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Greynat, D., de Rafael, E., & Vulvert, G. (2014). Asymptotic behaviour of pion-pion total cross-sections. J. High Energy Phys., 03(3), 107–21pp.
Abstract: We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the pi pi total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log(2)s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for pi(+)pi(-), pi(+/-)pi(0) and pi(0)pi(0) scattering within the framework of the constituent chiral quark model (C chi QM) in the limit of a large number of colours N-c and discuss their asymptotic behaviours. The same pi pi cross sections are also discussed within the general framework of Large-N-c QCD and we show that it is possible to make an Ansatz for the isospin I = 1 and I = 0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N-c counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the sigma(total)(pi +/-pi 0)(s) cross section predicted by the CxQM with the high energy behaviour predicted by the Large-N-c Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp scattering total cross sections.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Standalone vertex finding in the ATLAS muon spectrometer. J. Instrum., 9, P02001–39pp.
Abstract: A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to b (b) over bar final states, and pp collision data at root s = 7 TeV collected with the ATLAS detector at the LHC during 2011.
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Gonzalez-Sevilla, S. et al, Bernabeu Verdú, J., Civera, J. V., Garcia, C., Lacasta, C., Marco, R., et al. (2014). A double-sided silicon micro-strip Super-Module for the ATLAS Inner Detector upgrade in the High-Luminosity LHC. J. Instrum., 9, P02003–37pp.
Abstract: The ATLAS experiment is a general purpose detector aiming to fully exploit the discovery potential of the Large Hadron Collider (LHC) at CERN. It is foreseen that after several years of successful data-taking, the LHC physics programme will be extended in the so-called High-Luminosity LHC, where the instantaneous luminosity will be increased up to 5 x 10(34) cm(-2) s(-1). For ATLAS, an upgrade scenario will imply the complete replacement of its internal tracker, as the existing detector will not provide the required performance due to the cumulated radiation damage and the increase in the detector occupancy. The current baseline layout for the new ATLAS tracker is an all-silicon-based detector, with pixel sensors in the inner layers and silicon micro-strip detectors at intermediate and outer radii. The super-module is an integration concept proposed for the strip region of the future ATLAS tracker, where double-sided stereo silicon micro-strip modules are assembled into a low-mass local support structure. An electrical super-module prototype for eight double-sided strip modules has been constructed. The aim is to exercise the multi-module readout chain and to investigate the noise performance of such a system. In this paper, the main components of the current super-module prototype are described and its electrical performance is presented in detail.
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Pastore, A., Davesne, D., & Navarro, J. (2014). Nuclear matter response function with a central plus tensor Landau interaction. J. Phys. G, 41(5), 055103–17pp.
Abstract: We present a method to obtain response functions in the random phase approximation (RPA) based on a residual interaction described in terms of Landau parameters with central plus tensor contributions. The response functions keep the explicit momentum dependence of the RPA, in contrast with the traditional Landau approximation. Results for symmetric nuclear matter and pure neutron matter are presented using Landau parameters derived from finite-range interactions, both phenomenological and microscopic. We study the convergence of response functions as the number of Landau parameters is increased.
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Koolen, B. B., Vidal-Sicart, S., Benlloch, J. M., & Olmos, R. A. V. (2014). Evaluating heterogeneity of primary tumor 18 F-FDG uptake in breast cancer with a dedicated breast PET ( MAMMI): a feasibility study based on correlation with PET/CT. Nucl. Med. Commun., 35(5), 446–452.
Abstract: PurposeThe aim of the study was to evaluate the heterogeneity of primary tumor F-18-fluorodeoxyglucose (F-18-FDG) uptake in breast cancer patients using a dedicated breast PET.Patients and methodsA positron emission tomography/computed tomography (PET/CT) of the thorax was performed 60 min after administration of 180-240 MBq of F-18-FDG in patients with breast cancer. Subsequently, 110 min after injection, a scan was taken with a dedicated high-resolution breast PET [MAMmography with Molecular Imaging (MAMMI)]. Both procedures were performed with the patients in the prone position. Four-point scores were used to compare the intensity (0: none; 1: mild; 2: moderate; 3: high) and heterogeneity (0: none; 1: mild; 2: moderate; 3: high) of F-18-FDG uptake between PET/CT and MAMMI images.ResultsThirty-five patients in whom the primary tumor was visualized on both scans were included in this analysis. The mean primary tumor size was 35.1 mm (range 10-108 mm). The mean intensity score was similar on both devices (2.4 for PET/CT and 2.3 for MAMMI; P=0.439), but the mean heterogeneity score on MAMMI images was significantly higher (PET/CT 1.9 vs. MAMMI 2.3; P=0.005). MAMMI showed a higher heterogeneity score in 11 (31%) of 35 patients, especially in tumors with moderate or high intensity. Significantly higher heterogeneity scores on both PET/CT and MAMMI were seen in large tumors (P=0.005 and 0.014, respectively) and in tumors with high intensity scores (P=0.012 and P<0.001, respectively).ConclusionHeterogeneous tumor F-18-FDG uptake in breast cancer is frequently observed, particularly in large tumors with intense F-18-FDG uptake. It is more often seen on MAMMI PET than on conventional PET/CT. Although the observed heterogeneity should be proven histopathologically, this finding offers a rationale for F-18-FDG-guided biopsies.
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