http://www.infn.it/pubblicazioni it-IT INFN - Dataweb 105,252302 (2010)

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at root s(NN) p = 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (vertical bar eta vertical bar < 0.8) and transverse momentum range 0.2 < p(t) < 5.0 GeV/c. The elliptic flow signal v(2), measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 +/- 0.002(stat) +/- 0.003(syst) in the 40%-50% centrality class. The differential elliptic flow v(2)(p(t)) reaches a maximum of 0.2 near p(t) = 3 GeV/c. Compared to RHIC Au-Au collisions at root s(NN) = 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.]]> Fri, 10 Feb 2012 17:40:08 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000286750400008 21, (2011)

Purpose - The purpose of this paper is to present numerical results about phase separation of binary fluid mixtures quenched by contact with cold walls.Design/methodology/approach - The thermal phase separation is simulated by using a hybrid lattice Boltzmann method that solves the continuity and the Navier-Stokes equations. The equations for energy and concentration are solved by using a finite-difference scheme. This approach provides a complete description of the thermo-hydrodynamic effects in the mixture.Findings - A rich variety of domain patterns are found depending on the viscosity and on the heat conductivity of the mixture. Ordered lamellar structures are observed at high viscosity while domains rounded in shape dominate the phase separation at low viscosity, where two scales characterize the growth of domains.Research limitations/implications - The present approach provides a numerical method that can be extended to other systems such as liquid-vapor or lamellar systems. Moreover, a three-dimensional study can give a complete picture of thermo-hydrodynamic effects.Originality/value - This paper provides a consistent thermodynamic theoretical framework for a binary fluid mixture and a numerically stable method to simulate them.]]> Fri, 10 Feb 2012 16:53:09 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000293312100006 29, (2006)

The definition of a sphere depends on the definition of distance in the embedding three-dimensional space; the classification is straightforward, but should be clearly understood to appreciate the richness and the variety of this concept in geometry and mathematical physics. There are essentially three loci of points with the same "distance" from a centre O: the ordinary sphere S-2, the single-sheet hyperboloid AdS(2) and the two-sheet hyperboloid H. The extraordinary fertility of AdS2 and H began in the XIX century, when the Italian mathematician E. Beltrami discovered an intrinsic metric on a disk on the plane which is a canonical realization of two-dimensional hyperbolic geometry with constant curvature, but did not recognize that it is just a stereographic projection of H. Subsequently, AdS2 became an important geometrical building block in special relativity, in cosmology and, in 1959, in a solution of Einstein-Maxwell's field equations corresponding to a uniform electromagnetic field. This space-time, here called BR after Bertotti and Robinson's papers of 1959, consists in the combination of two (generalized) spheres and can be obtained in a purely geometric way. The 1311 geometry has played a relevant role in the search for new unifying fundamental laws, in particular in very high-energy physics, and has provided examples to test and exemplify new physical principles. In sect. 4 we briefly outline three general areas. The first area is the extension of a classical field theory to the complex domain (in particular, in relation to quantum gravity). Ideally, the most interesting complexification of a Riemannian manifold consists in endowing it with a Kahlerian structure; it turns out that, while this is possible for a definite signature in many cases, in space-time a Kahlerian manifold is obtained only if it is just the BR solution (or, trivially, if it is flat). The other two areas are: the exploration of the quantum properties of the horizon of a black hole and the holographic principle; string theory, and the fundamental role of a scalar field, the dilaton. We give, and clarify, examples in which the BR solution has been applied.]]> Fri, 10 Feb 2012 15:33:47 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000242116700001 743,L20 (2011)

The angular momentum transfer associated with Vela-like glitches has never been calculated directly within a realistic scenario for the storage and release of superfluid vorticity; therefore, the explanation of giant glitches in terms of vortices has not yet been tested against observations. We present the first physically reasonable model, both at the microscopic and macroscopic level (spherical geometry, n = 1 polytropic density profile, density-dependent pinning forces compatible with vortex rigidity), to determine where in the star the vorticity is pinned, how much of it is pinned, and for how long. For standard neutron star parameters (M = 1.4 M(circle dot), R(s) = 10 km, (Omega) over dot = (Omega) over dot(Vela) = -10(-10) Hz s(-1)), we find that maximum pinning forces of order f(m) approximate to 10(15) dyn cm(-1) can accumulate Delta L(gl) approximate to 10(40) erg s of superfluid angular momentum, and release it to the crust at intervals Delta t(gl) approximate to 3 years. This estimate of Delta L(gl) is one order of magnitude smaller than that implied indirectly by current models for post-glitch recovery, where the core and inner-crust vortices are taken as physically disconnected; yet, it successfully yields the magnitudes observed in recent Vela glitches for both jump parameters, Delta O(gl) and Delta(Omega) over dot(gl), provided one assumes that only a small fraction (<10%) of the total star vorticity is coupled to the crust on the short timescale of a glitch. This is reasonable in our approach, where no layer of normal matter exists between the core and the inner-crust, as indicated by existing microscopic calculation. The new scenario presented here is nonetheless compatible with current post-glitch models.]]> Fri, 10 Feb 2012 14:23:21 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000297372600020 47, (2000)

