arXiv subjects

Mahmoud Hanafy

Publications and source records attributed to Mahmoud Hanafy.

11 recordsLinked to original sources

arXiv2025

Derivation of Meson Masses in SU(3) and SU(4) Extended Linear-Sigma Model at Finite Temperature

The present study focuses on the mesonic potential contributions to the Lagrangian of the extended linear-sigma model (eLSM) for scalar and pseudoscalar meson fields across various quark flavors. The present study focuses on the low-energy phenomenology associated with quantum chromodynamics (QCD), where mesons and their interactions serve as the pertinent degrees of freedom, rather than the fundamental constituents of quarks and gluons. Given that SU(4) configurations are completely based on SU(3) configurations, the possible relationships between meson states in SU(3) and those in SU(4) are explored at finite temperature. Meson states, which are defined by distinct chiral properties, are grouped according to their orbital angular momentum $J$, parity $P$, and charge conjugation $C$. Consequently, this organization yields scalar mesons with quantum numbers $J^{PC}=0^{++}$, pseudoscalar mesons with $J^{PC}=0^{-+}$, vector mesons with $J^{PC}=1^{--}$, and axialvector mesons with $J^{PC}=1^{++}$. We accomplished the derivation of analytical expressions for a total of seventeen noncharmed meson states and twenty-nine charmed meson states so that an analytical comparison of the noncharmed and charmed meson states at different temperatures becomes feasible and the contributions SU(3) and SU(4) configurations can be estimated, analytically.

hep-ph↗

arXiv2022

Rapidity Distribution within Landau hydrodynamical model and EPOS event-generator at RHIC Energies

The rapidity distribution of well-defined particles pions, Kaons, protons and their antiparticles measured in the BRAHMS experiment (Au+Au collisions), at $\sqrt{s_{NN}}$ = $62.4$ and $200$ GeV, are compared with huge statistical ensembles of 100, 000 events deduced from the Cosmic Ray MonteCarlo (CRMC) EPOS event-generator. All these data are then compared to the Landau hydrodynamical model. We conclude that the Landau hydrodynamical model is capable of describing both experimental data and EPOS $1.99$ event-generator results, and that they are in good agreement.

hep-ph↗

arXiv2022

Particle ratios with in Hadron Resonance Gas (HRG) and Artificial Neural Network (ANN) models

Comparison between various particle ratios such as $K^-/K^+$, $π^-/π^+$, $\bar{p}/p$, $\barΛ/Λ$, $\barΣ/Σ$, $ \barΩ/Ω$, $K^+/π^+$, $K^-/π^-$, $\bar{p}/π^-$, $p/π^-$, $Λ/π^-$, and $Ω/π^-$ calculated using the HRG model with the results estimated from simulation and training of the ANN model in the presence of different experiments measurements such as AGS, SPS, RHIC and LHC energies is done. The success of ANN simulation model to describe the results from both phonological (HRG) model and experimental data will encourage to use it in various predictions for other particle ratios in regions where is no experiments.

hep-ph↗

arXiv2021

Strangeness Enhancement at LHC Energies using the thermal model and EPOSLHC event-generator

The strangeness enhancement signature of QGP formation at LHC energies is carefully tackled in the present study. Based on HRG, the particle ratios of mainly strange and multi-strange particles are studied at energies from lower $\sqrt{s}\sim $ 0.001 up to 13 TeV. The strangeness enhancement clearly appeared at more higher energies, and the ratios are confronted to the available experimental data. The particle ratios are also studied using the Cosmic Ray Monte Carlo (CRMC) interface model with its two different event generators namely; EPOS $1.99$ and EPOSlhc which show a good agreement with the model calculations at the whole range of the energy. We utilize to produce some ratios. EPOS $1.99$ is used to estimate particle ratios at lower energies from AGS up to the Relativistic Heavy Ion Collider (RHIC) while EPOSlhc is used at LHC energies. The production of kaons and lambda particles is studied in terms of the mean multiplicity in p-p collisions at energies ranging from 4 - 26 GeV. We find that both HRG model and the used event generators, EPOS $1.99$ and EPOSlhc, can describe the particle ratios very well. Additionally, the freeze-out parameters are estimated for different collision systems, such as p-p and Pb-Pb, at LHC energies using both models.

