461 research outputs found
Accuracy assessment of the MUF(3000) nowcasting for PECASUS Space Weather services
No full textThe Pan-European Consortium for Aviation Space Weather User Services (PECASUS) is one of the three global Space Weather Centers appointed by the International Civil Aviation Organization (ICAO) to generate Space Weather advisories for aviation users. One of the key operational 24/7 products developed by INGV for the HF domain is the MUF(3000) nowcasting, based on a mapping procedure over Europe, which makes use of the available real-time measurements in different locations, and the Ordinary Kriging method for spatial interpolation. The outputs of this procedure have been analysed during three strong geomagnetic storms, and the results have been compared on the basis of the Root Mean Square Error values obtained between predicted and measured MUF(3000) values at two different test stations. A good accuracy is achieved during the considered storm periods, being the overall Root Mean Square Error values at the test stations less than 2 MHz. However, particular cases show that this method could miss possible sudden ionospheric perturbations, and the effect of erroneous data on the accuracy estimation.PublishedRome (Italy)2A. Fisica dell'alta atmosfer
Transverse momentum, rapidity, and centrality dependence of inclusive charged-particle production in root s(NN)=5.02 TeV p+Pb collisions measured by the ATLAS experiment
No full textMeasurements of the per-event charged-particle yield as a function of the charged-particle transverse momentum and rapidity are performed using p + Pbcollision data collected by the ATLAS experiment at the LHC at a centre-of-mass energy of root sNN= 5.02 TeV. Charged particles are reconstructed over pseudorapidity |eta| < 2.3and transverse momentum between 0.1GeVand 22GeVin a dataset corresponding to an integrated luminosity of 1 mu b(-1). The results are presented in the form of chargedparticle nuclear modification factors, where the p + Pbcharged-particle multiplicities are compared between central and peripheral p + Pbcollisions as well as to charged-particle cross sections measured in ppcollisions. The p + Pbcollision centrality is characterized by the total transverse energy measured in -4.9<eta<-3.1, which is in the direction of the outgoing lead beam. Three different estimations of the number of nucleons participating in the p + Pbcollision are carried out using the Glauber model and two Glauber-Gribov colour-fluctuation extensions to the Glauber model. The values of the nuclear modification factors are found to vary significantly as a function of rapidity and transverse momentum. Abroad peak is observed for all centralities and rapidities in the nuclear modification factors for chargedparticle transverse momentum values around 3GeV. The magnitude of the peak increases for more central collisions as well as rapidity ranges closer to the direction of the outgoing lead nucleus. (C) 2016 The Author(s). Published by Elsevier B.V
Measurement of the differential cross-section of B+ meson production in pp collisions at root s=7 TeV at ATLAS
No full textThe production cross-section of B+ mesons is measured as a function of transverse momentum p T and rapidity y in proton-proton collisions at centre-of-mass energy root s = 7 TeV, using 2.4 fb(-1) of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < p(T) < 120 GeV and vertical bar y vertical bar < 2.25, are compared to next-to-leading-order theoretical predictions
Space Weather Effects Observed in the Northern Hemisphere during November 2021 Geomagnetic Storm: The Impacts on Plasmasphere, Ionosphere and Thermosphere Systems
No full textOn 3 November 2021, an interplanetary coronal mass ejection impacted the Earth’s magnetosphere leading to a relevant geomagnetic storm (Kp = 8-), the most intense event that occurred so far during the rising phase of solar cycle 25. This work presents the state of the solar wind before and during the geomagnetic storm, as well as the response of the plasmasphere–ionosphere–thermosphere system in the European sector. To investigate the longitudinal differences, the ionosphere–thermosphere response of the American sector was also analyzed. The plasmasphere dynamics was investigated through field line resonances detected at the European quasi-Meridional Magnetometer Array, while the ionosphere was investigated through the combined use of ionospheric parameters (mainly the critical frequency of the F2 layer, foF2) from ionosondes and Total Electron Content (TEC) obtained from Global Navigation Satellite System receivers at four locations in the European sector, and at three locations in the American one. An original method was used to retrieve aeronomic parameters from observed electron concentration in the ionospheric F region. During the analyzed interval, the plasmasphere, originally in a state of saturation, was eroded up to two Earth’s radii, and only partially recovered after the main phase of the storm. The possible formation of a drainage plume is also observed. We observed variations in the ionospheric parameters with negative and positive phase and reported longitudinal and latitudinal dependence of storm features in the European sector. The relative behavior between foF2 and TEC data is also discussed in order to speculate about the possible role of the topside ionosphere and plasmasphere response at the investigated European site. The American sector analysis revealed negative storm signatures in electron concentration at the F2 region. Neutral composition and temperature changes are shown to be the main reason for the observed decrease of electron concentration in the American sector