CHIMERA is a second generation 4 pi detector for high resolution light particle and fragment measurements in the field of intermediate energy nuclear reactions. An enhanced data acquisition, control and trigger system has been developed to manage the almost 5000 electronic channels of the detector. The data acquisition system is based on a Fast Data Link (FDL) connection between 9U VME crates. The FDL is a highly programmable VME device. It performs data readout and transfer to a destination VME CPU, the FIC8243, running the real time OS9 operating system. Data read and transfer is performed by a fast protocol (Sparse Data Scan) whose performances have been improved introducing the Chained Block Transfer mode (CBLT) technique. Data collected by the CPU are broadcast to analysis work-stations for on-line data analysis and storage. All commands from and to the VME CPU are sent by socket-based network protocols. Complete remote control of the electronic front-end is obtained by a system of client-server applications. A first level event selection and control during readout is made by a trigger system based on a new VME 9U board (MUSE), fully integrated with the FDL readout system.]]> Fri, 10 Feb 2012 11:26:08 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000087474200015 85,014313 (2012)

An equation of motion method for solving the nuclear eigenvalue problem in a basis of microscopic multiphonon states is reformulated consistently in terms of Tamm-Dancoff phonons. The potential and limits of the method are illustrated through the calculation of the nuclear response to dipole and quadrupole external fields in (16)O. The calculation is performed using either a Nilsson or a Hartree-Fock basis. The role of the multiphonon states is shown to depend strongly on the choice of the basis. The effect of the truncation of the three-phonon subspace is also discussed.]]> Thu, 09 Feb 2012 19:53:10 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000299291400005 583, (2004)

Bose-Einstein correlations in one and two dimensions have been studied in deep inelastic ep scattering events measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb(-1). The correlations are independent of the virtuality of the exchanged photon, Q(2), in the range 0.1 < Q(2) < 8000 GeV(2). There is no significant difference between the correlations in the current and target regions of the Breit frame for Q(2) > 100 GeV(2). The two-dimensional shape of the particle-production source was investigated, and a significant difference between the transverse and the longitudinal dimensions of the source is observed. This difference also shows no Q(2) dependence. The results demonstrate that Bose-Einstein interference, and hence the size of the particle-production source, is insensitive to the hard subprocess. (C) 2004 Published by Elsevier B.V.]]> Thu, 09 Feb 2012 19:05:01 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000220003900003 595, (2004)

First measurements of cross sections for isolated prompt photon production in deep inelastic ep scattering have been made using the ZEUS detector at the HERA electron-proton collider using an integrated luminosity of 121 pb(-1). A signal for isolated photons in the transverse energy and rapidity ranges 5 < E(T)(y) < 10 GeV and -0.7 < eta(gamma) < 0.9 was observed for virtualities of T the exchanged photon of Q(2) > 35 GeV(2). Cross sections are presented for inclusive prompt photons and for those accompanied by a single jet in the range E(jet)(T) greater than or equal to 6 GeV and 1.5 less than or equal to eta(jet) < 1.8. Calculations at order alpha(3)alpha(s), describe the data reasonably well. (C) 2004 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 19:03:14 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000223143300013 598, (2004)

The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0degrees to 58degrees. Due to the large exposure of about 150 m(2) sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +/- 0.003(stat.) +/-0.019(syst.). (C) 2004 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 18:59:18 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000223870100003 76,064606 (2007)

Isotope temperatures from double ratios of hydrogen, helium, lithium, beryllium, and carbon isotopic yields, and excited-state temperatures from yield ratios of particle-unstable resonances in (4)He, (5)Li, and (8)Be, were determined for spectator fragmentation, following collisions of (197)Au with targets ranging from C to Au at incident energies of 600 and 1000 MeV per nucleon. A deviation of the isotopic from the excited-state temperatures is observed which coincides with the transition from residue formation to multi-fragment production, suggesting a chemical freeze-out prior to thermal freeze-out in bulk disintegrations.]]> Thu, 09 Feb 2012 18:31:19 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000251987000036 416, (2011)

We present three-dimensional (3D) resonant radiative transfer simulations of the spatial and spectral diffusion of the Ly alpha radiation from a central source in the host galaxies of high column density absorption systems at z similar to 3. The radiative transfer simulations are based on a suite of cosmological galaxy formation simulations which reproduce a wide range of observed properties of damped Ly alpha absorption systems. The Lya emission is predicted to be spatially extended up to several arcsec, and the spectral width of the Ly alpha emission is broadened to several hundred (in some case more than thousand) km s(-1). The distribution and the dynamical state of the gas in the simulated galaxies are complex, the latter with significant contributions from rotation and both in-and out-flows. The emerging Ly alpha radiation extends to gas with column densities of N(HI) similar to 10(18) cm(-2) and its spectral shape varies strongly with viewing angle. The strong dependence on the central HI column density and the HI velocity field suggests that the Ly alpha emission will also vary strongly with time on time-scales of a few dynamical times of the central region. Such variations with time should be especially pronounced at times where the host galaxy undergoes a major merger and/or starburst. Depending on the pre-dominance of in- or out-flow along a given sightline and the central column density, the spectra show prominent blue peaks, red peaks or double-peaked profiles. Both spatial distribution and spectral shape are very sensitive to details of the galactic wind implementation. Stronger galactic winds result in more spatially extended Ly alpha emission and - somewhat counterintuitively - a narrower spectral distribution.]]> Thu, 09 Feb 2012 15:41:44 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000295378100009 416, (2011)

