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Jalal Abdallah

Bio: Jalal Abdallah is an academic researcher from University of Texas at Arlington. The author has contributed to research in topics: Large Hadron Collider & Higgs boson. The author has an hindex of 111, co-authored 552 publications receiving 57550 citations. Previous affiliations of Jalal Abdallah include Autonomous University of Barcelona & Spanish National Research Council.


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01 Jan 2003
TL;DR: In this paper, a supersymmetric model was proposed to find R-hadrons in the DELPHI detector at the center-of-mass energies of 189 to 208 GeV, with an overall integrated luminosity of 609 Pb-1.
Abstract: In some supersymmetric models, the gluino ( $\tilde {\rm g}$ ) is predicted to be light and stable. In that case, it would hadronize to form R-hadrons. In these models, the missing energy signature of the lightest supersymmetric particle is no longer valid, even if R-parity is conserved. Therefore, such a gluino is not constrained by hadron collider results, which looked for the decay $\tilde {\rm g}\to{\rm q \bar q}\tilde \chi^0_1$ . Data collected by the DELPHI detector in 1994 at 91.2 GeV have been analysed to search for ${\rm q \bar q}\tilde {\rm g}\tilde {\rm g}$ events. No deviation from Standard Model predictions is observed and a gluino mass between 2 and 18 GeV/c2 is excluded at the 95% confidence level in these models. Then, R-hadrons produced in the squark decays were searched for in the data collected by DELPHI at the centre-of-mass energies of 189 to 208 GeV, corresponding to an overall integrated luminosity of 609 Pb-1. The observed number of events is in agreement with the Standard Model predictions. Limits at 95% confidence level are derived on the squark masses from the excluded regions in the plane ( $m_{\tilde {\rm q} 1}, m_{\tilde {\rm g}}$ ) $m_{\tilde {\rm t}1}>90$ GeV/c2, and $m_{\tilde {\rm b}1}>96$ GeV/c2 for purely left squarks. $m_{\tilde {\rm t}1}>87$ GeV/c2, and $m_{\tilde {\rm b}1}>82$ GeV/c2 independent of the mixing angle.
Journal ArticleDOI
TL;DR: The ATLAS hadronic Tile Calorimeter will undergo major upgrades to the on- and off-detector electronics in preparation for the High Luminosity program of the Large Hadron Collider in 2026, so that the system can cope with the HL-LHC increased radiation levels and out-of-time pileup.
Abstract: The ATLAS hadronic Tile Calorimeter will undergo major upgrades to the on- and off-detector electronics in preparation for the High Luminosity program of the Large Hadron Collider (HL-LHC) in 2026, so that the system can cope with the HL-LHC increased radiation levels and out-of-time pileup The on-detector electronics of the upgraded system will continuously digitize and transmit all photo-multiplier signals to the off-detector systems at a 40 MHz rate The off-detector electronics will store the data in pipeline buffers, produce digital hadronic tower sums for the ATLAS Level-0 trigger system, and read out selected events The modular on-detector electronics feature radiation-tolerant commercial off-the-shelf components and redundant design to minimize single points of failure The timing, control and communication interface with the off-detector electronics is implemented with modern Field Programmable Gate Arrays and high speed fibre optic links running up to 96 Gbps
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Jalal Abdallah, P. Abreu1, Wolfgang Adam2, Petar Adzic  +340 moreInstitutions (42)
TL;DR: The first measurement of the average polarisation P-tau of tau leptons produced in e(+)e(-) annihilation at energies significantly above the Z resonance is presented in this article.

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01 Apr 1988-Nature
TL;DR: In this paper, a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) is presented.
Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

9,929 citations

Journal ArticleDOI
Georges Aad1, T. Abajyan2, Brad Abbott3, Jalal Abdallah4  +2964 moreInstitutions (200)
TL;DR: In this article, a search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9.

9,282 citations

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TL;DR: MadGraph5 aMC@NLO as discussed by the authors is a computer program capable of handling all these computations, including parton-level fixed order, shower-matched, merged, in a unified framework whose defining features are flexibility, high level of parallelisation and human intervention limited to input physics quantities.
Abstract: We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5 aMC@NLO, capable of handling all these computations — parton-level fixed order, shower-matched, merged — in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV e + e − collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

6,509 citations

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TL;DR: The current status of particle dark matter, including experimental evidence and theoretical motivations, including direct and indirect detection techniques, is discussed in this paper. But the authors focus on neutralinos in models of supersymmetry and Kaluza-Klein dark matter in universal extra dimensions.

4,614 citations