% were achieved. In a magnetic field of 3 T the single hit resolution with this gas mixture decreased by 10%.
Observation of D+ --> etae + nue Shepherd, M R; Besson, D; Pedlar, T K ...
Physical review letters,
2009-Feb-27, 20090227, Letnik:
102, Številka:
8
Journal Article
Recenzirano
Using a 281 pb-1 data sample collected at the psi(3770) resonance with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D+ --> etae + nue. We also set ...upper limits for D+ --> eta'e + nue and D + --> varphie + nue that are about 2 orders of magnitude more restrictive than those obtained by previous experiments.
Using a 281 pb{-1} data sample collected at the psi(3770) with the CLEO-c detector, we present the first absolute branching fraction measurement of the decay D0-->K(-)pi(+)pi(-)e(+)nu(e) at a ...statistical significance of about 4.0 standard deviations. We find 10 candidates consistent with the decay D0-->K(-)pi(+)pi(-)e(+)nu(e). The probability that a background fluctuation accounts for this signal is less than 4.1 x 10{-5}. We find B(D0-->K(-)pi(+)pi(-)e(+)nu(e)) = 2.8{-1.1}{+1.4}(stat)+/-0.3(syst)x10{-4}. By restricting the invariant mass of the hadronic system to be consistent with K1(1270), we obtain the product of branching fractions B(D{0}-->K{1}{-}(1270)e{+}nu{e})xB(K1-(1270)-->K{-}pi{+}pi{-})=2.5{-1.0}{+1.3}(stat)+/-0.2(syst)x10{-4}. Using B(K1-(1270)-->K{-}pi{+}pi{-})=(33+/-3)%, we obtain B(D{0}-->K{1}{-}(1270)e{+}nu{e})=7.6{-3.0}{+4.1}(stat)+/-0.6(syst)+/-0.7x10{-4}. The last error accounts for the uncertainties in the measured K1-(1270)-->K{-}pi{+}pi{-} branching fractions.
We measure the decay constant f(Ds+) using the D(s+)-->l+ nu channel, where the l+ designates either a mu+ or a tau+, when the tau+ -->pi+ nu. Using both measurements we find f(Ds+)=274+/-13+/-7 MeV. ...Combining with our previous determination of f(D+), we compute the ratio f(Ds+)/f(D+)=1.23+/-0.11+/-0.04. We compare with theoretical estimates.
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