In this work, starting from 21 months of data from the Fermi Large Area Telescope (LAT), we derive maps of the residual isotropic gamma-ray emission, a relevant fraction of which is expected to be contributed by the extragalactic diffuse gamma-ray background (EGB). We search for the auto-correlation signals in the above gamma-ray maps and for the cross-correlation signal with the angular distribution of different classes of objects that trace the large-scale structure of the Universe. We compute the angular two-point auto-correlation function of the residual Fermi-LAT maps at energies E > 1 GeV, E > 3 GeV and E > 30 GeV well above the Galactic plane and find no significant correlation signal. This is, indeed, what is expected if the EGB were contributed by BL Lacertae (BLLacs), Flat Spectrum Radio Quasars (FSRQs) or star-forming galaxies, since, in this case, the predicted signal is very weak. Then, we search for the Integrated Sachs-Wolfe (ISW) signature by cross-correlating the Fermi-LAT maps with the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) cosmic microwave background map. We find a cross-correlation consistent with zero, even though the expected signal is larger than that of the EGB auto-correlation. Finally, in an attempt to constrain the nature of the gamma-ray background, we cross-correlate the Fermi-LAT maps with the angular distributions of objects that may contribute to the EGB: quasi-stellar objects (QSOs) in the Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) catalogue, NRAO VLA Sky Survey (NVSS) galaxies, Two Micron All Sky Survey (2MASS) galaxies and Luminous Red Galaxies (LRGs) in the SDSS catalogue. The cross-correlation is always consistent with zero, in agreement with theoretical expectations, but we find (with low statistical significance) some interesting features that may indicate that some specific classes of objects contribute to the EGB. A chi(2) analysis confirms that the correlation properties of the 21-month data do not provide strong constraints of the EGB origin. However, the results suggest that the situation will significantly improve with the 5- and 10-yr Fermi-LAT data. In future, the EGB analysis will then allow placing significant constraints on the nature of the EGB and might provide, in addition, a detection of the ISW signal.]]> Thu, 09 Feb 2012 15:41:03 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000295378100049 418, (2011)

Cosmological neutrinos strongly affect the evolution of the largest structures in the Universe, i.e. galaxies and galaxy clusters. We use large box-size full hydrodynamic simulations to investigate the non-linear effects that massive neutrinos have on the spatial properties of cold dark matter (CDM) haloes. We quantify the difference with respect to the concordance CDM model of the halo mass function and of the halo two-point correlation function. We model the redshift-space distortions and compute the errors on the linear distortion parameter beta introduced if cosmological neutrinos are assumed to be massless. We find that, if not taken correctly into account and depending on the total neutrino mass M, these effects could lead to a potentially fake signature of modified gravity. Future nearly all-sky spectroscopic galaxy surveys will be able to constrain the neutrino mass if M 0.6 eV, using beta measurements alone and independently of the value of the matter power spectrum normalization s8. In combination with other cosmological probes, this will strengthen neutrino mass constraints and help breaking parameter degeneracies.]]> Thu, 09 Feb 2012 15:39:00 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000297045700058 44, (2011)

We re-consider the idea that quantum fluctuations might reflect the existence of an 'objective randomness', i.e. a basic property of the vacuum state which is independent of any experimental accuracy of the observations or limited knowledge of initial conditions. Besides being responsible for the observed quantum behavior, this might introduce a weak, residual form of 'noise' which is intrinsic to natural phenomena and could be important for the emergence of complexity at higher physical levels. By adopting Stochastic Electro Dynamics as a heuristic model, we are driven to a picture of the vacuum as a form of highly turbulent ether, which is deep-rooted into the basic foundational aspects of both quantum physics and relativity, and to search for experimental tests of this scenario. An analysis of the most precise ether-drift experiments, operating both at room temperature and in the cryogenic regime, shows that, at present, there is some ambiguity in the interpretation of the data. In fact the average amplitude of the signal has precisely the magnitude expected, in a 'Lorentzian' form of relativity, from an underlying stochastic ether and, as such, might not be a spurious instrumental effect. This puzzle, however, should be solved in a next future with the use of new cryogenically cooled optical resonators whose stability should improve by about two orders of magnitude. In these new experimental conditions, the persistence of the present amplitude would represent a clean evidence for the type of random vacuum we are envisaging. (C) 2011 Elsevier Ltd. All rights reserved.]]> Thu, 09 Feb 2012 12:59:39 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000297965400007 533, (2004)

An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700 Hz/cm(2). We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12 C/cm(2), including a safety factor of 5. (C) 2004 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000224890000021 533, (2004)

RPCs will be used as trigger detectors in the barrel region of the, Muon Spectrometer of the ATLAS experiment at LHC. The total number of RPC units to be installed is 1088, covering a total surface of about 3500 m(2). ATLAS RPCs work in avalanche mode with C2H2F4/C4H10/SF6 (94.7%/5%/0.3%) gas mixture. A cosmic ray test stand has been designed and built in Naples laboratories in order to carry out a complete test of the ATLAS RPC units. Since August 2002 about 300 units have been tested. A description of the test stand, test procedure and results are presented. (C) 2004 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000224890000040 535, (2004)

