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A. F. Kord

Publications and source records attributed to A. F. Kord.

15 recordsLinked to original sources
arXiv2024

The utilization of magneto-hydrodynamics framework in expansion of magnetized viscous conformal flow

The evolution of magnetized quark gluon plasma (QGP) in the framework of magneto-hydrodynamics is the focus of our study. We are investigating the temporal and spatial evolution of QGP using a second order viscous hydrodynamic framework. The fluid is considered to be magnetized and subjected to the influence of a magnetic field that is generated during the early stages of relativistic heavy ion collisions.We assume boost invariance along the beam line, which is represented by the $z$ coordinate, and fluid expansion in the $x$ direction. Additionally, we assume that the magnetic field is perpendicular to the reaction plane, which corresponds to the $y$ direction. The fluid is considered to have infinite electrical conductivity. To analyze this system, we solve the coupled Maxwell and conservation equations. By doing so, we are able to determine the time and space dependence of the energy density, velocity, and magnetic field in the transverse plane of the viscous magnetized hot plasma. Furthermore, we obtain the spectrum of hadrons and compare it with experimental data.

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arXiv2023

Transverse and non-boost longitudinal expansion of (2+1)dimensional relativistic ideal-hydrodynamics flow in heavy ion collisions

This study investigates the evolution of quark gluon plasma (QGP) within a generalized Bjorken flow framework. The medium under consideration is assumed to possess a finite transverse size and to expand both radially and along the beam axis. However, we assume that the boost invariance of longitudinal expansion is broken. To be more specific, we generalize the Bjorken solution to include the acceleration and transverse expansion of the fluid. We analytically study the (2 + 1) dimensional longitudinal acceleration expansion of hot and dense quark matter, applying a perturbation approach to solve the relativistic hydrodynamics equations. This procedure enables us to obtain exact algebraic expressions for fluid velocities and energy densities in both transverse and longitudinal directions. To simplify our calculations, we assume that the fluid is produced in central collisions, and therefore, we consider azimuthal symmetry. We compare the radial velocity and correction energy density with those obtained from the Gubser model. Furthermore, we determine the fluid's acceleration parameter and longitudinal correction energy density, which exhibits a Gaussian distribution.

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arXiv2021

Transverse expansion of (1 + 2) dimensional magneto-hydrodynamics flow with longitudinal boost invariance

In the present work, we investigate the effects of magnetic field on expanding hot and dense nuclear matter as an ideal fluid. We consider QGP, on the particular case of a (1 + 2) dimensional longitudinally boost-invariant fluid expansion, in the background of an inhomogeneous magnetic field that is generated by external sources. We assume the magnetic field points in the direction perpendicular to the reaction plane, follows the power-law decay in proper time, and has two components on the transverse plane. To simplify the calculation, we suppose the investigated fluid has azimuthal symmetry, and magneto-hydrodynamic equations are described in a polar coordinate system on the transverse plane of reaction. Our results depict the space-time evolution of the transverse expansion of the fluid in the presence of an inhomogeneous external magnetic field. Ultimately, we utilize transverse velocity and correction of energy density to estimate the transverse momentum spectrum of final particles that emerge from heavy-ion collisions based on experimental data.

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arXiv2020

Analytical solution of magneto-hydrodynamics with acceleration effects of Bjorken expansion in heavy-ion collisions

In this work, we study the 1+1 longitudinal acceleration expansion of hot and dense quark matter as a conducting relativistic fluid with the electric conductivity $σ$. The plasma has embedded in the presence of electric and magnetic fields which are perpendicular together in the transverse plane. In order to be more realistic, we generalize the Bjorken solution, which includes the acceleration effects on the fluid expansion. We apply a perturbation fashion in initial condition to solve the relativistic magneto-hydrodynamics equations. This procedure leads us to achieve the exact algebraic expressions for both electric and magnetic fields. We also find the effects of the electromagnetic fields on the acceleration of the fluid, and the correction of energy density obtained from the magneto-hydrodynamics solutions.

