5,902 research outputs found

    ATLAS RPC offline monitoring and data quality assessment

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    In this work several aspects of ATLAS RPC offline monitoring and data quality assessment are illustrated with cosmics data selected by RPC trigger. These correspond to trigger selection, front-end mapping, detection efficiency and occupancy, which are studied in terms of low level quantities such as: RPC off-line hits and standalone tracks. The tools and techniques presented are also extended to the forthcoming LHC p-p beam collisions.Comment: Poster section at ICHEP08, Philadelphia, USA, July 2008. 3 pages, LaTeX, 3 eps figure

    KLOE results at the Frascati ϕ\phi-factory DAΦ\PhiNE

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    The KLOE experiment at the Frascati ϕ\phi-factory DAΦ\PhiNE has collected about 0.5 fb1^{-1} of data till the end of the year 2002. These data allow to perform a wide physics program, ranging from the physics of charged and neutral kaons to radiative ϕ\phi-decays. Results are presented for the KLK_L lifetime and the semileptonic processes KS,LπeνK_{S,L} \to \pi e \nu. From the light meson spectroscopy program, results on the decays ϕf0(980)γ,a0(980)γ\phi \to f_0(980)\gamma, a_0(980)\gamma as well as ϕηγ,ηγ\phi \to \eta \gamma, \eta' \gamma are presented.Comment: 5 pages, 3 figures, Proceedings contribution to the 10th Int. Symposium on "Meson-Nucleon Physics and the Structure of the Nucleon" (MENU04), Beijing, China, Aug. 30 - Sept. 4, 200

    Cosmology of fermionic dark matter

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    We explore a model for a fermionic dark matter particle family which decouples from the rest of the partices when at least all standard model particles are in equilibrium. We calculate the allowed ranges for mass and chemical potential to be compatible with big bang nucleosynthesis (BBN) calculations and WMAP-data for a flat universe with dark energy. Futhermore we estimate the free streaming length for fermions and antifermions to allow comparison to large scale structure data (LLS). We find that for dark matter decoupling when all standard model particles are present even the least restrictive combined BBN calculation and WMAP results allow us to constrain the initial dark matter chemical potential to a highest value of 6.3 times the dark matter temperature. In this case the resulting mass range is at most 1.8 eV < m < 53 eV, where the upper bound scales linearly with the effective degrees of freedom at decoupling. From LSS we find that similar to ordinary warm dark matter models the particle mass has to be larger than approximately 500 eV (meaning the effective degrees of freedom at decoupling have to be > 1000) to be compatible with observations of the Ly alpha forest at high redshift, but still the dark matter chemical potential over temperature ratio can exceed unity.Comment: 14 pages, 13 figures; Submitted to Phys. Rev. Lett. D., minor changes after referee report: references added, several minor extensions (mostly to the introduction). Also conclusion extended with an additional summary plot to clarify the result

    Inverse Spin Hall Effect and Anomalous Hall Effect in a Two-Dimensional Electron Gas

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    We study the coupled dynamics of spin and charge currents in a two-dimensional electron gas in the transport diffusive regime. For systems with inversion symmetry there are established relations between the spin Hall effect, the anomalous Hall effect and the inverse spin Hall effect. However, in two-dimensional electron gases of semiconductors like GaAs, inversion symmetry is broken so that the standard arguments do not apply. We demonstrate that in the presence of a Rashba type of spin-orbit coupling (broken structural inversion symmetry) the anomalous Hall effect, the spin Hall and inverse spin Hall effect are substantially different effects. Furthermore we discuss the inverse spin Hall effect for a two-dimensional electron gas with Rashba and Dresselhaus spin-orbit coupling; our results agree with a recent experiment.Comment: 5 page

    Reply to Comment on: Hawking radiation from ultrashort laser pulse filaments

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    A comment by R. Schutzhold et al. raises possible concerns and questions regarding recent measurements of analogue Hawking radiation. We briefly reply to the opinions expressed in the comment and sustain that the origin of the radiation may be understood in terms of Hawking emission

    Quantum theory as a relevant framework for the statement of probabilistic and many-valued logic