Z boson production in p + Pb collisions at √sNN = 5.02 TeV measured with the ATLAS detector
No full textThe ATLAS Collaboration measures the inclusive production of Z bosons via their decays into electron
and muon pairs in p + Pb collisions at √sNN = 5.02 TeV at the Large Hadron Collider. The measurements
are made using data corresponding to integrated luminosities of 29.4 and 28.1 nb−1 for Z → ee and Z →
μμ, respectively. The results from the two channels are consistent and combined to obtain a cross section
times the Z → branching ratio, integrated over the rapidity region |y∗
Z| < 3.5, of 139.8 ± 4.8 (statistical) ±
6.2 (systematic) ± 3.8 (luminosity) nb. Differential cross sections are presented as functions of the Z boson
rapidity and transverse momentum and compared with models based on parton distributions both with and
without nuclear corrections. The centrality dependence of Z boson production in p + Pb collisions is measured
and analyzed within the framework of a standard Glauber model and the model’s extension for fluctuations of
the underlying nucleon-nucleon scattering cross section
Evidence of W gamma gamma Production in pp Collisions at root s=8 TeV and Limits on Anomalous Quartic Gauge Couplings with the ATLAS Detector
No full textPublished by the American Physical Society under the terms of
the Creative Commons Attribution 3.0 License. Further distribution
of this work must maintain attribution to the author(s) and
the published article’s title, journal citation, and DOISCOAP
Study of the rare decays of B0s and B0 into muon pairs from data collected during the LHC Run 1 with the ATLAS detector
No full textSee paper for full list of authors - Comments: 29 pages plus author list + cover pages (46 pages total), 9 figures, 5 tables, submitted to Eur. Phys. J. C., regular article. All figures including auxiliary figures are available at this http URLInternational audienceA study of the decays B0→μ+μ− and B0s→μ+μ− has been performed using data corresponding to an integrated luminosity of 25 fb−1 of 7 TeV and 8 TeV proton--proton collisions collected with the ATLAS detector during the LHC Run 1. For B0, an upper limit on the branching fraction is set at B(B0→μ+μ−)<4.2×10−10 at 95% confidence level. For B0s, the branching fraction B(B0s→μ+μ−)=(0.9+1.1−0.8)×10−9 is measured. The results are consistent with the Standard Model expectation with a p-value of 4.8%, corresponding to 2.0 standard deviations
Scintillation detectors based on silicon microfluidic channels
No full textMicrofluidic channels obtained by SU-8 photolithography and filled with liquid scintillators were recently demonstrated to be an interesting technology for the implementation of novel particle detectors.The main advantages of this approach are the intrinsic radiationresistance resulting from the simple microfluidic circulation of theactive medium and the possibility to manufacture devices with highspatial resolution and low material budget using microfabricationtechniques.Here we explore a different technological implementation of thisconcept, reporting on scintillating detectors based on siliconmicrofluidic channels. A process for manufacturing microfluidicdevices on silicon substrates, featuring microchannel arrays suitablefor light guiding, was developed. Such process can be in principlecombined with standard CMOS processing and lead to a tight integrationwith the readout photodetectors and electronics in the future.Several devices were manufactured, featuring microchannel geometriesdiffering in depth, width and pitch. A preliminary characterizationof the prototypes was performed by means of a photomultiplier tubecoupled to the microchannel ends, in order to detect the scintillationlight produced upon irradiation with beta particles from a90Sr source. The photoelectron spectra thusobtained were fitted with the expected output function in order toextract the light yield
Z boson production in p plus Pb collisions at root S-NN=5.02 TeV measured with the ATLAS detector
No full textThe ATLAS Collaboration measures the inclusive production of Z bosons via their decays into electron and muon pairs in p + Pb collisions at root S-NN = 5.02 TeV at the Large Hadron Collider. The measurements are made using data corresponding to integrated luminosities of 29.4 and 28.1 nb(-1) for Z -> ee and Z -> mu mu, respectively. The results from the two channels are consistent and combined to obtain a cross section times the Z -> ll branching ratio, integrated over the rapidity region vertical bar y(Z)*vertical bar < 3.5, of 139.8 +/- 4.8 (statistical) +/- 6.2 (systematic) +/- 3.8 (luminosity) nb. Differential cross sections are presented as functions of the Z boson rapidity and transverse momentum and compared with models based on parton distributions both with and without nuclear corrections. The centrality dependence of Z boson production in p + Pb collisions is measured and analyzed within the framework of a standard Glauber model and the model's extension for fluctuations of the underlying nucleon-nucleon scattering cross section
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