8021426
Parity violating elastic electron scattering and neutron density distributions in the relativistic Hartree-Bogoliubov model
Parity-violating elastic electron scattering on neutron-rich nuclei is described in the framework of relativistic mean-field theory. Self-consistent g
120041897
Level densities of transitional Sm nuclei
Experimentally determined level densities of the transitional isotopes $^{148,149,150,152}\mathrm{Sm}$ at excitation energies below and around the neutron binding energy are compared with microcanonical calculations based on a Monte Carlo approach to noncollective level densities, folded with a collective enhancement estimated in the frame of the interacting boson model (IBM). The IBM parameters are adjusted so as to reproduce the low-lying discrete levels of both parities, with the exception of the odd-mass nucleus, $^{149}\mathrm{Sm}$, where complete decoupling of the unpaired neutron from the core is assumed.
117846326
The Zr-92(n,gamma) reaction and its implications for stellar nucleosynthesis
Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the Zr-92(n,gamma) cross section has been remeasured at the CERN n_TOF facility, providing a set of improved parameters for 44 resonances in the neutron energy range up to 40 keV. With this information the cross-section uncertainties in the keV region could be reduced to 5% as required for s-process nucleosynthesis studies and technological applications.
2076925
PT symmetry breaking and explicit expressions for the pseudo-norm in the Scarf II potential
Closed expressions are derived for the pseudo-norm, norm and orthogonality relations for arbitrary bound states of the PT symmetric and the Hermitian Scarf II potential for the first time. The pseudo-norm is found to have indefinite sign in general. Some aspects of the spontaneous breakdown of PT symmetry are analyzed.
98058986
Measurement of the neutron induced fission cross section on transuranic (TRU) elements at the n_TOF facility at CERN
During the 2004 campaign, the n_TOF collaboration measured neutron fission cross sections for ^{233}U, ^{241,243}Am, ^{245}Cm, as well as the fission standards ^{235,238}U, using a sealed Fission Ionization Chamber (FIC). The setup included a total of 16 targets and 18 electrodes mounted together in a 50-cm length chamber, allowing the measurements of all isotopes at the same time, thus in the same experimental conditions. A brief description of the facility and of the detector setup will be presented followed by the preliminary results of the analysis of ^{235}U, ^{233}U, and ^{245}Cm from thermal energies up to some tenths of MeV.
118535533
New description of the doublet bands in doubly odd nuclei
The experimentally observed {delta}I=1 doublet bands in some odd-odd nuclei are analyzed within the orthosymplectic extension of the interacting vector boson model (IVBM). A new, purely collective interpretation of these bands is given on the basis of the obtained boson-fermion dynamical symmetry of the model. It is illustrated by its application to three odd-odd nuclei from the A{approx}130 region, namely {sup 126}Pr, {sup 134}Pr, and {sup 132}La. The theoretical predictions for the energy levels of the doublet bands as well as E2 and M1 transition probabilities between the states of the yrast band in the last two nuclei are compared with experiment and the results of other theoretical approaches. The obtained results reveal the applicability of the orthosymplectic extension of the IVBM.
51843235
The ATLAS Data Acquisition and Trigger: concept, design and status
This article presents the base-line design and implementation of the ATLAS Trigger and Data Acquisition system, in particular the Data Flow and High Level Trigger components. The status of the installation and commissioning of the system is also presented.
122706822
Neutralino spin measurement with ATLAS
One of the goals of the ATLAS experiment at the LHC is to search for evidence of Supersymmetry (SUSY) signals and to measure, if discovered, the main properties of the new particles, like the spin. Left-handed squark cascade decay to second lightest neutralino (~ 0 ) which further decays to slepton represents a good opportunity for SUSY particles’ spin measurement. The observability of charge asymmetries in invariant mass distributions of some final products is investigated to prove that neutralino spin is 1/2. The criteria used to select signal events and to reject background are described, together with the applied cut efficiencies. Results on charge asymmetry are then shown and discussed.
53139097
Implementation and performance of the ATLAS trigger muon "vertical slice"
The ATLAS (A Toroidal LHC ApparatuS) trigger system is designed to keep high effiency for interesting events while achieving a rejection of low transverse momentum ( p T ) physics of about 10 7 , thus reaching the ∼200 Hz data storage capability of the Data Aquisition system. A three levels structure has been implemented for this purpose, as described in this work for the case of the muon trigger system. After describing the implementation, some performance results are presented in terms of final trigger rates, resolutions, efficiencies, background rejection and algorithm latency.
124822108
MUON RECONSTRUCTION AND IDENTIFICATION FOR THE EVENT FILTER OF THE ATLAS EXPERIMENT
22148204
Implementation and performance of the third level muon trigger of the ATLAS experiment at LHC
The trigger system of the ATLAS experiment at the LHC aims at a high selectivity in order to keep the full physics potential while reducing the 40 MHz initial event rate imposed by the LHC bunch crossing down to /spl sim/100 Hz, as required by the data acquisition system. Algorithms working in the final stage of the trigger environment (Event Filter) are implemented to run both in a "wrapped" mode (reconstructing tracks in the entire Muon Spectrometer) and in a "seeded" mode (according to a dedicated strategy that performs pattern recognition only in regions of the detector where trigger hypotheses have been produced at earlier stages). The working principles of the offline muon reconstruction and identification algorithms (MOORE and MuId) implemented and used in the framework of the Event Filter are discussed in this paper. The reconstruction performance of these algorithms is presented for both modes in terms of efficiency, momentum resolution, rejection power and execution times on several samples of simulated single muon events, also taking into account the high background environment expected for ATLAS.