Search results for "Jet"
showing 10 items of 4711 documents
Structure, tritium depth profile and desorption from 'plasma-facing' beryllium materials of ITER-Like-Wall at JET
2017
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053 . The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Top quark mass measurement in the lepton plus jets channel using a modified matrix element method
2008
We report a measurement of the top quark mass, m(t), obtained from p(p)over bar collisions at root s=1.96 TeV at the Fermilab Tevatron using the CDF II detector. We analyze a sample corresponding to an integrated luminosity of 1.9 fb(-1). We select events with an electron or muon, large missing transverse energy, and exactly four high-energy jets in the central region of the detector, at least one of which is tagged as coming from a b quark. We calculate a signal likelihood using a matrix element integration method, where the matrix element is modified by using effective propagators to take into account assumptions on event kinematics. Our event likelihood is a function of m(t) and a parame…
Search for right-handed W bosons in top quark decay
2005
We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of $t\bar{t}$ events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb^-1, collected by the DO detector at the Fermilab Tevatron $p\bar{p}$ Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the $t\bar{t}$ and decay products, which allows for the measurement of the leptonic decay angle $\theta^*$ for each event. By comparing the $\cos\theta^*$ distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00+-0.13(stat)+-0.07(syst). This …
A search for time dependent neutrino emission from microquasars with the ANTARES telescope
2014
[EN] Results are presented on a search for neutrino emission from a sample of six microquasars, based on the data collected by the ANTARES neutrino telescope between 2007 and 2010. By means of appropriate time cuts, the neutrino search has been restricted to the periods when the acceleration of relativistic jets was taking place at the microquasars under study. The time cuts have been chosen using the information from the X-ray telescopes RXTE/ASM and Swift/BAT, and, in one case, the gamma-ray telescope Fermi/LAT. No statistically significant excess has been observed, thus upper limits on the neutrino fluences have been derived and compared to the predictions by models. Constraints have bee…
Evolution of the longitudinal and azimuthal structure of the near-side jet peak in Pb-Pb collisions at √sNN = 2.76 TeV
2017
In two-particle angular correlation measurements, jets give rise to a near-side peak, formed by particles associated to a higher-pT trigger particle. Measurements of these correlations as a function of pseudorapidity (η) and azimuthal (ϕ) differences are used to extract the centrality and pT dependence of the shape of the near-side peak in the pT range 1 < pT < 8 GeV/c in Pb-Pb and pp collisions at √sNN = 2.76 TeV. A combined fit of the near-side peak and long-range correlations is applied to the data and the peak shape is quantified by the variance of the distributions. While the width of the peak in the ϕ direction is almost independent of centrality, a significant broadening in the η dir…
First Offline Results from the S3 Low-Energy Branch
2022
International audience; We present the first results obtained from the S3 Low-Energy Branch , the gas cell setup at SPIRAL2-GANIL, which will be installed behind the S3 spectrometer for atomic and nuclear spectroscopy studies of exotic nuclei. The installation is currently being commissioned offline, with the aim to establish optimum conditions for the operation of the radio frequency quadrupole ion guides, mass separation and ion bunching, providing high-efficiency and low-energy spatial spread for the isotopes of interest. Transmission and mass-resolving power measurements are presented for the different components of the S3-LEB setup. In addition, a single-longitudinal-mode, injection-lo…
Measuring the isotope effect on the gross beryllium erosion in JET
2022
Abstract The isotope effect, hydrogen (H) versus deuterium (D), on the gross beryllium (Be) erosion yield has been measured in ohmic limiter plasmas in JET tokamak by spectroscopic means. A simplified method to extract the effective sputtering yield from the quotient of the radiances of the D α or D γ and the Be II lines at 527 nm was applied. A clear isotope effect has been found, the erosion yield of D being about a factor of 2 larger compared to H in the whole explored plasma density range. This is in agreement with physical sputtering data obtained with H+ and D+ ion beams and also with material surface computer simulations. The already published contribution of chemically assisted phys…
The laser and optical system for the RIBF-PALIS experiment
2017
Abstract This paper describes the laser and optical system for the Parasitic radioactive isotope (RI) beam production by Laser Ion-Source (PALIS) in the RIKEN fragment separator facility. This system requires an optical path length of 70 m for transporting the laser beam from the laser light source to the place for resonance ionization. To accomplish this, we designed and implemented a simple optical system consisting of several mirrors equipped with compact stepping motor actuators, lenses, beam spot screens and network cameras. The system enables multi-step laser resonance ionization in the gas cell and gas jet via overlap with a diameter of a few millimeters, between the laser photons an…
Helium-jet transportation of recoil atoms into a liquid phase
1973
Abstract A rapid inexpensive method has been developed for transportation of recoiling short-lived radioactive nuclides from a target chamber over distances of several meters into a liquid phase. This allows rapid radiochemical separation of different elements. The carrier-loaded helium-jet transport technique is employed without a pumping system. The method would appear to be applicable to most chemical elements. The transport efficiency is higher than 50% and the transport time can be made much shorter than 1 s. Radiochemical separation times of a few seconds were achieved.
Transport efficiency of the helium-jet recoil-transport method with pure helium
1973
Abstract New techniques have been developed for measuring the transport efficiency of the helium-jet recoil-transport method in the transport of radioactive recoil atoms. The dependence of the transport efficiency on main equipment parameters was studied experimentally using pure commercial-grade helium. The results are given in terms of helium mass throughput, capillary parameters and location of a catcher foil. High to moderate efficiencies were observed at transport distances shorter than 20 cm. Efficiencies obtained with pure helium at distances longer than 1 m are low, typically less than 1%. Possibilities for further development of the method are briefly discussed.