arXiv subjects

Muhammad Maher

Publications and source records attributed to Muhammad Maher.

7 recordsLinked to original sources

arXiv2021

Minimal length discretization and properties of modified metric tensor and geodesics

We argue that the minimal length discretization generalizing the Heisenberg uncertainty principle, in which the gravitational impacts on the non--commutation relations are thoughtfully taken into account, radically modifies the spacetime geometry. The resulting metric tensor and geodesic equation combine the general relativity terms with additional terms depending on higher--order derivatives. Suggesting solutions for the modified geodesics, for instance, isn't a trivial task. We discuss on the properties of the resulting metric tensor, line element, and geodesic equation.

physics.gen-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, $\mu_{\mathtt{b}}= 0, 170, 340, 425~$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 $(\mu_{\mathtt{b}}, r) = (170,0.05), (340,0.1)$, and $(340,0.15)$, where $\mu_{\mathtt{b}}$ 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 $\mu_{\mathtt{b}}\in [170, 340~$MeV$]$.

hep-ph↗

arXiv2019

Deconfinement and freezeout boundaries in equilibrium thermal models

In different approaches, the temperature-baryon density plane of QCD matter is studied for deconfinement and chemical freezeout boundaries. Results from various heavy-ion experiments are compared with the recent lattice simulations, the effective QCD-like Polyakov linear-sigma model, and the equilibrium thermal models. Along the entire freezeout boundary, there is an excellent agreement between the thermal model calculations and the experiments. Also, the thermal model calculations agree well with the estimations deduced from the Polyakov linear-sigma model (PLSM). At low baryonic density or high energies, both deconfinement and chemical freezeout boundaries are likely coincident and therefore the agreement with the lattice simulations becomes excellent as well, while at large baryonic density, the two boundaries become distinguishable forming a phase where hadrons and quark-gluon plasma likely coexist.

hep-ph↗

arXiv2019

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

The particle ratios $k^+/\pi^+$, $\pi^-/K^-$, $\bar{p}/\pi^-$, $\Lambda/\pi^-$, $\Omega/\pi^-$, $p/\pi^+$, $\pi^-/\pi^+$, $K^-/K^+$, $\bar{p}/p$, $\bar{\Lambda}/\Lambda$, $\bar{\Sigma}/\Sigma$, $ \bar{\Omega}/\Omega$ 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 $k^+/\pi^+$, $k^-/\pi^-$, $\Omega/\pi^-$, $\bar{p}/\pi^+$, and $\bar{\Omega}/\Omega$, 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 $k^+/\pi^+$, $k^-/\pi^-$, $\Omega/\pi^-$, and $\bar{p}/\pi^+$.

hep-ph↗

arXiv2017

Phenomenology of strangeness production at high energies

The strange-quark occupation factor ($\gamma_s$) is determined from the statistical fit of the multiplicity ratio $\mathrm{K}^+/\pi^+$ in a wide range of nucleon-nucleon center-of-mass energies ($\sqrt{s_{NN}}$). From this single-strange-quark-subsystem, $\gamma_s(\sqrt{s_{NN}})$ was parametrized as a damped trigonometric functionality and successfully implemented to the hadron resonance gas model, at chemical semi-equilibrium. Various particle ratios including $\mathrm{K}^-/\pi^-$, $\mathrm{\Lambda}/\pi^-$, and $\mathrm{\bar{\Lambda}}/\pi^-$ are well reproduced. The phenomenology of $\gamma_s(\sqrt{s_{NN}})$ suggests that, the hadrons ($\gamma_s$ raises) at $\sqrt{s_{NN}} \simeq 7~$GeV seems to undergo a phase transition to a mixed phase ($\gamma_s$ declines), which is then derived into partons ($\gamma_s$ remains unchanged with increasing $\sqrt{s_{NN}}$), at $\sqrt{s_{NN}} \simeq 20~$GeV.

hep-ph↗

arXiv2008

Chaotic quantization and the mass spectrum of fermions

In order to understand the parameters of the standard model of electroweak and strong interactions, one needs to embed the standard model into some larger theory that accounts for the observed values. This means some additional sector is needed that fixes and stabilizes the values of the fundamental constants of nature. We describe how such a sector can be constructed using the so-called chaotic quantization method applied to a system of coupled map lattices. We restrict ourselves in this short note on verifying how our model correctly yields the numerical values of Yukawa and gravitational coupling constants of a collection of heavy and light fermions using a simple principle, the local minimization of vacuum energy.

hep-th↗