Browsing by Subject "Model"

Now showing 1 - 5 of 5
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    Open Access
    Measurement of D ⁎± , D ± and D s ± meson production cross sections in pp collisions at s = 7  TeV with the ATLAS detector
    (2016) Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Aben, R; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimoto, G; Akimov, A V; Alberghi, G L; Albert, J; Albrand, S; Alconada Verzini, M J; Aleksa, M
    The production of D∗±, D± and D± s charmed mesons has been measured with the ATLAS detector in pp collisions at √s = 7 TeV at the LHC, using data corresponding to an integrated luminosity of 280 nb−1. The charmed mesons have been reconstructed in the range of transverse momentum 3.5 < pT(D) < 100 GeV and pseudorapidity were measured for D∗± and D± production. The differential cross sections as a function of transverse momentum and pseudorapidity ｜η(D)｜ < 2.1. The next-to-leading-order QCD predictions are consistent with the data in the visible kinematic region within the large theoretical uncertainties. Using the visible D cross sections and an extrapolation to the full kinematic phase space, the strangeness-suppression factor in charm fragmentation, the fraction of charged non-strange D mesons produced in a vector state, and the total cross section of charm production at √s = 7 TeV were derived.
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    A model for the zeta potential of copper sulphide
    (Elsevier, 2014) Nduna, Moses; Lewis, Alison Emslie; Nortier, P
    A model is proposed for the zeta-potential versus pH curve of Covellite (CuS). The classical Gouy–Chapman–Stern treatment of the adsorption of protons is applied to a model surface derived from the crystallographic data. The surface charges are obtained by an original adaptation of the concepts from the MUSIC model to a sulphide, i.e. the analysis of the chemical bonding in Pauling’s electrostatic valence framework to derive partial surface charges. The authors develop a software for the fitting of p –pHcurves using IPHREEQC for the calculation of the zeta potential at each pH point and Matlab to drive the calculation of the whole pH set and the optimisation of the parameters: capacitances of the double layer,site densities, charges and acidity constants. The model successfully reproduces the experimental data,considering only two sulphided surface sites: introduction of an elemental sulphur layer or consideration of hydroxyl surface sites is not required to explain the charging behaviour of Covellite when carefully precipitated under nitrogen.
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    Open Access
    Multiplicity dependence of the average transverse momentum in pp, p–Pb, and Pb–Pb collisions at the LHC
    (2013) Abelev, B; Adam, J; Adamová, D; Adare, A M; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agocs, A G; Agostinelli, A; Ahammed, Z; Ahmad Masoodi, A; Ahmad, N; Ahmed, I; Ahn, S A; Ahn, S U; Aimo, I; Ajaz, M; Akindinov, A; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altini, V; Altinpinar, S; Altsybeev, I; Andrei, C; Andronic, A; Anguelov, V; Anielski, J
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    Open Access
    Search for Direct Top Squark Pair Production in Final States with One Isolated Lepton, Jets, and Missing Transverse Momentum in s = 7     TeV p p Collisions Using 4.7     fb − 1 of ATLAS Data
    (2012) Aad, G; Abajyan, T; Abbott, B; Abdallah, J; Abdel Khalek, S; Abdelalim, A A; Abdinov, O; Aben, R; Abi, B; Abolins, M; AbouZeid, O S; Abramowicz, H; Abreu, H; Acharya, B S; Adamczyk, L; Adams, D L; Addy, T N; Adelman, J; Adomeit, S; Adragna, P; Adye, T; Aefsky, S; Aguilar-Saavedra, J A; Agustoni, M; Aharrouche, M; Ahlen, S P; Ahles, F; Ahmad, A; Ahsan, M; Aielli, G; Akdogan, T; Åkesson, T P A
    A search is presented for direct top squark pair production in final states with one isolated electron or muon, jets, and missing transverse momentum in proton-proton collisions at root s = 7 TeV. ...
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    Open Access
    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in p p collisions at √s=13 TeV using the ATLAS detector
    (2016) Aaboud, M; Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Abeloos, B; Aben, R; AbouZeid, O S; Abraham, N L; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Agricola, J; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimov, A V; Alberghi, G L; Albert, J; Albrand, S
    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses proton--proton collision data corresponding to an integrated luminosity of 3.2 fb⁻¹ at √s=13 TeV collected in 2015 with the ATLAS detector at the Large Hadron Collider. Events are required to have at least one jet with a transverse momentum above 250 GeV and no leptons. Several signal regions are considered with increasing missing-transverse-momentum requirements between E miss T >250 GeV and E miss T >700 GeV. Good agreement is observed between the number of events in data and Standard Model predictions. The results are translated into exclusion limits in models with large extra spatial dimensions, pair production of weakly interacting dark-matter candidates, and the production of supersymmetric particles in several compressed scenarios.