The ATLAS Muon Spectrometer (ATLAS Collaboration, ATLAS Muon Spectrometer Technical Design Report CERN/LHCC/97-22, ATLAS TDR 10, 1997.) will use dedicated detectors to trigger on muons and to identify the bunch-crossing at the appropriate rate. The Spectrometer has been designed to perform stand-alone triggering and measurement of union transverse momentum up to 1 TeV with good resolution (from 3% up to 10% at 1 TeV). The magnetic system is composed of three large superconducting air-core toroids instrumented with trigger and high-precision tracking chambers, a central part (barrel) composed of eight coils and two end-cap magnets.The high-precision tracking system is based on Monitored Drift Tube (MDT) and Cathode Strip Chambers (CSC) in the small angle-regions. The Level-1 trigger is provided by Resistive Plate Chambers (RPC) in the barrel and Thin Gap Chambers (TGC) in the end-cap. These detectors will also measure the track coordinates in the magnetic field direction (second coordinate), to complement the precision tracking provided by the MDT which only measure the track 2 coordinates in the bending direction of the magnetic field. The trigger system covers an area of 3650 M in the barrel and 2900 m(2) in the end-cap. In the barrel region three double-gap RPC stations are used, two in the middle and one in the outer MDT chamber layer. In the end-cap region one triple-gap TGC station is used, in front of the middle MDT station, and two double-gap TGC stations behind it. The mass production of both systems is under way.The systems were involved in extensive beam tests in 2002-2003, testing their compliance with LHC timing requirements using 25 ns beam bunching to emulate the LHC beam structure, aging under critical environment conditions and so on. (C) 2004 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000225580500045 518, (2004)

The trigger for the Barrel Muon Spectrometer of the ATLAS experiment at LHC will be given by means of Resistive Plate Chambers working in avalanche mode. Before being mounted on the experimental apparatus each RPC chamber will undergo detailed quality control tests. A dedicated cosmic rays test station with good tracking resolution is operational in Naples University and INFN laboratory. All working parameters of RPCs are monitored and measured. Moreover. the uniformity of the efficiency on the whole surface is measured. A brief description of the test station and results for the first 148 Units will be presented. (C) 2003 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000188961100022 51, (2004)

The Atlas Trigger System has been designed to reduce the LHC interaction rate of about 1 GHz to the foreseen storage rate of about 100 Hz. Three trigger levels are applied in order to fulfill such a requirement. A detailed simulation of the ATLAS experiment including the hardware components and the logic of the Level-1 Muon trigger in the barrel of the muon spectrometer has been performed. This simulation has been used not only to evaluate the performances of the system but also to optimize the trigger logic design. In the barrel of the union spectrometer the trigger will be given by means of resistive plate chambers (RPCs) working in avalanche mode. Before being mounted on the experiment, accurate quality tests with cosmic rays are carried out on each RPC chamber using the test station facility of the INFN and University laboratory of Napoli. All working parameters are measured and the uniformity of the efficiency on the whole RPC surface is required. A summary of the Napoli cosmic rays tests, together with a brief description of the Atlas Trigger, in particular of the Level-1 Muon Trigger in the barrel, and the results of the trigger simulation will be given.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000223391600047 53, (2006)

In order to ensure that the resistive plate chambers used in the ATLAS experiment will not show, during their operation, any abnormal aging effect which could degrade their performances, an aging test is being performed at X5-GIF, CERN's gamma irradiation facility. In this paper, the latest results are presented, together with an example of successful damage recovery technique.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000237142400023 158, (2006)

The ATLAS first level trigger is designed to reduce the LHC interaction rate from 1 GHz to 75-100 kHz. The first level muon trigger in the barrel is described together with test beam results and current commissioning and integration status at CERN.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000241637300003 53, (2006)

This paper presents the hardware architecture and the main features of the ICARUS trigger system. The ICARUS detector is a very massive liquid Argon Time Projection Chamber aimed at the study of some of the fundamental issues of astroparticle physics such as solar and atmospheric neutrino interactions, neutrinos following a Supernova explosion, neutrino oscillations with beams from particle accelerators and nucleon decay as predicted by Grand Unification Theories. The main feature of the proposed trigger design is its "segmentation," i.e:, the capability to trigger different sectors of the detector on different events allowing for the efficient detection of rare events.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000240242900005 54, (2007)

ATLAS is one of the four experiments under construction along the Large Hadron Collider (LHC) ring at CERN. The LHC will produce interactions at a center-of-mass energy equal to root s = 14 TeV with a frequency of 40 MHz. The detector consists of more than 140 million electronic channels. The challenging experimental environment and the extreme detector complexity impose the necessity of a common, scalable, distributed monitoring framework, which can be tuned for optimal use by different ATLAS sub-detectors at the various levels of the ATLAS data flow. This paper presents the architecture of this monitoring software framework and describes its current implementation, which has already been used at the ATLAS beam test activity in 2004. Preliminary performance results, obtained on a computer cluster consisting of 700 nodes, will also be presented, showing that the performance of the current implementation is within the range of the final ATLAS requirements.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000247391500013 581, (2007)

