Papers by wan ahmad tajuddin wan abdullah
Journal of High Energy Physics, 2021
Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-mul... more Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity ep scattering at a centre-of-mass energy $$ \sqrt{s} $$ s = 318 GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities Nch ≥ 20 are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations ...
Physical Review Letters, 2012
Nuclear Physics A, 2021
Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynam... more Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei high-energy collisions. Although the experimental signatures marked a paradigm shift away from expectations of a weakly coupled QGP, a challenge remains as to how the locally deconfined state with a lifetime of a few fm can be resolved. The only colored particle that decays mostly within the QGP is the top quark. Here we demonstrate, for the first time, that top quark decay products are identified, irrespective of whether interacting with the medium (bottom quarks) or not (leptonically decaying W bosons). Using 1.7 ± 0.1 nb −1 of lead-lead (A = 208) collision data recorded by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top quark pair (tt) production. Dilepton final states are selected, and the cross section (σ tt) is measured from a likelihood fit to a multivariate discriminator using lepton kinematic variables. The σ tt measurement is additionally performed considering the jets originating from the hadronization of bottom quarks, which improve the sensitivity to the tt signal process. After background subtraction and analysis corrections, the measured σ tt is 2.56 ± 0.82 (tot) and 2.02 ± 0.69 (tot) μb in the two cases, respectively, consistent with predictions from perturbative QCD.
Physical Review Letters, 2020
The Deviants' Dilemma is a two-person game with the individual gain conflicting with the cho... more The Deviants' Dilemma is a two-person game with the individual gain conflicting with the choice for global good. Evolutionary considerations yield fixed point attractors, with the phenomena of exclusion potentially playing an important role when current opponent information is available. We carry out computer simulations which substantiates and illuminates theoretical claims, and brings to light the pertinance of the choice between deterministic and stochastic dynamics, and the conjecture of 'ergodicity spread'.
Journal of Earth System Science, 2010
The objective of this paper is to investigate the applicability of artificial neural networks in ... more The objective of this paper is to investigate the applicability of artificial neural networks in inverting quasi-3D DC resistivity imaging data. An electrical resistivity imaging survey was carried out along seven parallel lines using a dipole-dipole array to confirm the validation of the results of an inversion using an artificial neural network technique. The model used to produce synthetic data to train the artificial neural network was a homogeneous medium of 100 Ωm resistivity with an embedded anomalous body of 1000 Ωm resistivity. The network was trained using 21 datasets (comprising 12159 data points) and tested on another 11 synthetic datasets (comprising 6369 data points) and on real field data. Another 24 test datasets (comprising 13896 data points) consisting of different resistivities for the background and the anomalous bodies were used in order to test the interpolation and extrapolation of network properties. Different learning paradigms were tried in the training process of the neural network, with the resilient propagation paradigm being the most efficient. The number of nodes, hidden layers, and efficient values for learning rate and momentum coefficient have been studied. Although a significant correlation between results of the neural network and the conventional robust inversion technique was found, the ANN results show more details of the subsurface structure, and the RMS misfits for the results of the neural network are less than seen with conventional methods. The interpreted results show that the trained network was able to invert quasi-3D electrical resistivity imaging data obtained by dipole-dipole configuration both rapidly and accurately.
Nucleosides, Nucleotides and Nucleic Acids, 2011
This article may be used for research, teaching and private study purposes. Any substantial or sy... more This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, redistribution , reselling , loan, sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
International journal of intelligent systems, Jan 1, 1992
Arxiv preprint arXiv:0804.4075, Jan 1, 2008
Arxiv preprint arXiv:0805.0197, Jan 1, 2008
Frontiers in Quantum Physics, Jan 1, 1998
Title: Some New Developments in Structural Theory. Authors: Yaacob, Karim B.; Abdullah, WanAhmad ... more Title: Some New Developments in Structural Theory. Authors: Yaacob, Karim B.; Abdullah, WanAhmad Tajuddin Wan. Publication: Frontiers in Quantum Physics. Edited by SC Lim, R. Abd-Shukor, and KH Kwek. Published by Springer-Verlag, Singapore., p.343. ...
Proceedings of the 2nd IMT-GT …, Jan 1, 2006
… dynamics of economic interaction: essays in …, Jan 1, 2004
AIP Conference …, Jan 1, 2010
... A High‐Energy Electron‐Proton Collision Calorimeter. [AIP Conference Proceedings 1202, 131 (2... more ... A High‐Energy Electron‐Proton Collision Calorimeter. [AIP Conference Proceedings 1202, 131 (2010)]. Faridah Mohamad Idris, Wan Ahmad Tajuddin Wan Abdullah, Zainol Abidin Ibrahim, Burhanuddin Kamaluddin. Abstract. ...
Current Issues of Physics in Malaysia, Jan 1, 2008
We review experiments colliding electtons(/positrons) on protons at high energies at HERA, focusi... more We review experiments colliding electtons(/positrons) on protons at high energies at HERA, focusing on the ZEUS experiment,. We describe the ZEUS detector, including its data acquisition system, and look at a specific part, namely the electronic system for its calorimeter ...
Arxiv preprint arXiv:0804.4071, Jan 1, 2008
Computing
Neural networks are becoming very popular with data mining practitioners because they have proven... more Neural networks are becoming very popular with data mining practitioners because they have proven through comparison their predictive power with statistical techniques using real data sets. Based on this idea, we will present a method for inducing logical rules from empirical data—Reverse Analysis. When the values of the connections of a neural network resulting from Hebbian learning for the data
Frontiers in Quantum Physics, Jan 1, 1998
Title: Neural Networks in Quantum Gravity. Authors: Fares, Hammoudi; Abdullah, Wan AhmadTajuddin ... more Title: Neural Networks in Quantum Gravity. Authors: Fares, Hammoudi; Abdullah, Wan AhmadTajuddin Wan. Publication: Frontiers in Quantum Physics. Edited by SC Lim, R. Abd-Shukor, and KH Kwek. Published by Springer-Verlag, Singapore., p.319. Publication Date: 00/1998 ...
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Papers by wan ahmad tajuddin wan abdullah