International Journal of Modern Physics A

Electron densities in different locations of our galaxy are obtained in pulsar astronomy by dividing the dispersion measure (DM) by the distance of the pulsar to Earth. The properties of the interstellar plasma are related to its heating by cosmic rays. Following the present analysis, DM’s measurements are obtained with different properties of the corresponding plasmas at different temperatures. (1) For relatively low temperatures (around and below 10,000 (K)), the state of molecular, atomic and ionized hydrogen is analyzed by the interstellar medium model with partially ionized plasma. In this region, various spectroscopic effects are obtained. (2) For temperatures above this limit, the interstellar gas is found to be a completely ionized medium, and this plasma is defined as warm ionized medium (WIM) plasma. We show in the first part of the paper that this plasma is transparent, as obtained from the solution of Saha’s equation. The index of refraction of the WIM plasma is real, but the plasma can be observed by dispersion measurements. (3) For very high temperatures (around 1 million (K)), the plasma is defined as hot ionized medium, where X-rays are obtained. We concentrate in the present work on the analysis of WIM plasma. We calculate the mass densities of this plasma and compare it with dark matter mass densities, which are found to be larger. But some factors which may reduce this difference are discussed.

Texture matrices are used to mitigate the redundancy inherent in the description of flavor physics via Yukawa couplings by eliminating some entries in order to identify relevant parameters. In this paper, the implications of a 2-zero texture mixing matrix in the parallel case are studied for leptons. Eight possible parametrizations were found and the parameter space was studied for all the scenarios using a chi-squared analysis. Using a model of GUT with $SO(10)$ symmetry, the mass matrices were restricted and a reduction of parameters was possible by adding the previously proposed Universal Texture Constraint for two scenarios. Constrains on the mass of the heaviest neutrino were found and the interval favored by UTC is $m_{{\nu }_3}\le 0.3$eV as well as general properties of the free parameters of the model.

The ATLAS experiment at CERN relies on a Worldwide Distributed Computing Grid infrastructure to support its physics program at the Large Hadron Collider. ATLAS has integrated cloud computing resources to complement its Grid infrastructure and conducted an R&D program on Google Cloud Platform. These initiatives leverage key features of commercial cloud providers: lightweight configuration and operation, elasticity and availability of diverse infrastructures. This paper examines the seamless integration of cloud computing services as a conventional Grid site within the ATLAS workflow management and data management systems, while also offering new setups for interactive, parallel analysis. It underscores pivotal results that enhance the on-site computing model and outlines several R&D projects that have benefited from large-scale, elastic resource provisioning models. Furthermore, this study discusses the impact of cloud-enabled R&D projects in three domains: accelerators and AI/ML, ARM CPUs and columnar data analysis techniques.

I propose a unified model of particle physic and cosmology based on both a new extension of the standard particle model and the fundamental principle of the standard cosmology. Beyond the standard model, I introduce several species of dark fields with the dark symmetry of $Z_2\otimes Z_2^{\prime }$, the inflation field, cold dark matter (CDM) and dark energy (DE) are of course included among them. The model can coherently and completely describe the origin and evolution of the universe from the primordial inflation to the reheating, to the baryogenesis, to the current CDM and DE, and also the neutrino mass generation mechanism. For the energy evolution of each phase, I give its dynamical system of equations, and solve them by some special techniques. The numerical results can clearly show how each evolution is successfully implemented, furthermore, the model demonstrates that the DE genesis is purely from the CDM condensation, which is essentially a reverse process of the primordial slow-roll inflation, there is not the so-called “cosmological constant energy”. By use of fewer input parameters, the model not only exactly reproduces the measured inflationary data and the current energy density budget, but also finely predicts such important values as the tensor-to-scalar ratio $r_{0.05}\approx 1.68\times 10^{-6}$, the inflaton mass $M_{\mathrm{\Phi }}\approx 5.05\times 10^{10}$GeV, the reheating temperature $T_{re}\approx 8.29\times 10^{10}$GeV, the CDM mass $M_S\approx 256$GeV, ${\eta }_B\approx 6.14\times 10^{-10}$ and $h\approx 0.73$, in particular, the model smoothly clarifies and eliminates the “Hubble tension”. In short, the unified model newly establishes the deeper and closer relations between particle physics and cosmology, therefore we expect the ongoing and future experiments to test the model.

The nonrelativistic Pauli equation is used to study the interaction of slow neutrons with an ultrashort laser pulse. In the extreme limit, the pulse is acting on the magnetic moment of the neutron only at one instant of time. We obtain the scattering amplitude by deriving the junction conditions for the Pauli wave function across the pulse. Explicit expressions are given for a beam of polarized plane wave neutrons subjected to a pulse of spatially constant magnetic field strength. Finally we provide crude numerical estimates for pulses with the highest intensity available today.

A modified fourth-order gravity theory namely the $f(T,B)$ theory is considered in flat FLRW model to investigate both classical and quantum cosmology. The field equations are reduced to second-order differential equations by considering the technique of Lagrange multiplier. Noether symmetry analysis has been used both for obtaining classical solution and the wave function of the Universe in quantum cosmology. Finally the cosmological solutions are examined from observational view point.

In this paper, fractal space–time, the Hubble horizon and the energy–momentum tensor are examined in relation to the FLRW metric. It offers a Fractal Friedman equation along with its answer. Also included is the scale factor, which includes fractal structures for closed, flat and open universes. They offer fresh insights into the behavior and evolution of the universe through detailed plots that vividly illustrate their potential cosmological implications.