198 research outputs found
Study of the performance of hadron calorimeter using Monte Carlo techniques
No full text7-11In the present
paper, the linearity and the energy resolution of a hadron calorimeter based on
Glass Resistive Plate Chambers (GRPCs) as an active element and lead as an
absorber are examined for two operation modes, analog and digital by using
Geant4 simulation toolkit. This investigation has been carried out in order to
develop a hadron calorimeter for the future linear collider International
Linear Collider
Measurements of the production cross section and forward- backward asymmetry at centre-of-mass energies above the Z pole at LEP
No full textThe measurements of R_{b} = \sigma(e^+e^-} \to b\overline{b})/\sigma( e^+e^-} \to{m q\overline{q}) and of the b quarkforward--backward charge asymmetry,A_fb}^{b}, at centre--of--mass energies above the Z pole are described. The measurement of is performed at between 130 and 189 GeV using a b--tagging method thatexploits the relatively large decay length ofb--hadrons. The measurement of is performedusing the large statistics event sample collected at =189 GeV with a lepton--tag analysis based on the selection of prompt muons and electrons. The results at =189 GeV are: , The measurements of R b =σ( e + e − → b b ̄ )/σ( e + e − → q q ̄ ) and of the b quark forward–backward charge asymmetry, A fb b , at centre-of-mass energies above the Z pole are described. The measurement of R b is performed at s between 130 and 189 GeV using a b-tagging method that exploits the relatively large decay length of b-hadrons. The measurement of A fb b is performed using the large statistics event sample collected at s =189 GeV with a lepton-tag analysis based on the selection of prompt muons and electrons. The results at s =189 GeV are R b =0.163±0.013 (stat.) ±0.005 (syst.) , A fb b =0.61±0.18 (stat.) ±0.09 (syst.) .The measurements of Rb = sigma(e+e- -> bb~)/sigma(e+e- -> qq~) and of the b quark forward-backward charge asymmetry, A^b_fb, at centre-of-mass energies above the Z pole are described. The measurement of Rb is performed at \root{s} between 130 and 189 GeV using a b-tagging method that exploits the relatively large decay length of b-hadrons. The measurement of A^b_fb is performed using the large statistics event sample collected at \root{s}=189 GeV with a lepton-tag analysis based on the selection of prompt muons and electrons. The results at \root{s}=189 GeV are: Rb = 0.163 +/- 0.013 (stat.) +/- 0.005 (syst.), A^b_fb = 0.61 +/- 0.18 (stat.) +/- 0.09 (syst.)
Effective operators in a single- orbital
No full text25 pages, 7 figures, 5 tables, Accepted for publication in J. of Physics GInternational audienceWe present an analysis of effective operators in the shell model with up to three-body interactions in the Hamiltonian and two-body terms in electromagnetic transition operators when the nucleons are either neutrons or protons occupying a single-j orbital. We first show that evidence for an effective three-body interaction exists in the N = 50 isotones and in the lead isotopes but that the separate components of such interaction are difficult to obtain empirically. We then determine higher-order terms on more microscopic grounds. The starting point is a realistic two-body interaction in a large shell-model space together with a standard one-body transition operator, which, after restriction to the dominant orbital and with use of stationary perturbation theory, are transformed into effective versions with higher-order terms. An application is presented for the lead isotopes with neutrons in the 1g 9/2 orbital
Diagnosis of discrete-time singularly perturbed systems based on slow subsystem
No full textThis paper deals with the diagnosis of discrete-time singularly perturbed systems presenting two time scales property. Parity space method is considered to generate the fault detection residual. The focus is in two directions. First, we discuss the residual illconditioning caused by the singular perturbation parameter. Then, the use of the slow subsystem is considered to make the fault diagnosis easier. It is shown that the designed diagnostic algorithm based on reduced order model is close to the one synthesized using the full order system. The developed approach aims at reducing the computational load and the ill-conditioning for stiff residual generation problem. Two examples of application are used to demonstrate the efficiency of the proposed method
Classification of impacted mandibular third molars using cone beam computed tomography based on neurological risks: N.R.C.
