Jurnal Edukasi
Not a member yet
4879 research outputs found
Sort by
Measurement of the top quark mass using proton-proton data at sqrt(s) = 7 and 8 TeV
No full textSubmitted to Phys. Rev. D ; see paper for full list of authorsInternational audienceA new set of measurements of the top quark mass are presented, based on the proton-proton data recorded by the CMS experiment at the LHC at sqrt(s) = 8 TeV corresponding to a luminosity of 19.7 inverse femtobarns. The top quark mass is measured using the lepton+jets, all-jets and dilepton decay channels, giving values of 172.35 +/- 0.16 (stat) +/- 0.48 (syst) GeV, 172.32 +/- 0.25 (stat) +/- 0.59 (syst) GeV, and 172.82 +/- 0.19 (stat) +/- 1.22 (syst) GeV, respectively. When combined with the published CMS results at sqrt(s) = 7 TeV, they provide a top quark mass measurement of 172.44+/- 0.13 (stat) +/- 0.47 (syst) GeV. The top quark mass is also studied as a function of the event kinematical properties in the lepton+jets decay channel. No indications of a kinematic bias are observed and the collision data are consistent with a range of predictions from current theoretical models of ttbar production
Quantum singular complete integrability
No full textInternational audienceWe consider some perturbations of a family of pairwise commuting linear quantum Hamiltonians on the torus with possibly dense pure point spectra. We prove that the Rayleigh-Schrödinger perturbation series converge near each unperturbed eigenvalue under the form of a convergent quantum Birkhoff normal form. Moreover the family is jointly diagonalised by a common unitary operator explicitly constructed by a Newton type algorithm. This leads to the fact that the spectra of the family remain pure point. The results are uniform in the Planck constant near . The unperturbed frequencies satisfy a small divisors condition %(Bruno type condition (including the Diophantine case) and we explicitly estimate how this condition can be released when the family tends to the unperturbed one
Empirical Regression Method for Backward Doubly Stochastic Differential Equations
No full textInternational audienceIn this paper we design a numerical scheme for approximating Backward Doubly Stochastic Differential Equations (BDSDEs for short) which represent solution to Stochastic Partial Differential Equations (SPDEs). We first use a time-discretization and then, we decompose the value function on a functions basis. The functions are deterministic and depend only on time-space variables, while decomposition coefficients depend on the external Brownian motion B. The coefficients are evaluated through a empirical regression scheme, which is performed conditionally to B. We establish non asymptotic error estimates, conditionally to B, and deduce how to tune parameters to obtain a convergence conditionally and unconditionally to B. We provide numerical experiments as well
On the lexicographic degree of two-bridge knots
No full text14p., 21 figsInternational audienceWe study the degree of polynomial representations of knots. We obtain the lexicographic degree for two-bridge torus knots and generalized twist knots. The proof uses the braid theoretical method developed by Orevkov to study real plane curves, combined with previous results from [KP10] and [BKP14]. We also give a sharp lower bound for the lexicographic degree of any knot, using real polynomial curves properties
IASI is turning ten !