The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton proton collisions from beams crossing at 40 MHz. At the design luminosity of 1034 cm(-2) s(-1) there are on average 23 collisions per bunch crossing. A three-level trigger system will select potentially interesting events in order to reduce the readout rate to about 200 Hz. The first trigger level is implemented in custom-built electronics and makes an initial fast selection based on detector data of coarse granularity. It has to reduce the rate by a factor of 104 to less than 100 kHz. The other two consecutive trigger levels are in software and run on PC farms. We present an overview of the first-level trigger system and report on the current installation status. Moreover, we show analysis results of cosmic-ray data recorded in situ at the ATLAS experimental site with final or close-to-final hardware. (C) 2007 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:59 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000251039100104 3,S08003 (2008)

The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000258875900010 4,P04010 (2009)

The ATLAS Level-1 Muon Barrel Trigger is one of the main elements of the first stage of event selection of the ATLAS experiment at the Large Hadron Collider. The challenge of the Level-1 system is a reduction of the event rate from a collision rate of 40 MHz by a factor 103, using simple algorithms that can be executed in highly parallel custom electronics with a latency of the order of 1 mu s. The input stage of the Level-1 Muon consists of an array of processors receiving the full granularity of data from a dedicated detector (Resistive Plate Chambers in the Barrel). This first stage of the algorithm is performed directly on-detector, while the final stage is performed in boards mounted in the counting room, by the so-called off-detector electronics.The trigger algorithm is executed within a fixed latency, its real-time output is the multiplicity of muon candidates passing a set of programmable p(T) thresholds, and their topological information. The detector system and the trigger electronics are designed to achieve a safe bunch-crossing identification. In order to optimize design effort and cost, the trigger system integrates also the readout of the detector, with its own requirements on time resolution and overall data bandwidth. We present the detailed functional requirements of the Level-1 Muon Barrel system, its architecture, implementation and construction.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000265878300010 598, (2009)

In 2004, a combined system test was performed in the H8 beam line at the CERN SPS with a setup reproducing the geometry of sectors of the ATLAS Muon Spectrometer, formed by three stations of Monitored Drift Tubes (MDT). The full ATLAS analysis chain Was used to obtain the results presented in this paper. The basic design performances of the Won Spectrometer were verified. The stability of MDT calibration constants, the alignment system using optical devices and high energy tracks, as well as the intrinsic sagitta resolution of the Muon Spectrometer were studied and found to agree with expectations. The reconstruction of muon tracks using the combined information from both the Inner Detector and the Muon Spectrometer are also presented. (C) 2008 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000262768300006 70, (2010)

The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolution. The uniformity of the electromagnetic barrel calorimeter response along eta (averaged over phi) is measured at the percent level using minimum ionizing cosmic muons. Finally, studies of electromagnetic showers from radiative muons have been used to cross-check the Monte Carlo simulation. The performance results obtained using the ATLAS readout, data acquisition, and reconstruction software indicate that the liquid argon calorimeter is well-prepared for collisions at the dawn of the LHC era.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285200000011 70, (2010)

The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29(-0.04)(+0.05))% in the barrel and (0.54(-0.04)(+0.06))% in the endcaps. The same data are used to measure the drift velocity of ionization electrons in liquid argon, which is found to be 4.61 +/- 0.07 mm/mu s at 88.5 K and 1 kV/mm.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285200000012 70, (2010)

The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285200000013 70, (2010)

The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285200000015 105,161801 (2010)

A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the LHC and correspond to an integrated luminosity of 315 nb(-1) collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% C. L. the q* mass interval 0: 30< m(q)*< 1:26 TeV, extending the reach of previous experiments.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000282753000004 ,056 (2010)

More than half a million minimum-bias events of LHC collision data were collected by the ATLAS experiment in December 2009 at centre-of-mass energies of 0.9 TeV and 2.36 TeV. This paper reports on studies of the initial performance of the ATLAS detector from these data. Comparisons between data and Monte Carlo predictions are shown for distributions of several track- and calorimeter-based quantities. The good performance of the ATLAS detector in these first data gives confidence for successful running at higher energies.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000286230100001 57, (2010)

The readout data of ATLAS' resistive plate chamber muon spectrometer are collected by the front-end electronics and transferred via optical fibers to the readout driver (ROD) boards in the counting room. Each ROD arranges all the data fragments of one sector of the spectrometer in a unique event. This is made by the Event Builder logic, a cluster of finite state machines that parses the fragments, checks their syntax, and builds an event containing all the sector data. In this paper, we describe the Builder Monitor, developed to analyze the Event Builder timing performance. It is designed around a 32-bit soft-core microprocessor embedded in the same field-programmable gate array hosting the Event Builder logic. This approach makes it possible to track the algorithm execution. The monitor performs real-time and statistical analysis of the state machine dynamics. The microprocessor is interfaced with custom peripherals, which read out the state registers and fill histograms and transfer them via direct memory access to the processor memory. The Builder Monitor also measures the elapsed time for each event and its length, and keeps track of status words and errors.We describe the hardware-software codesign of the Builder Monitor and the role played by the custom peripherals.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000276678900007 688, (2010)

