293 research outputs found

    "Willingness to pay for security" bei Passagierkontrollen am Flughafen: zu den individuellen Kosten öffentlicher Sicherheit

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    "In dem Beitrag geht es um die Erklärung der Bereitschaft der Bürger, Kosten in Form von zusätzlicher Wartezeit am Flughafen in Kauf zu nehmen, um durch eine intensivere Kontrolle aller Flugpassagiere die Sicherheit zu erhöhen. Es werden eine Reihe von Hypothesen an den Daten einer repräsentativen telefonischen Bevölkerungsbefragung (N = 2176) überprüft. Dabei zeigt sich, dass die Angst vor terroristischen Anschlägen, soziale, ökonomische und existenzielle Ängste, Punitivität und Nutzenerwartungen im Hinblick auf neue staatliche Kontroll- und Überwachungsmaßnahmen die Bereitschaft, zusätzliche Wartezeiten bei der Kontrolle in Kauf zu nehmen, fördern. Die Präferenz für ein 'Social Sorting' von Flugpassagieren im Sinne einer selektiven Passagierkontrolle nach bestimmten 'verdächtigen' Kriterien (Nationalität, äußeres Erscheinungsbild) vermindert dagegen diese Bereitschaft." (Autorenreferat)"This article is a theory-driven multivariate statistical analysis of the willingness to pay for an increase of security in terms of additional waiting time at airports thereby imposing (additional) time-costs on airline passengers. A multivariate regression mode) is tested with data from a large German telephone survey (N = 2176). The results of the analysis indicate that fear of terrorism as well as economic and existential fears, punitive attitudes, and expected benefits attributed to new surveillance measures are predictors of the willingness to pay for security as they have positive effects on the dependent variable. On the other hand social sorting in terms of targeting of passengers for security screening based on 'suspicious' characteristics like nationality and appearance has a negative effect on the willingness to pay for security in terms of additional waiting time at airports." (author's abstract

    Particle production as a function of charged-particle flattenicity in pp collisions at s\sqrt{s} = 13 TeV

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    International audienceThis paper reports the first measurement of the transverse momentum (pTp_{\mathrm{T}}) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at s=13\sqrt{s}=13 TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, 2.8<η<5.12.8<\eta<5.1 and 3.7<η<1.7-3.7<\eta<-1.7. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases towards larger pTp_{\mathrm{T}} due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to pT=20p_{\mathrm{T}}=20 GeV/cc. The event selection requires at least one charged particle produced in the pseudorapidity interval η<1|\eta|<1. The measured pTp_{\mathrm{T}} distributions, average pTp_{\mathrm{T}}, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using PYTHIA 8 based on color strings and EPOS LHC. The modification of the pTp_{\mathrm{T}}-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate pTp_{\mathrm{T}} (2<pT<82<p_{\mathrm{T}}<8 GeV/cc), and approaches the vicinity of unity at higher pTp_{\mathrm{T}}. The results are qualitatively described by PYTHIA, and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator

    Exclusive four pion photoproduction in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThe intense photon fluxes from relativistic nuclei provide an opportunity to study photonuclear interactions in ultraperipheral collisions. The measurement of coherently photoproduced π+ππ+π\pi^+\pi^-\pi^+\pi^- final states in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV is presented for the first time. The cross section, dσ\sigma/dyy, times the branching ratio (ρπ+π+ππ\rho\rightarrow \pi^+ \pi^+ \pi^- \pi^-) is found to be 47.8±2.3 (stat.)±7.7 (syst.)47.8\pm2.3~\rm{(stat.)}\pm7.7~\rm{(syst.)} mb in the rapidity interval y<0.5|y| < 0.5. The invariant mass distribution is not well described with a single Breit-Wigner resonance. The production of two interfering resonances, ρ(1450)\rho(1450) and ρ(1700)\rho(1700), provides a good description of the data. The values of the masses (mm) and widths (Γ\Gamma) of the resonances extracted from the fit are m1=1385±14 (stat.)±3 (syst.)m_{1}=1385\pm14~\rm{(stat.)}\pm3~\rm{(syst.)} MeV/c2c^2, Γ1=431±36 (stat.)±82 (syst.)\Gamma_{1}=431\pm36~\rm{(stat.)}\pm82~\rm{(syst.)} MeV/c2c^2, m2=1663±13 (stat.)±22 (syst.)m_{2}=1663\pm13~\rm{(stat.)}\pm22~\rm{(syst.)} MeV/c2c^2 and Γ2=357±31 (stat.)±49 (syst.)\Gamma_{2}=357 \pm31~\rm{(stat.)}\pm49~\rm{(syst.)} MeV/c2c^2, respectively. The measured cross sections times the branching ratios are compared to recent theoretical predictions