hep-ph↗

arXiv2021

Entropy per rapidity in Pb-Pb central collisions using Thermal and Artificial neural network(ANN) models at LHC energies

The entropy per rapidity $d S/d y$ produced in central Pb-Pb ultra-relativistic nuclear collisions at LHC energies is calculated using experimentally observed identified particle spectra and source radii estimated from Hanbury Brown-Twiss (HBT) for particles, $π$, $k$, $p$, $Λ$, $Ω$, and $\barΣ$, and $π$, $k$, $p$, $Λ$ and $K_s^0$ at $ \sqrt{s}$ $=2.76$ and $5.02$ TeV, respectively. Artificial neural network (ANN) simulation model is used to estimate the entropy per rapidity $d S/d y$ at the considered energies. The simulation results are compared with equivalent experimental data, and good agreement is achieved. A mathematical equation describes experimental data is obtained. Extrapolating the transverse momentum spectra at $p_T$ $=0$ is required to calculate $d S/d y$ thus we use two different fitting functions, Tsallis distribution and the Hadron Resonance Gas (HRG) model. The success of ANN model to describe the experimental measurements will imply further prediction for the entropy per rapidity in the absence of the experiment.

hep-ph↗

arXiv2021

Particles Multiplicity Based on Rapidity in Landau and Artificial Neural Network(ANN) Models

ANN model is used to estimate the multiplicity per rapidity for charged pions and kaons observed in various high-energy experiments from central Au+Au collisions with energies ranging from 2-200 GeV, and then compared to available experimental data, including RHIC-BRAHMS, and the future facilities at NICA and FAIR. We also used Landau hydrodynamical approach, which has a better describtion for the evolution of hot and dense matter produced in ultra-relativistic heavy-ion collisions. The approach is fitted to both results estimated from experiment and ANN simulation. We noticed that the Landau model accurately reproduces the entire range of multiplicity per rapidity for all created particles at all energies. Also ANN model can reproduce the multiplicity per rapidity very well for all considered particles.

hep-ph↗

arXiv2021

Particle Ratios within a statistically corrected hadron resonance gas model and EPOS event-generator at AGS, SPS, RHIC and LHC Energies

We further investigate the applicability of our previously suggested quantum-mechanically correlated statistical hadron gas model (HRG) to the ideal hadron resonance gas model (IHRG), which is inspired by a Beth-Uhlenbeck corrected form of the equation of state (EoS). We compute the ratios of several particle yields, both equal-mass pairs ($\bar{p} / p$, $K^-/ K^+$, $\pi^-/ \pi^+$, $\bar{\Lambda}/ \Lambda$, $\bar{\Sigma}/ \Sigma$, $\bar{\Omega}/ \Omega$) and unequal-mass pairs ($p/ \pi^+$, $k^+/ \pi^+$, $k^-/ \pi^-$, $\Lambda/ \pi^-$, $\bar{p}/ \pi^-$, $\Omega/\pi^-$) and investigate how these ratios change with the center-of-mass energy. Next, we present a comparative analysis of the outputs of our suggested HRG model and the IHRG model, Cosmic Ray Monte Carlo (CRMC) EPOS $1.99$ simulations, and experimental data from ALICE, SPS, AGS, and RHIC. When compared to the other models taken into consideration, our HRG model typically shows very close agreement with the experimental results. The proton anomaly reported at top RHIC and LHC energies may be addressed by our new HRG model, which notably exhibits a strong alignment with experimental data for $\bar{p}/ \pi^-$ and $p/ \pi^+$ ratios. However, both our HRG model and the IHRG model seem to significantly underestimate some experimental data for ratios involving hadron couples with uneven mass and (multi)strange content, such as $\Lambda/ \pi^-$ and $\Omega/ \pi^-$. This emphasizes the necessity of additional research to determine whether thermal hadron gas models are appropriate and stresses the significance of any necessary adjustments to improve their correctness.