The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range vertical bar eta vertical bar < 2.5 and p(T) > 500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity eta = 0 is measured to be 1.333 +/- 0.003(stat.) +/- 0.040(syst.), which is 5-15% higher than the Monte Carlo models predict. 2010 Published by Elsevier B.V.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000286150500001 70, (2010)

The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285200000014 55, (2008)

During 2006 and spring 2007, integration and commissioning of trigger and data acquisition (TDAQ) equipment in the ATLAS experimental area has progressed. Much of the work has focused on a final prototype setup consisting of around eighty computers representing a subset of the full TDAQ system. There have been a series of technical runs using this setup. Various tests have been run including those where around 6 k Level-1 preselected simulated proton-proton events have been processed in a loop mode through the trigger and dataflow chains. The system included the readout buffers containing the events, event building, second level and third level trigger processors. Aspects critical for the final system, such as event processing times, have been studied using different trigger algorithms as well as the different dataflow components.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000253224700017 55, (2008)

The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting events in order to reduce the read-out rate to about 200 Hz. The first trigger level is implemented in custom-built electronics and makes an initial fast selection based on detector data of coarse granularity. It has to reduce the rate by a factor of 104 to less than 100 kHz. The other two consecutive trigger levels are in software and run on PC farms. We present an overview of the first-level central trigger and the muon barrel trigger system and report on the current installation status. Moreover, we show analysis results of cosmic-ray data recorded in situ at the ATLAS experimental site with final or close-to-final hardware.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000253224700022 55, (2008)

The spectrometer of the ATLAS experiment has been designed to identify muon tracks with transverse momenta up to 1 TeV/c. Its barrel section is made of Monitored Drift Tubes and Resistive Plate Chambers (RPCs) arranged into 32 sectors, to form two wheels surrounding the interaction point. The RPC subsystem provides the Level-1 trigger in the barrel and it is read out by a specific DAQ system. On-detector electronics pack the RPC data in frames with an event number assigned by the trigger logic and transmit them to the counting room optically. Data from each sector are then routed together to a Read-Out Driver (ROD) board. This is a custom processor that parses the frames, checks their coherence and builds a data structure for all the RPCs of one of the 32 sectors of the spectrometer. Each ROD sends the event fragments to a Read-Out Buffer for further event building and analysis.The ROD is a VME64x board, designed around two Xilinx Virtex-II FPGAs and an ARM7 microcontroller. In this paper we describe the system architecture, the event binding algorithms and the monitoring features embedded into the design. The board is in production and will be deployed in the first ATLAS runs.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000253224700043 593, (2008)

We describe a system test of the ATLAS muon spectrometer performed at the H8 beam line of the CERN Super-Proton-Synchrotron (SPS) during 2003. The setup includes one barrel tower made of six Monitored Drift Tube chambers equipped with an alignment system and four Resistive Plate Chambers, and one end-cap octant consisting of six end-cap MDT equipped with an alignment system and one triplet and two doublets of Thin Gap Chambers. Many system aspects of the muon spectrometer have been studied with this setup, from the performance of the precision and trigger chambers to the capability to align the precision chambers at the level of a few tens of micrometers and to operate the muon trigger at the crossing frequency of the LHC. (C) 2008 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000259120700007 581, (2007)

Extensive tests with cosmic rays were performed with Resistive Plate Chamber (RPC) trigger chambers belonging to 6 muon stations of sector 13 installed in the ATLAS muon spectrometer. We illustrate the results of this pre-commissioning phase, which represents a test bench for the final commissioning of the ATLAS RPC system with cosmic rays. (C) 2007 Elsevier B.V. All rights reserved.]]> Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000251039100043 105, (2010)

A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the LHC and correspond to an integrated luminosity of 315nb? collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% C.L. the q* mass interval 0.30 Thu, 09 Feb 2012 12:07:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=MEDLINE%3A21230962 70, (2010)

The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector has successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems' precision is well below the design value of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.]]> Thu, 09 Feb 2012 12:07:57 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000285208000023 105,252303 (2010)

By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.]]> Thu, 09 Feb 2012 12:07:57 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000286750400009 578, (2004)

Inclusive K(S)(0)K(S)(0) production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb(-1). Two states are observed at masses of 1537(-8)(+9) MeV and 1726 +/- 7 MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f'(2)(1525). The state at 1726 MeV may be the glueball candidate f(0)(1710). However, it's width of 38(-14)(+20) MeV is narrower than 125 +/- 10 MeV observed by previous experiments for the f(0)(1710). (C) 2003 Elsevier B.V. All rights reserved.]]> Wed, 08 Feb 2012 18:11:23 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000187730800005 84,113003 (2011)

The analysis of the recent neutral-current neutrino-nucleus scattering cross sections measured by the MiniBooNE Collaboration requires relativistic theoretical descriptions also accounting for the role of final-state interactions. In this work, we evaluate differential cross sections with the relativistic distorted-wave impulse approximation and with the relativistic Green's function model to investigate the sensitivity to final-state interactions. The role of the strange-quark content of the nucleon form factors is also discussed.]]> Wed, 08 Feb 2012 17:55:34 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000297936800003 ,002 (2004)

