460 research outputs found

    Two-particle correlation studies in heavy ion collisions at the Large Hadron Collider

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    Results on two-particle angular correlations in pPb at [square root sNN] =5.02 TeV and PbPb collisions at [square root sNN] =2.76 TeV are reported. The long-range correlations in pseudorapidity (‚Äúridge\u27\u27) has been seen in various systems, including PbPb, pPb and pp systems. In this thesis, two-particle correlations in pPb collisions at nucleon-nucleon center-of-mass energy of 5.02 TeV are studied as a function of the pseudorapidity separation (őĒ ő∑) of the particle pair at small azimuthal angle separation (|őĒ&phis;| \u3c ŌÄ/3). The correlations are decomposed into a jet component that dominates the short-range correlations (|őĒő∑| \u3c 1), and a component that persists at large őĒő∑, which is the ridge. The ridge may be associated with collective behavior of the produced system, well described by hydrodynamics. The azimuthal correlations, after subtraction of the jet component, are characterized by the V 2 and V3 coefficient. The single-particle anisotropy parameters v2 and v 3 are extracted and normalized by their mid-rapidity value. The normalized v2(ő∑cm)/v 2(ő∑cm=-0.465) distribution as a function of the center-of-mass pseudorapidity ő∑cm is found to be asymmetric about ő∑cm = 0, with smaller values observed at forward proton direction pseudorapidity, and smaller value at backward Pb direction, but the decreasing trend towards the two sides is different. The normalized v3(ő∑ cm)/v3(ő∑ cm=-0.465) distribution has no significant pseudorapidity dependence within the statistical uncertainties. The underlying physics for the ő∑ dependence of the v2 parameter is under extensive research at the time of this thesis writing. The two-particle correlation method is widely used also in jet-like correlation studies. The jet axis direction can be identified effectively by a high pT particle. The away-side partner jet is quenched in heavy ion collisions due to medium interactions. The biggest challenge in jet correlation studies is the subtraction of the large underlying anisotropy flow backgroud. In previous studies, the flow background is calculated from the measured Fourier coefficients, which results in large uncertainties. In this thesis, the away-side jet shape of PbPb collisions at [square root sNN] =2.76 TeV is studied utilizing a novel method of subtracting flow background using the data itself. The away-side is enhanced by a relatively large recoil transverse momentum in a given ő∑ range. The two-particle correlation function is constructed from different ő∑ regions, one is close and the other far away from the away-side jet. These two ő∑ regions are symmetric about ő∑=0, so the flow background is the same. The correlation function difference between these two regions, therefore, measures the away-side jet shape. The jet width is studied as a function of multiplicity and pT. It is found that the jet width increases with multiplicity, indicating jet broadening in medium

    Analysis on Port and Maritime Transport System Researches

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    This paper examines the past and current research in the container port and maritime field. Using rigorous bibliometric analysis, the paper identifies the core authors/affiliations, their rankings, and collaboration patterns. The analysis of the paper will enable new researchers to quickly build an understanding of the container port and maritime field by reading core authors’ papers published in specific journals. Document type: Articl

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function √į√į¬•with constraints√į √į √į¬• ¬• √įand√į¬ī√į¬• = √į. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Differential cross section measurements for the production of a W boson in association with jets in proton‚Äďproton collisions at ‚ąös = 7 TeV