Author
Jalal Abdallah
Other affiliations: Autonomous University of Barcelona, Spanish National Research Council, University of Pennsylvania ...read more
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.
Topics: Large Hadron Collider, Higgs boson, Lepton, Boson, Pair production
Papers published on a yearly basis
Papers
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TL;DR: The track reconstruction efficiency in the cores of jets with transverse momenta between 200 and 1600 GeV is quantified using a novel, data-driven, method and the impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed.
Abstract: With the increase in energy of the Large Hadron Collider to a centre-of-mass energy of 13 TeV for Run 2, e vents with dense environments, such as in the cores of high-energy jets, became a focus for new physics searches as well as measurements of the Standard Model. These environments are characterized by charged-particle separations of the order of the tracking detectors sensor granularity. Basic track quantities are compared between 3.2 fb - 1 of data collected by the ATLAS experiment and simulation of proton–proton collisions producing high-transverse-momentum jets at a centre-of-mass energy of 13 TeV. The impact of charged-particle separations and multiplicities on the track reconstruction performance is discussed. The track reconstruction efficiency in the cores of jets with transverse momenta between 200 and 1600 GeV is quantified using a novel, data-driven, method. The method uses the energy loss, dE/dx, to identify pixel clusters originating from two charged particles. Of the charged particles creating these clusters, the measured fraction that fail to be reconstructed is 0.061±0.006(stat.)±0.014(syst.) and 0.093±0.017(stat.)±0.021(syst.) for jet transverse momenta of 200–400 GeV and 1400–1600 GeV , respectively.
135 citations
TL;DR: In this article, the authors measured the production of a W boson in association with a charm quark in pp collisions at root s=7 TeV with the ATLAS detector.
Abstract: Measurement of the production of a W boson in association with a charm quark in pp collisions at root s=7 TeV with the ATLAS detector
134 citations
TL;DR: The search for the Higgs boson decays to a photon and a Z boson in pp collisions at root s=7 and 8 TeV with the ATLAS detector as discussed by the authors.
133 citations
Aix-Marseille University1, University of Oklahoma2, University of Iowa3, Azerbaijan National Academy of Sciences4, Université Paris-Saclay5, University of Amsterdam6, Michigan State University7, University of California, Santa Cruz8, University of Sussex9, Tel Aviv University10, Technion – Israel Institute of Technology11, University of Oregon12, Stockholm University13, International Centre for Theoretical Physics14, AGH University of Science and Technology15, Brookhaven National Laboratory16, Northern Illinois University17, Ludwig Maximilian University of Munich18, Rutherford Appleton Laboratory19, University of Liverpool20, University of Belgrade21, University of Göttingen22, University of Granada23, Boston University24, Joint Institute for Nuclear Research25, University of Rome Tor Vergata26, Lund University27, Russian Academy of Sciences28, University of Bologna29, University of Victoria30, University of Grenoble31, National University of La Plata32, CERN33, National Technical University of Athens34, University of Chicago35, Columbia University36, University of Birmingham37, University of Copenhagen38, University of Washington39, Spanish National Research Council40, Lawrence Berkeley National Laboratory41, KEK42, Federal University of Rio de Janeiro43, Brandeis University44, University of Michigan45, University of Coimbra46, University of Lisbon47, University of Sheffield48, University of Geneva49, University of Texas at Austin50, Heidelberg University51, University of Milan52, National and Kapodistrian University of Athens53, Dresden University of Technology54, Budker Institute of Nuclear Physics55, IFAE56, University of Pisa57, National Research Nuclear University MEPhI58, Slovak Academy of Sciences59
TL;DR: In this paper, a direct search for lepton flavour violation in decays of the Higgs and Z bosons with the ATLAS detector at the LHC is presented, and upper limits on the lepton-flavour-violating branching ratios are set at the 95[Formula: see text] confidence level.
Abstract: Direct searches for lepton flavour violation in decays of the Higgs and Z bosons with the ATLAS detector at the LHC are presented. The following three decays are considered: [Formula: see text], [Formula: see text], and [Formula: see text]. The searches are based on the data sample of proton-proton collisions collected by the ATLAS detector corresponding to an integrated luminosity of 20.3 [Formula: see text] at a centre-of-mass energy of [Formula: see text] TeV. No significant excess is observed, and upper limits on the lepton-flavour-violating branching ratios are set at the 95[Formula: see text] confidence level: Br[Formula: see text], Br[Formula: see text], and Br[Formula: see text].
132 citations
TL;DR: Results of a search for the electroweak associated production of chargino and next-to-lightest neutralinos, pairs of charginos or pairs of tau sleptons are presented, characterised by final states with at least two hadronically decaying tau leptons, missing transverse momentum and low jet activity.
Abstract: Results of a search for the electroweak associated production of charginos and next-to-lightest neutralinos, pairs of charginos or pairs of tau sleptons are presented. These processes are characterised by final states with at least two hadronically decaying tau leptons, missing transverse momentum and low jet activity. The analysis is based on an integrated luminosity of 20.3 fb(-1) of proton-proton collisions at root s = 8 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excess is observed with respect to the predictions from Standard Model processes. Limits are set at 95% confidence level on the masses of the lighter chargino and next-to-lightest neutralino for various hypotheses for the lightest neutralino mass in simplified models. In the scenario of direct production of chargino pairs, with each chargino decaying into the lightest neutralino via an intermediate tau slepton, chargino masses up to 345 GeV are excluded for a massless lightest neutralino. For associated production of mass-degenerate charginos and next-to-lightest neutralinos, both decaying into the lightest neutralino via an intermediate tau slepton, masses up to 410 GeV are excluded for a massless lightest neutralino.
131 citations
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Journal Article•
28,685 citations
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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
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
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
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