Following the approach of Callan and Thorlacius applied to the superstring, we derive a supersymmetric extension of the non-local dissipative action of Caldeira and Leggett. The dissipative term turns out to be invariant under a group of superconformal transformations. When added to the usual kinetic term, it provides an example of supersymmetric dissipative quantum mechanics.]]> Wed, 08 Feb 2012 12:48:38 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000224125000002 654, (2007)

We present new precision measurements of the psi (2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements. while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi (2S) meson through the processes pp -> e(+)e(-) and pp -> J/psi + X -> e(+)e(-) + X. We measure the width to be Gamma = 290 +/- 25(sta) +/- 4(sys) keV and the combination of partial widths Gamma(+)(-)(e)(e) - Gamma pp/Gamma = 579 +/- 38(sta) +/- 36(sys) meV, which represent the most precise measurements to date. (C) 2007 Elsevier B.V. All rights reserved.]]> Wed, 08 Feb 2012 12:29:33 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000250282600004 ,034 (2011)

The cross section for a Majorana Dark Matter particle annihilating into light fermions is helicity suppressed. We show that, if the Dark Matter is the neutral Majorana component of a multiplet which is charged under the electroweak interactions of the Standard Model, the emission of gauge bosons from the initial state lifts the suppression and allows an s-wave annihilation. The resulting energy spectra of stable Standard Model particles are importantly affected. This has an impact on indirect searches for Dark Matter.]]> Wed, 08 Feb 2012 09:39:38 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000296767600034 119, (2004)

Monte Carlo (MC) simulation has been used as a validation tool for a hydrodynamical model of hot carrier transport in semiconductors based upon the maximum entropy closure and originally introduced by Anile and coworkers. The Monte Carlo code has been internally checked via its application to the problem of the hot electron propagation in a n(+) nn(+) Si ballistic diode, modeling a MOSFET channel, requiring the simultaneous and self-consisting solution of the field and Boltzmann equations.]]> Tue, 07 Feb 2012 14:40:49 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000229572500006 36,045202 (2009)

The (15)N(p,gamma)(16)O reaction controls the passage of nucleosynthetic material from the first to the second carbon-nitrogen-oxygen (CNO) cycle. A direct measurement of the total (15)N(p,gamma)(16)O cross section at energies corresponding to hydrogen burning in novae is presented here. Data have been taken at 90-230 keV center-of-mass energy using a windowless gas target filled with nitrogen of natural isotopic composition and a bismuth germanate summing detector. The cross section is found to be a factor 2 lower than previously believed.]]> Tue, 07 Feb 2012 13:29:58 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000264386700014 779, (2006)

Deep underground in Gran Sasso National Laboratory (Italy), at the LUNA facility, the cross section of the N-14(p, gamma) O-15, the slowest process of the CNO cycle, has been measured at energies much lower than achieved before. Using a 400 kV accelerator, a windowless gas target and a 4 pi BGO summing detector, direct cross section data has been obtained down to 70 keV, reaching a value of 0.24 picobarn, corresponding to an S-factor of 1.74 +/- 0.14(stat) +/- 0.14(syst) keV barn. The Gamow peak has been covered by direct experimental data for several scenarios of stable and explosive hydrogen burning. The wy strength of the 259 keV resonance has been re-measured obtaining 12.8 +/- 0.3(stat) +/- 0.4(syst) meV. The stellar reaction rate has been calculated for temperatures 0.09 x 10(9) - 0.3 x 10(9) K. A complete description of the experiment is here presented, including the impact of the present data on nucleosynthesis in AGB stars. (c) 2006 Elsevier B.V. All rights reserved.]]> Tue, 07 Feb 2012 13:18:06 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000242412600014 31, (2005)

In the hot interiors of dense stellar plasma, the equilibrium CNO cycle converts most of the carbon and oxygen into nitrogen. We discuss implications of new measurements concerning the modified thermonuclear CNO reaction rates and the chemical abundance evolution of the stellar core as a function of the temperature. We show that strong CNO abundance variations occur if non-extensive statistical effects, connected to memory plasma effects and long-range force, are taken into account.]]> Tue, 07 Feb 2012 13:06:36 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000232575600091 32,L12308 (2005)

[ 1] We monitored radon anomalies before, during and after the recent paroxysmal eruptions of Stromboli. Major eruptive events are preceded by relative minima in radon emissions at stations located at the base of the cone, whereas three of the summit stations reached peak values (similar to 20,000 Bq/m(3) or higher) 12 to 14 days before major eruptions, and are nearly coeval with earth tides. Radon emissions at/or above such high threshold values are proposed to result from the dynamic response of the fracture network due to degassing processes associated with magma ascent. Relative minima recorded at the base of the cone are related to fractures' self-sealing within the hydrothermal system, eventually coupled with the atmospheric stack-effect. The coexistence of the above anomalies is interpreted as the first precursory signals to major eruptive events.]]> Tue, 07 Feb 2012 13:06:36 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000230169800002 26, (2007)