No full textInternational audienceThe IASI mission is a versatile mission that fulfills the needs of three different communities: numerical weather prediction, climate research and atmospheric composition monitoring. In order to converge on the design of such an instrument all three communities had to make “reasonable accommodations” 20 years ago, and it turns out that this mission is now recognized as essential for weather forecasting, and for tracking pollutants/greenhouse gases from space. With the launch of MetOp-B and -C and the continuity and new challenges offered by IASI-NG, an exceptional data record will be available in the next few years.The presentation (movie) illustrates some of the major findings related to atmospheric composition changes as monitored by IASI during the last 10 years. It relies on accurate data available in near real time along with an excellent horizontal coverage. We will show the global scale mapping of gases, along with the detection of dust and ash particles, as well as the potential of the mission to catch special events such as volcanic eruptions, large fires and pollution peaks
Using statistical models to explore ensemble uncertainty in climate impact studies: the example of air pollution in Europe
No full textInternational audienceBecause of its sensitivity to unfavorable weather patterns, air pollution is sensitive to climate change so that, in the future, a climate penalty could jeopardize the expected efficiency of air pollution mitigation measures. A common method to assess the impact of climate on air quality consists in implementing chemistry-transport models forced by climate projections. However, the computing cost of such methods requires optimizing ensemble exploration techniques. By using a training data set from a deterministic projection of climate and air quality over Europe, we identified the main meteorological drivers of air quality for eight regions in Europe and developed statistical models that could be used to predict air pollutant concentrations. The evolution of the key climate variables driving either particulate or gaseous pollution allows selecting the members of the EuroCordex ensemble of regional climate projections that should be used in priority for future air quality projections (CanESM2/RCA4; CNRM-CM5-LR/RCA4 and CSIRO-Mk3-6-0/RCA4 and MPI-ESM-LR/CCLM following the EuroCordex terminology). After having tested the validity of the statistical model in predictive mode, we can provide ranges of uncertainty attributed to the spread of the regional climate projection ensemble by the end of the century (2071–2100) for the RCP8.5. In the three regions where the statistical model of the impact of climate change on PM 2.5 offers satisfactory performances , we find a climate benefit (a decrease of PM 2.5 concentrations under future climate) of −1.08 (±0.21), −1.03 (±0.32), −0.83 (±0.14) µg m −3 , for respectively Eastern Eu-rope, Mid-Europe and Northern Italy. In the British-Irish Isles, Scandinavia, France, the Iberian Peninsula and the Mediterranean, the statistical model is not considered skillful enough to draw any conclusion for PM 2.5. In Eastern Europe, France, the Iberian Peninsula, Mid-Europe and Northern Italy, the statistical model of the impact of climate change on ozone was considered satisfactory and it confirms the climate penalty bearing upon ozone of 10.51 (±3.06), 11.70 (±3.63), 11.53 (±1.55), 9.86 (±4.41), 4.82 (±1.79) µg m −3 , respectively. In the British-Irish Isles, Scandinavia and the Mediterranean, the skill of the statistical model was not considered robust enough to draw any conclusion for ozone pollution
Atmospheric composition: IASI’s top ten
No full textInternational audienceThe IASI mission is a versatile mission that fulfills the needs of three different communities:numerical weather prediction, climate research and atmospheric composition monitoring. In order toconverge on the design of such an instrument all three communities had to make reasonableaccommodations 20 years ago, and it turns out that this mission is now recognized as essential forweather forecasting, and for tracking pollutants/greenhouse gases from space. With the launch ofMetOp-B and -C and the continuity and new challenges offered by IASI-NG, an exceptional datarecord will be available in the next few years.The presentation (movie) illustrates some of the major findings related to atmospheric compositionchanges as monitored by IASI during the last 10 years. It relies on accurate data available in near realtime along with an excellent horizontal coverage. We will show the global scale mapping of gases,along with the detection of dust and ash particles, as well as the potential of the mission to catchspecial events such as volcanic eruptions, large fires and pollution peaks
Resistive Plate Chamber Digitization in a Hadronic Shower Environment
No full textInternational audienceThe CALICE Semi-Digital Hadron Calorimeter (SDHCAL) technological prototype is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a three-threshold readout as the active medium. This technology is one of the two options proposed for the hadron calorimeter of the International Large Detector for the International Linear Collider. The prototype was exposed to beams of muons, electrons and pions of different energies at the CERN Super Proton Synchrotron. To be able to study the performance of such a calorimeter in future experiments it is important to ensure reliable simulation of its response. In this paper we present our prototype simulation performed with GEANT4 and the digitization procedure achieved with an algorithm called SimDigital. A detailed description of this algorithm is given and the methods to determinate its parameters using muon tracks and electromagnetic showers are explained. The comparison with hadronic shower data shows a good agreement up to 50 GeV. Discrepancies are observed at higher energies. The reasons for these differences are investigated
Solvation of Palladium Clusters in an Ionic Liquid: A QM/MM Molecular Dynamics Study
No full textInternational audienc
The effects of input tariffs on productivity: panel data evidence for OECD countries
No full textInternational audienceBased on a panel of 16 OECD countries and 10 manufacturing industries over 1996–2007, this paper investigates the impact of tariffs on foreign intermediate goods on productivity growth in downstream manufacturing industries. The results show that imposing tariffs on imported intermediate goods is particularly harmful for industries that operate close to the global technological frontier. We also consider the possibility that input-tariff liberalisation may have different effects depending on the technological content of imported intermediate goods. Our findings suggest that protecting imports of high-technological goods is more harmful for productivity improvements in industries that operate close to global best practice