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arXiv2019

Transverse expansion of hot magnetized Bjorken flow in heavy ion collisions

We argue that the existence of an inhomogeneous external magnetic field can lead to radial flow in transverse plane. Our aim is to show how the introduction of a magnetic field generalizes the Bjorken flow. We investigate the effect of an inhomogeneous weak external magnetic field on the transverse expansion of in-viscid fluid created in high energy nuclear collisions. In order to simplify our calculation and compare with Gubser model, we consider the fluid under investigation to be produced in central collisions, at small impact parameter; azimuthal symmetry has been considered. In our model, we assume an inhomogeneous external magnetic field following the power-law decay in proper time and having radial inhomogeneity perpendicular to the radial velocity of the in-viscid fluid in the transverse plane; then the space time evolution of the transverse expansion of the fluid is obtained. We also show how the existence of an inhomogeneous external magnetic field modifies the energy density. Finally we use the solutions for the transverse velocity and energy density in the presence of a weak magnetic field, to estimate the transverse momentum spectrum of protons and pions emerging from the Magneto-hydrodynamic solutions.

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arXiv2017

Non-relativistic approximate numerical ideal-magneto hydrodynamics of (1+1) D transverse flow in Bjorken scenario

In this study, we investigate the impact of the magnetic field on the evolution of the transverse flow of QGP matter in the magneto-hydrodynamic (MHD) framework. We assume that the magnetic field is perpendicular to the reaction plane and then we solve the coupled Maxwell and conservation equations in (1+1D) transverse flow, within the Bjorken scenario. We consider a QGP with infinite electrical conductivity. First, the magnetic effects on the QGP medium at mid-rapidity are investigated at leading order; then the time and space dependence of the energy density, velocity and magnetic field in the transverse plane of the ideal magnetized hot plasma are obtained.

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arXiv2015

The role of field redefinition on renormalisability of a general $N=\frac{1}{2}$ supersymmetric gauge theories

We investigate some issues on renormalisability of non-anticommutative supersymmetric gauge theory related to field redefinitions. We study one loop corrections to $N=\frac{1}{2}$ supersymmetric $SU(N)\times U(1)$ gauge theory coupled to chiral matter in component formalism, and show the procedure which has been introduced for renormalisation is problematic because some terms which are needed for the renormalisability of theory are missed from the Lagrangian. In order to prove the theory is renormalisable, we redefine the gaugino and the auxiliary fields($λ, \bar F$), which result in a modified form of the Lagrangian in the component formalism. Then, we show the modified Lagrangian has extra terms which are necessary for renormalisability of non-anticommutative supersymmetric gauge field theories. Finally we prove $N = \frac{1}{2}$ supersymmetric gauge theory is renormalisable up to one loop corrections using standard method of renormalisation; besides, it is shown the effective action is gauge invariant.

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arXiv2014

Comments on the role of field redefinition on renormalisation of $N=\frac{1}{2}$ supersymmetric pure gauge theory

We study one loop corrections to $N=\frac{1}{2}$ supersymmetric $SU(N)\times U(1)$ pure gauge theory. We calculate divergent contributions of the 1PI graphs contain the non-anti-commutative parameter $C$ up to one loop corrections. We find the disagreement between component formalism and superspace formalism is because of the field redefinition in component case. We modify gaugino field redefinition and lagrangian. We show extra terms of lagrangian have been generated by $λ$ redefinition and are necessary for the renormalisation of the theory. Finally we prove $N = \frac{1}{2}$ supersymmetric gauge theory is renormalisable up one loop corrections using standard method of renormalisation

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arXiv2004

Snowmass Benchmark Points and Three-Loop Running

We present the full three-loop beta-functions for the MSSM generalised to include additional matter multiplets in 5, 10 representations of SU(5). We analyse in detail the effect of three-loop running on the sparticle spectrum for the MSSM Snowmass Benchmark Points. We also consider the effect on these spectra of additional matter multiplets (the semi-perturbative unification scenario).

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arXiv2004

R-parity Violation and General Soft Supersymmetry Breaking

We consider the most general class possible of soft supersymmetry breaking terms that can be added to the MSSM, with and without R-parity violation, consistent with the sole requirement that no quadratic divergences are induced. We renormalise the resulting theory through one loop and give an example of how a previously ignored term might affect the sparticle spectrum.

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arXiv2003

Three loop soft running, benchmark points and semi-perturbative unification

We consider three-loop $β$-function corrections to the sparticle spectrum in the MSSM, with particular emphasis on Snowmass Benchmark points. The three loop running has little effect on the weakly interacting particle spectrum, but for the squark masses the effect can be comparable to, or greater than, that of two loop running. We extend the analysis to the semi-perturbative unification scenario, where the impact of the three loop corrections becomes even more dramatic.

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