Current methods for bladder cancer investigation involve cystoscopy, ultrasound scanning, and contrast urography, with additional information provided by cytology. These methods, although having a high detection rate, are expensive, time-consuming, invasive, and uncomfortable. Therefore, there is a need for an inexpensive, non invasive, quick, and simple investigation with a high sensitivity and specificity. In this study we evaluate the use of an in vivo electromagnetic (EM) interaction as a non invasive method for detecting cancer. A clinical trial was designed and completed. The main trial target was the feasibility assessment of the novel method by comparing its results with standard cystoscopy. A physical discussion of the EM interaction with bladder cancer tissue is presented. One hundred and fourteen patients referred for cystoscopy by microscopic or gross haematuria, irritative voiding symptoms, or suspected bladder tumor at ultrasound were first submitted to EM scan by means of the TRIMprob (TM) system. Cystoscopy was performed on each patient after the TRIMprob (TM) examination. Comparison between EM and cystoscopy results provides a high level of agreement (Cohen's K=0.77, p<0.001). The TRIMprob (TM) performance in malignant cancer cells detection suggests that this in vivo EM waves method is also worth investigating for routine diagnostic procedures.]]> Tue, 07 Feb 2012 13:03:39 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000247722700005 50, (2006)

In this paper an analysis of the Stirling cycle in thermoeconomic terms is developed using the entropy generation. In the thermoeconomic optimization of an irreversible Stirling heat pump cycle the F function has been introduced to evaluate the optimum for the higher and lower sources temperature ratio in the cycle: this ratio represents the value which optimizes the cycle itself. The variation of the function F is proportional to the variation of the entropy generation, the maxima and minima of F has been evaluated in a previous paper without giving the physical foundation of the method. We investigate the groundwork of this approach: to study the upper and lower limits of F function allows to determine the cycle stability and the optimization conditions. The optimization consists in the best COP at the least cost. The principle of maximum variation for the entropy generation becomes the analytic foundation of the optimization method in the thermoeconomic analysis for an irreversible Stirling heat pump cycle.]]> Tue, 07 Feb 2012 13:03:39 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000236782300068 27, (2006)

In stars, four hydrogen nuclei are converted into a helium nucleus in two competing nuclear fusion processes, namely the proton-proton chain (p-p chain) and the carbon-nitrogen-oxygen (CNO) cycle. For temperatures above 20 million kelvin, the CNO cycle dominates energy production, and its rate is determined by the slowest process, the (14)N(p, gamma)(15)O radiative capture reaction. This reaction proceeds through direct and resonant capture into the ground state and several excited states in (15)O. High energy data for capture into each of these states can be extrapolated to stellar energies using an R-matrix fit. The results from several recent extrapolation studies are discussed. A new experiment at the L UNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in Italy's Gran Sasso laboratory measures the total cross section of the (14)N(p, gamma)(15)O reaction with a windowless gas target and a 4 pi BGO summing detector, down to center of mass energies as low as 70 keV. After reviewing time characteristics of the LUNA facility, the main features of this experiment are discussed, as well as astrophysical scenarios where cross section data in the energy range covered have a direct impact, without any extrapolation.]]> Tue, 07 Feb 2012 13:03:39 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000208079500025 27, (2006)

The (3)He((4)He, gamma)(7)Be reaction is the key process for the production of (7)Be and (8)B neutrinos in the Sun. We have designed a new experimental setup to study this reaction with high accuracy at low energies using two different experimental techniques. The first method consists in measuring the prompt capture gamma-ray transitions with an ultra-low background germanium detector heavily shielded and placed at close distance from a (3)He windowless gas target. With another fully shielded large-volume germanium detector we will also measure the beta-decay of the (7)Be residual nuclei. The aim of the experiment is to reduce the error on the astrophysical factor S(3,4) to 4%.]]> Tue, 07 Feb 2012 13:03:39 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000208079500027 572, (2007)

One year survey of indoor radon concentrations was carried out in public buildings, schools and dwellings of the neighbouring small towns of Nichelino and Castagnole Piemonte, nearby Turin, Piedmont (Italy), as part of a long term assessment of local radon levels. Three kinds of detectors have been deployed for nearly 500 exposures: electrects, solid state nuclear track detectors and a continuous online monitor. A log-normal model was applied to estimate the fraction of dwellings with high radon concentration. The resulting effective dose-equivalent for the inhabitants of Castagnole Piemonte and Nichelino, calculated from the geometric means, is 0.7 and 0.5 mSv yr(-1) respectively. (c) 2006 Elsevier B.V. All rights reserved.]]> Tue, 07 Feb 2012 12:59:11 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000245129400085 61, (2008)

New experimental approach to study meson photoproduction in nuclei is discussed. It is based on the measurement of the recoil nucleon as a tagger for identification of the initial step of reaction. Propagation of mesons and nucleons within a nucleus is described by the Intra-Nuclear Cascade (INC) model. Simulations and preliminary experimental data for the deuteron target obtained at GRAAL are presented. (c) 2008 Elsevier B.V. All rights reserved.]]> Tue, 07 Feb 2012 12:54:13 +0100 http://www.infn.it/pubblicazioni/dettaglio.php?UT=WOS%3A000257886300036