    Measurement of Λ3H{}_{\Lambda}^{3}\mathrm{H} production in Pb-Pb collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    International audienceThe first measurement of Λ3H_{\Lambda}^{3}\mathrm{H} and Λ3H^3_ {\overline{\Lambda}}\overline{\mathrm{H}} differential production with respect to transverse momentum and centrality in Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02~TeV is presented. The Λ3H_{\Lambda}^{3}\mathrm{H} has been reconstructed via its two-charged-body decay channel, i.e., Λ3H3He+π_{\Lambda}^{3}\mathrm{H} \rightarrow {}^{3}\mathrm{He} + \pi^{-}. A Blast-Wave model fit of the pTp_{\rm T}-differential spectra of all nuclear species measured by the ALICE collaboration suggests that the Λ3H_{\Lambda}^{3}\mathrm{H} kinetic freeze-out surface is consistent with that of other nuclei. The ratio between the integrated yields of Λ3H_{\Lambda}^{3}\mathrm{H} and 3He^3\mathrm{He} is compared to predictions from the statistical hadronisation model and the coalescence model, with the latter being favoured by the presented measurements

    Multimuons in cosmic-ray events as seen in ALICE at the LHC

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    International audienceALICE is a large experiment at the CERN Large Hadron Collider. Located 52 meters underground, its detectors are suitable to measure muons produced by cosmic-ray interactions in the atmosphere. In this paper, the studies of the cosmic muons registered by ALICE during Run 2 (2015--2018) are described. The analysis is limited to multimuon events defined as events with more than four detected muons (Nμ>4N_\mu>4) and in the zenith angle range 01000^{\circ}100) obtained with QGSJET and SIBYLL is compatible with the data, while EPOS-LHC produces a significantly lower rate (55%55\% of the measured rate). For both QGSJET and SIBYLL, the rate is close to the data when the composition is assumed to be dominated by heavy elements, an outcome compatible with the average energy Eprim1017E_\mathrm{prim} \sim 10^{17}~eV of these events. This result places significant constraints on more exotic production mechanisms

    Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at √sNN = 5.02 TeV

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    The first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons is presented. The ρ0 mesons are reconstructed through their decay into a pion pair. The measured anisotropy corresponds to the amplitude of the cos(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb−Pb collisions at a center-of-mass energy of sNN−−−√ = 5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations, which describe the measurement, explain the cos(2ϕ) anisotropy as the result of a quantum interference effect at the femtometer scale that arises from the ambiguity as to which of the nuclei is the source of the photon in the interaction

    Investigating strangeness enhancement in jet and medium via ϕ\phi(1020) production in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThis work aims to differentiate strangeness produced from hard processes (jet-like) and softer processes (underlying event) by measuring the angular correlation between a high-momentum trigger hadron (h) acting as a jet-proxy and a produced strange hadron (ϕ(1020)\phi(1020) meson). Measuring hϕ-\phi correlations at midrapidity in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV as a function of event multiplicity provides insight into the microscopic origin of strangeness enhancement in small collision systems. The jet-like and the underlying-event-like strangeness production are investigated as a function of event multiplicity. They are also compared between a lower and higher momentum region. The evolution of the per-trigger yields within the near-side (aligned with the trigger hadron) and away-side (in the opposite direction of the trigger hadron) jet is studied separately, allowing for the characterization of two distinct jet-like production regimes. Furthermore, the hϕ-\phi correlations within the underlying event give access to a production regime dominated by soft production processes, which can be compared directly to the in-jet production. Comparisons between hϕ-\phi and dihadron correlations show that the observed strangeness enhancement is largely driven by the underlying event, where the ϕ/h\phi/\mathrm{h} ratio is significantly larger than within the jet regions. As multiplicity increases, the fraction of the total ϕ(1020)\phi(1020) yield coming from jets decreases compared to the underlying event production, leading to high-multiplicity events being dominated by the increased strangeness production from the underlying event
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