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Fatemeh Taghavi Shahri

Publications and source records attributed to Fatemeh Taghavi Shahri.

6 recordsLinked to original sources

Self-Similar Properties of the Proton Structure at Low x within the \textbf{xFitter} framework

The structure of the proton exhibits Fractal behavior at low \textit{x}, where \textit{x} is the fraction of the proton's momentum carried by the interacting partons. This Fractal behavior is characterized by self-similar properties at different scales and can be quantified using the concept of Fractal dimension. An investigation into the Fractal properties of the proton structure at low \textit{x} is critical for understanding the fundamental properties of the strong force and developing a more comprehensive understanding of the hadron structure. Fractals, characterized by self-similar patterns across scales, demonstrate a direct correlation between their Fractal dimension and entropy, where higher Fractal dimensions correspond to increased informational content. Furthermore, it is essential for designing high-energy physics experiments and developing more accurate models of subatomic particle interactions. This paper has a fresh look at the self-similar properties of the proton structure at low \textit{x}. Our study involves the use of the \textbf{xFitter} framework to parameterize the proton structure functions with a Fractal formalism at low \textit{x}. We also examine how the inclusion of new data affects the results of our analysis.

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A comparative study of different approaches for heavy quark energy loss, based on the latest experimental data

This paper presents a comparative analysis of three distinct methods used to calculate the collisional energy loss of heavy quarks in Quark-Gluon Plasma. The study focuses on the calculation of the nuclear suppression factor of charm quarks in Pb-Pb collisions at $\sqrt{S_{NN}} = 5.02$ TeV. All three models are examined using the same numerical evolution based on the well-known Fokker-Planck equation by considering critical phenomena like a non-equilibrium state at the onset of heavy ion collision. The outcomes of each approach are compared with the latest data from ALICE and ATLAS experiments spanning from 2018 to 2022. This study aims to compare the degree of agreement between each approach and recently obtained experimental data, in the intermediate and high $P_T$ regions.

hep-ph↗

Analytical solutions of the QCD$\otimes$QED DGLAP evolution equations based on the Mellin transform technique in NLO approximation

In this paper we present a new and efficient analytical solutions for evolving the QED$\otimes$QCD DGLAP evolution equations in mellin space and obtain the parton distribution functions (PDFs) in perturbative QCD including the QED corrections. The validity of our analytical solutions, which have done in the next to leading order QCD and the leading order QED approximations, are checked with the initial parton distributions from newly released CT14QED global analysis code (Phys. Rev.D93,114015(2016)). The evolved parton distributions are in good agreement with CT14QED code and also with those from APFEL (Computer Physics Communications 185, 1647 (2014)) program.

hep-ph↗

Parton distribution functions with QED corrections in the valon model

Parton distribution functions (PDFs) with QED corrections extracted from the QED$\otimes$QCD DGLAP evolution equations in the framework of "valon" model. Our results for the PDFs with QED corrections in this phenomenological model are in good agreement with the newly related CT14QED global fit code [Phys. Rev. D93, 114015 (2016)] and APFEL (NNPDF2.3QED) [Computer Physics Communications 185, 1647 (2014)] program in a wide range of $x=[10^{-5}, 1]$ and $Q^2=[0.283, 10^8] \, {\rm GeV}^2$. The model calculations agree rather well with those codes. We also proposed the new method for studying the symmetry breaking of the sea quarks distribution functions inside proton. Then these PDFs set can be used to explore the proton-proton scattering at the LHC era.

hep-ph↗

Evolution of heavy quark distribution function in quark-gluon plasma: using the Iterative Laplace Transform Method

The "Iterative Laplace Transform Method" is used to solve the Fokker-Planck equation for finding the time evolution of the heavy quarks distribution functions such as charm and bottom in quark gluon plasma. These solutions will lead us to calculation of nuclear suppression factor RAA. The results have good agreement with available experiment data from the PHENIX collaboration.

hep-ph↗

Non-Singlet spin structure function in the valon model and low x scaling behavior of $g_{1}^{NS}$ and $g_1^p$

A next-to-leading order QCD calculation of non-singlet spin structure function, $g_{1}^{NS} $ is presented within the valon representation of Hadrons. In the valon model, it is assumed that a nucleon is composed of three dressed valence quarks: the valons which have their own internal structure, the valence quark with its associated sea quarks and gluons. The results are in good agreement with all available data from SMC, E143, HERMES and with the newly released data from COMPASS experiments. It appears that the small x tail of $g_{1}^{NS}$ can be described by a single Regge-type exchange. The relevant parameter of this exchange is given. Finally we show that the polarized proton structure function has a scaling behavior at small x. The relevant parameters of this behavior are given too.

hep-ph↗