59270303
High Accuracy 233U(n, f) Cross-Section Measurement at the White-Neutron Source n_TOF from Near-Thermal to 1 MeV Neutron Energy
The U-233(n, f) cross section has been measured at the white neutron source n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from similar to 30 meV to 1 MeV neutron energy. The U-233(n, f) cross section has been determined relative to a reference sample of U-235(n, f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n_TOF installation result in an accuracy around 3 range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross section by means of R-matrix analysis over a wide energy range. The results are, in general, in good agreement with the most recent high-accuracy measurement of this fission cross section, over the more limited range of the previous measurements, and indicated that even the latest evaluations underestimate the cross section in the epithermal region. The present high-quality data provide the basis for a more precise evaluation of the U-233 fission cross section and for improving the reliability of databases needed for the design of new energy systems based on the Th/U cycle.
1115406
Spin formalism in the algebraic scattering theory for heavy ions.
We develop a simple method of treating spin effects in the frame of algebraic scattering theory and apply it to the system {sup 16}O+{sup 65}Cu at {ital E}{sub c.m.}=44.77 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.
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.
42512324
Charge-Changing Interaction of Ultrarelativistic Pb Nuclei
We present experimental results of nuclear-charge changing interactions for 158A-GeV ultrarelativistic In ions in Si, Ge, Sn, W, and Pb targets. Calculations based on the abrasion-ablation model for hadronic interaction and the RELDIS model for electromagnetic dissociation are compared to the data.
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.
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
116941153
Beyond Standard Model and Exotics: Experimental overview
120940806
The muon high level trigger of the ATLAS experiment
The ATLAS experiment at CERN's Large Hadron Collider (LHC) has been designed and built for new discoveries in High Energy Physics as well as for precision measurements of Standard Model parameters. To satisfy the limited data acquisition and recording capability, at the LHC project luminosity, the ATLAS trigger system must select a very small rate of physically interesting events (~200 Hz) among about 40 million events per second. In the case of events containing muons, as described in this work, the first hardware-based level (Level-1) starts from coincidence of hits in the Muon Spectrometer trigger chambers to select Regions of Interest (RoI) where muons produce significant activity. Such RoIs are used as seeds for the two subsequent trigger levels (Level-2 and Event Filter), running on dedicated online farms, which constitute the High Level Trigger (HLT). This seeding strategy is crucial to drastically reduce the total processing time. Within the Muon HLT, few algorithms are implemented in different steps according to predefined sequences of Feature Extraction (FEX) and Hypothesis (HYPO) algorithms, whose goal is to validate the previously selected muon objects. The ATLAS muon trigger system, thanks to its particular design and to the peculiar structure of the Muon Spectrometer, is able to provide muon stand-alone event trigger decisions, that can be furtherly refined by exploiting the muon information coming from the other ATLAS subdetectors. Muon HLT algorithms are described here in terms of working functionality and performance both on simulated and real data, including non-standard trigger configurations (like cosmic data and LHC start-up scenarios).
123468882
Prospects for SUSY discovery based on inclusive searches with the ATLAS detector
The search for Supersymmetry (SUSY) among the possible scenarios of new physics is one of the most relevant goals of the ATLAS experiment running at CERN's Large Hadron Collider. In the present work the expected prospects for discovering SUSY with the ATLAS detector are reviewed, in particular for the first fb-1 of collected integrated luminosity. All studies and results reported here are based on inclusive search analyses realized with Monte Carlo signal and background data simulated through the ATLAS apparatus.