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: In this paper, the mean and densities of all-particle and chargedparticle multiplicity were measured with the ATLAS detector at the LHC, based on of proton-proton collision data collected at a centre-of-mass energy of 7.
Abstract: Distributions sensitive to the underlying event in QCD jet events have been measured with the ATLAS detector at the LHC, based on of proton-proton collision data collected at a centre-of-mass energy of 7 . Charged-particle mean and densities of all-particle and charged-particle multiplicity and have been measured in regions azimuthally transverse to the hardest jet in each event. These are presented both as one-dimensional distributions and with their mean values as functions of the leading-jet transverse momentum from 20 to 800 . The correlation of charged-particle mean with charged-particle multiplicity is also studied, and the densities include the forward rapidity region; these features provide extra data constraints for Monte Carlo modelling of colour reconnection and beam-remnant effects respectively. For the first time, underlying event observables have been computed separately for inclusive jet and exclusive dijet event selections, allowing more detailed study of the interplay of multiple partonic scattering and QCD radiation contributions to the underlying event. Comparisons to the predictions of different Monte Carlo models show a need for further model tuning, but the standard approach is found to generally reproduce the features of the underlying event in both types of event selection.
32 citations
TL;DR: In this article, the strong coupling alpha(s) was determined from data in e(+)e(-) collisions between 183 and 207 GeV. The strong coupling was extracted in O(alpha(s)(2)), NLLA and matched O(α(s((2))+NLLA theory.
Abstract: Hadronic event shape distributions are determined from data in e(+)e(-) collisions between 183 and 207 GeV. From these the strong coupling alpha(s) is extracted in O(alpha(s)(2)), NLLA and matched O(alpha(s)(2))+ NLLA theory. Hadronisation corrections evaluated with fragmentation model generators as well as an analytical power ansatz are applied. Comparing these measurements to those obtained at and around M-Z allows a combined measurement of alpha(s) from all DELPHI data and a test of the energy dependence of the strong coupling.
32 citations
TL;DR: In this paper, double-differential three-jet production cross-sections are measured in proton-proton collisions at a center-of-mass energy of root s = 7 TeV using the ATLAS detector at the large hadron collider.
Abstract: Double-differential three-jet production cross-sections are measured in proton-proton collisions at a centre-of-mass energy of root s = 7 TeV using the ATLAS detector at the large hadron collider. ...
32 citations
Aix-Marseille University1, University of Oklahoma2, Academia Sinica3, Azerbaijan National Academy of Sciences4, University of Amsterdam5, Michigan State University6, University of Toronto7, Tel Aviv University8, Technion – Israel Institute of Technology9, University of Oregon10, Stockholm University11, King's College London12, International Centre for Theoretical Physics13, AGH University of Science and Technology14, Brookhaven National Laboratory15, Northern Illinois University16, Ludwig Maximilian University of Munich17, Rutherford Appleton Laboratory18, University of Liverpool19, University of Belgrade20, University of Göttingen21, University of Granada22, Boston University23, Joint Institute for Nuclear Research24, University of Rome Tor Vergata25, Lund University26, Russian Academy of Sciences27, University of Bologna28, University of Victoria29, University of Grenoble30, National University of La Plata31, CERN32, National Technical University of Athens33, University of Chicago34, Columbia University35, University of Sussex36, University of Copenhagen37, Queen Mary University of London38, Spanish National Research Council39, Lawrence Berkeley National Laboratory40, KEK41, Federal University of Rio de Janeiro42, Brandeis University43, University of Michigan44, University of Coimbra45, University of Lisbon46, University of Freiburg47, University of Sheffield48, University of Geneva49, Heidelberg University50, University of Milan51, National and Kapodistrian University of Athens52, Dresden University of Technology53, Novosibirsk State University54, Budker Institute of Nuclear Physics55, Autonomous University of Barcelona56, University of Pisa57, National Research Nuclear University MEPhI58
TL;DR: A measurement of the B-s(0) decay parameters in the J/psi/phi channel using an integrated luminosity of 14.3 fb(-1) collected by the ATLAS detector from 8TeV pp collisions at the LHC is presented in this article.
Abstract: A measurement of the B-s(0) decay parameters in the B-s(0) -> J/psi/phi channel using an integrated luminosity of 14.3 fb(-1) collected by the ATLAS detector from 8TeV pp collisions at the LHC is presented. The measured parameters include the CP-violating phase phi(s), the decay width Gamma(s) and the width di ff erence between the mass eigenstates Delta Gamma(s). The values measured for the physical parameters are statistically combined with those from 4.9 fb-1 of 7TeV data, leading to the following: phi(s) = -0.090 +/- 0.078 (stat.) +/- 0.041 (syst.) rad Delta Gamma s = 0.085 +/- 0.011 (stat.) +/- 0.007 (syst.) ps(-1) Gamma(s) = 0.675 +/- 0.003 (stat.) +/- 0.003 (syst:) ps(-1). In the analysis the parameter Delta Gamma(s) is constrained to be positive. Results for phi(s) and Delta Gamma(s) are also presented as 68% and 95% likelihood contours in the phi(s)-Delta Gamma(s) plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions.
32 citations
TL;DR: In this paper, a study of the event shapes of different types of gammagamma processes in the PYTHIA program was conducted, and it was shown that (74+/-22) % of the observed J/psi events are due to resolved photons.
32 citations
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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