No full textIntroduction: Considering the close proximity of the third molar roots and the mandibular canal, also the location of the lingual nerve and its anatomic variations, both nerves may be injured during extraction. The aim of this observational study was to optimize a classification of the relationship between the third molar and its neuroanatomical environment, mandibular canal and lingual bone plate, which is inspired from the neurological risks involving cone beam CT (CBCT) images, and to apply this classification to our sample. Materials and methods: A retrospective, observational study was performed involving 100 CBCT (171 mandibular third molars). Two medical doctors, qualified in human anatomy, independently evaluated all CBCT using coronal oblique sections. The classification was approved by agreement between both observers. After that, it was applied to our sample by one of them. The SPSS software, version 21.0 (SPSS® Inc., Chicago, Illinois, USA) was used for the statistical analysis. Results: The final consensual classification presented three Classes (A, B, L) with their four subclasses (from 1 to 4). The rare cases found in our sample were grouped separately under the name of “uncommon”, and were divided into four specific subclasses. The status of the lingual bone plate was assessed by the presence or the absence of a fenestration or a cortical thinning. In the current study, when the mandibular canal presented a direct contact with the third molar with a reduced calibre, lingual course was the most frequent anatomical situation in both genders (males 66.7%/females 70.5%). There is not a significant correlation between the proximity of the third molar to the mandibular canal neither with age nor with gender. In contrast, the proximity to the third molar is significantly associated with the course of the canal. The highest significance was found with the lingual course. Statistical analysis showed a nonsignificant correlation between the status of the lingual bone plate and the age then the gender. Discussion and conclusion: The use of the proposed classification (NRC) could be a support for clinical practice. We suggested a common language among operators and during collaboration with radiologists in order to facilitate the clinical discussion and to correlate the surgery outcomes to the CBCT classes for more adjustment of the surgical procedures
Measurement of the Topological Branching Fractions of the lepton at LEP
No full textUsing data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractions of the lepton into one, three and five charged particles to be: \begin{eqnarray*} & {\cal{B}}(\tau\rightarrow (1-prong)) & = 85.274 \pm 0.105 \pm 0.073 \% , \\ & {\cal{B}}(\tau\rightarrow (3-prong)) & = 14.556 \pm 0.105 \pm 0.076 \%, \\ & {\cal{B}}(\tau\rightarrow (5-prong)) & = \phantom{0} 0.170 \pm 0.022 \pm 0.026 \%. \end{eqnarray*} \noindent The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world average.Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractions of the τ lepton into one, three and five charged particles to be: B (τ→( 1-prong ))=85.274±0.105±0.073%, B (τ→( 3-prong ))=14.556±0.105±0.076%, B (τ→( 5-prong ))=0.170±0.022±0.026%. The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world average.Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractions of the tau lepton into one, three and five charged particles to be: B(tau->(1-prong)) = 85.274 +- 0.105 +- 0.073 %, B(tau->(3-prong)) = 14.556 +- 0.105 +- 0.076 %, B(tau->(5-prong)) = 0.170 +- 0.022 +- 0.026 %. The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world average
Measurement of the W-Pair Production Cross Section and W-Decay Branching Fractions in Interactions at = 189 GeV
No full textThe data collected by the L3 experiment at LEP at a centre-of-mass energy of are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8~pb. The total cross section for W-pair production, combining all final states, is measured to be ~pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be . The results agree with the Standard Model predictions.The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8 pb −1 . The total cross section for W-pair production, combining all final states, is measured to be σ WW =16.24±0.37 (stat.)±0.22 (syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B (W→qq)=[68.20±0.68 (stat.)±0.33 (syst.)]%. The results agree with the Standard Model predictions.The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8pb^-1. The total cross section for W-pair production, combining all final states, is measured to be sigma_WW = 16.24 +/- 0.37(stat.) +/- 0.22(syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B(W ->qq) = [68.20 +/- 0.68 (stat.) +/- 0.33 (syst.) ] %. The results agree with the Standard Model predictions
Measurements of the b(b)over-bar production cross section and forward-backward asymmetry at centre-of-mass energies above the Z pole at LEP RID C-2983-2009 RID C-4549-2008 RID C-5719-2008
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