hep-ph↗

arXiv2020

An approach of statistical corrections to interactions in hadron resonance gas

We propose a new model for hadrons with quantum mechanical attractive and repulsive interactions sensitive to some spatial correlation length parameter inspired by Beth-Uhlenbeck quantum mechanical non-ideal gas model \cite{uhlenbeck1937quantum}. We confront the thermodynamics calculated using our model with a corresponding recent lattice data at four different values of the baryon chemical potential, $μ_{\mathtt{b}}= 0, 170, 340, 425~$MeV over temperatures ranging from $130$ MeV to $200~$MeV and for five values for the correlation length ranging from $0$ to $0.2~$fm. For equilibrium temperatures up to the vicinity of the chiral phase transition temperature $\simeq 160~$MeV, a decent fitting between the model and the lattice data is observed for different values of $r$, especially at $(μ_{\mathtt{b}}, r) = (170,0.05), (340,0.1)$, and $(340,0.15)$, where $μ_{\mathtt{b}}$ is in MeV and $r$ is in fm. For vanishing chemical potential, the uncorrelated model ($r=0$), which corresponds to ideal hadron resonance gas model seems to offer the best fit. The quantum hadron correlations seem to be more probable at non-vanishing chemical potentials, especially within the range $μ_{\mathtt{b}}\in [170, 340~$MeV$]$.

hep-ph↗

arXiv2019

Multiplicity per rapidity in Carruthers and hadron resonance gas approaches

The multiplicity per rapidity of the well-identified particles $π^{-}$, $π^{+}$, $k^{-}$, $k^{+}$, $\bar{p}$, $p$, and $p-\bar{p}$ measured in different high-energy experiments, at energies ranging from $6.3$ to $5500~$GeV, are successfully compared with the Cosmic Ray Monte Carlo (CRMC) event generator. For these rapidity distributions, we introduce a theoretical approach based on fluctuations and correlations (Carruthers) and another one based on statistical thermal assumptions (hadron resonance gas model). Both approaches are fitted to the two sets of results deduced from experiments and simulations. We found that the Carruthers approach reproduces well the full range of multiplicity per rapidity for all produced particles, at the various energies, while the HRG approach fairly describes the results within a narrower rapidity-range. While the Carruthers approach seems to match well with the Gaussian normal distribution, ingredients such as flow and interactions should be first incorporated in the HRG approach.

hep-ph↗

arXiv2019

Particle Ratios within EPOS, UrQMD and Thermal Models at AGS, SPS and RHIC Energies

The particle ratios $k^+/π^+$, $π^-/K^-$, $\bar{p}/π^-$, $Λ/π^-$, $Ω/π^-$, $p/π^+$, $π^-/π^+$, $K^-/K^+$, $\bar{p}/p$, $\barΛ/Λ$, $\barΣ/Σ$, $ \barΩ/Ω$ measured at AGS, SPS and RHIC energies are compared with large statistical ensembles of $100,000$ events deduced from the CRMC EPOS $1.99$ and the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) hybrid model. In the UrQMD hybrid model two types of phase transitions are taken into account. All these are then confronted to the Hadron Resonance Gas Model. The two types of phase transitions are apparently indistinguishable. Apart from $k^+/π^+$, $k^-/π^-$, $Ω/π^-$, $\bar{p}/π^+$, and $\barΩ/Ω$, the UrQMD hybrid model agrees well with the CRMC EPOS $1.99$. Also, we conclude that the CRMC EPOS $1.99$ seems to largely underestimate $k^+/π^+$, $k^-/π^-$, $Ω/π^-$, and $\bar{p}/π^+$.

hep-ph↗

arXiv2016

Particle production and chemical freezeout from the hybrid UrQMD approach at NICA energies

The energy dependence of various particle ratios is calculated within the Ultra-Relativistic Quantum Molecular Dynamics approach and compared with the hadron resonance gas (HRG) model and measurements from various experiments, including RHIC-BES, SPS and AGS. It is found that the UrQMD particle ratios agree well with the experimental results at the RHIC-BES energies. Thus, we have utilized UrQMD in simulating particle ratios at other beam energies down to 3 GeV, which will be accessed at NICA and FAIR future facilities. We observe that the particle ratios for crossover and first-order phase transition, implemented in the hybrid UrQMD v3.4, are nearly indistinguishable, especially at low energies (at large baryon chemical potentials or high density).

nucl-th↗