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.
124822108
MUON RECONSTRUCTION AND IDENTIFICATION FOR THE EVENT FILTER OF THE ATLAS EXPERIMENT
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.
17810666
ATLAS RPC Cosmic Ray Teststand at INFN Lecce
We describe the design and functionality of the cosmic ray teststand built at 
INFN Lecce for ATLAS RPC quality control assurance.
6222401
Implementation and performance of the seeded reconstruction for the ATLAS event filter
ATLAS is one of the four major Large Hadron Collider (LHC) experiments that will start data taking in 2007. It is designed to cover a wide range of physics topics. The ATLAS trigger system has to be able to reduce an initial 40 MHz event rate, corresponding to an average of 23 proton-proton inelastic interactions per every 25 ns bunch crossing, to 200 Hz admissible by the Data Acquisition System. The ATLAS trigger is divided in three different levels. The first one provides a signal describing an event signature using dedicated custom hardware. This signature must be confirmed by the High Level Trigger (HLT) which using commercial computing farms performs an event reconstruction by running a sequence of algorithms. The validity of a signature is checked after every algorithm execution. A main characteristic of the ATLAS HLT is that only the data in a certain window around the position flagged by the first level trigger are analyzed. In this work, the performance of one sequence that runs at the Event Filter level (third level) is demonstrated. The goal of this sequence is to reconstruct and identify high transverse momentum electrons by performing cluster reconstruction at the electromagnetic calorimeter, track reconstruction at the Inner Detector, and cluster track matching.
117068975
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. 
Since July 2004, about 270 RPC units has been certified at INFN Lecce site and delivered to CERN, for being integrated in the final muon station of the ATLAS barrel region. 
We show the key RPC characteristics which qualify the performance of this detector technology as muon trigger chamber in the harsh LHC enviroments. 
These are dark current, chamber efficiency, noise rate, gas volume tomography, and gas leakage.
33472567
Measurement of the Sm-151(n, gamma) cross section from 0.6-eV to 1-MeV via the neutron time-of-flight technique at the CERN n_TOF facility
The {sup 151}Sm(n,{gamma}) cross section was measured with the time-of-flight technique from 0.6 eV up to 1 MeV relative to the Au standard with an overall uncertainty of typically 6%. Neutrons were produced by spallation at the innovative n{sub T}OF facility at CERN; the {gamma} rays from capture events were detected with organic C{sub 6}D{sub 6} scintillators. Experimental setup and data analysis procedures are described with emphasis on the corrections for detection efficiency, background subtraction, and neutron flux determination. At low energies, resonances could be resolved up to about 1 keV, yielding a resonance integral of 3575{+-}210 b, an average s-wave resonance spacing of =1.49{+-}0.07 eV, and a neutron strength function of =(3.87{+-}0.33)x10{sup -4}. Maxwellian-averaged capture cross sections are reported for thermal energies between 5 and 100 keV. These results are of relevance for nuclear structure studies, nuclear astrophysics, and nuclear technology. The new value of the Maxwellian-averaged cross section at kT=30 keV is 3.08{+-}0.15 b, considerably larger than previous theoretical estimates, and provides better constraints for the thermodynamic conditions during the occurrence of the slow neutron capture process in low-mass stars during their asymptotic giant branch phase.
21048421
Electromagnetically induced nuclear-charge pickup observed in ultrarelativistic Pb collisions.
A strong increase of inclusive nuclear-charge pickup cross sections, forming 83Bi from 158A GeV 82Pb ions, is observed in comparison to similar measurements at 10.6A GeV. From the dependence of these cross sections on target atomic number, this increase is attributed to the electromagnetic process of pion production by equivalent photons. The observed cross sections can be reproduced quantitatively using the recently developed RELDIS code.
121284029
The measurement of the Pb-206 (n, gamma) cross section and stellar implications
The neutron capture cross section of 206Pb has been measured at the CERN n\TOF spectrometer using a setup of two C6D6 detectors. In the energy interval from 1 eV to 600 keV the cross section is dominated by resonances, which were analyzed via the R-matrix analysis code SAMMY. In the relevant energy ranges for stellar nucleosynthesis, i.e., at thermal energies of kT = 8 keV and kT = 23 keV, the present Maxwellian average cross section differs by 20% and 9% from the recommended values of Bao et al respectively. From the new cross section the s-abundance of 206Pb could be reliably determined as 70(4)%. This result is of importance in order to test and constrain r-process abundance calculations in the actinide region, because the r-process portion of 206Pb is dominated by α-back decays of short-lived transbismuth isotopes.
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.
73657613
Spectroscopy near the proton drip line in the deformed A=130 mass region : the Pr-126 nucleus
The near proton drip line nucleus Pr-126 was studied via in-beam gamma-ray spectroscopy using the Ca-40 + Mo-92 reaction at 190 MeV. We observed for t