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    Based on ideas of quantum theory of open systems we propose the consistent approach to the formulation of logic of plausible propositions. To this end we associate with every plausible proposition diagonal matrix of its likelihood and examine it as density matrix of relevant quantum system. We are showing that all logical connectives between plausible propositions can be represented as special positive valued transformations of these matrices. We demonstrate also the above transformations can be realized in relevant composite quantum systems by quantum engineering methods. The approach proposed allows one not only to reproduce and generalize results of well-known logical systems (Boolean, Lukasiewicz and so on) but also to classify and analyze from unified point of view various actual problems in psychophysics and social sciences.Comment: 7 page

    Depressive and anxiety symptoms screening in cardiac inpatients : a virtuous italian approach to psychocardiology

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    Despite the fact that American Heart Association (AHA) recommended a systematic screening for depression in cardiovascular inpatients, poor attention has been given to this issue. Furthermore, no specific guidelines exist for anxiety screening in cardiovascular inpatients. Thus, the aims of this study were to verify the feasibility of a depressive and anxiety symptoms screening protocol in an Italian hospital specializing in cardiovascular diseases and to evaluate both anxiety and depressive symptoms prevalence. A group of 2009 consecutive inpatients completed the 9-item Patient Health Questionnaire (PHQ-9) and the 7-item Generalized Anxiety Disorder (GAD-7). The rates of depressive and anxiety symptoms were almost 9% and 16% respectively. Men were less likely than women to experience both depressive and anxiety symptoms. Patients who were admitted to the heart failure unit reported higher risk of experiencing both symptoms compared to patients in other wards. Similarly, patients admitted to the cardiac surgery unit showed a higher risk of experiencing anxiety symptoms compared to other patients. The proposed screening procedure showed a good feasibility and acceptance. This study highlighted the importance of implementing a short screening procedure in hospitals dealing with cardiovascular inpatients to identify those individuals who require specific attention and interventions

    Scalar models for the generalized Chaplygin gas and the structure formation constraints

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    The generalized Chaplygin gas model represents an attempt to unify dark matter and dark energy. It is characterized by a fluid with an equation of state p=A/ραp = - A/\rho^\alpha. It can be obtained from a generalization of the DBI action for a scalar, tachyonic field. At background level, this model gives very good results, but it suffers from many drawbacks at perturbative level. We show that, while for background analysis it is possible to consider any value for α\alpha, the perturbative analysis must be restricted to positive values of α\alpha. This restriction can be circumvented if the origin of the generalized Chaplygin gas is traced back to a self-interacting scalar field, instead of the DBI action. But, in doing so, the predictions coming from formation of large scale structures reduce the generalized Chaplygin gas model to a kind of quintessence model, and the unification scenario is lost, if the scalar field is the canonical one. However, if the unification condition is imposed from the beginning as a prior, the model may remain competitive. More interesting results, concerning the unification program, are obtained if a non-canonical self-interacting scalar field, inspired by Rastall's theory of gravity, is imposed. In this case, an agreement with the background tests is possible.Comment: Latex file, 25 pages, 33 figures in eps format. New section on scalar models. Accepted for publication in Gravitation&Cosmolog

    Search for new phenomena in high-mass diphoton final states using 37 fb(-1) of proton-proton collisions collected at root(s) = 13 TeV with the ATLAS detector

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    Searches for new phenomena in high-mass diphoton final states with the ATLAS experiment at the LHC are presented. The analysis is based on pp collision data corresponding to an integrated luminosity of 36.7 fb(-1) at a centre-of-mass energy root s = 13 TeV recorded in 2015 and 2016. Searches are performed for resonances with spin 0, as predicted by theories with an extended Higgs sector, and for resonances with spin 2, using a warped extra-dimension model as a benchmark model, as well as for non-resonant signals, assuming a large extra-dimension scenario. No significant deviation from the Standard Model is observed. Upper limits are placed on the production cross section times branching ratio to two photons as a function of the resonance mass. In addition, lower limits are set on the ultraviolet cutoff scale in the large extra-dimensions model. (C) 2017 The Author(s). Published by Elsevier B.V
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