-
Regular Friedmann Universes and Matter Transformations Universe (IF 2.9) Pub Date : 2024-03-13 Alexander Kamenshchik, Polina Petriakova
We apply a very simple procedure to construct non-singular cosmological models for flat Friedmann universes filled with minimally coupled scalar fields or by tachyon Born–Infeld-type fields. Remarkably, for the minimally coupled scalar field and the tachyon field, the regularity of the cosmological evolution, or in other words, the existence of bounce, implies the necessity of the transition between
-
Conformally Invariant Gravity and Gravitating Mirages Universe (IF 2.9) Pub Date : 2024-03-17 Victor Berezin, Inna Ivanova
The action of an ideal fluid in Euler variables with a variable number of particles is used for the phenomenological description of the processes of particle creation in strong external fields. It has been demonstrated that the conformal invariance of the creation law imposes quite strict restrictions on the possible types of sources. It is shown that combinations with the particle number density in
-
Multiple SSO Space Debris Flyby Trajectory Design Based on Cislunar Orbit Universe (IF 2.9) Pub Date : 2024-03-16 Siyang Zhang, Shuquan Wang
This paper investigates the trajectory design problem in the scenario of a multiple Sun-synchronous Orbit (SSO) space debris flyby mission from a DRO space station. At first, the characteristics of non-planar transfer from DRO to SSO in the Earth–Moon system are analyzed. The methods of large-scale ergodicity and pruning are utilized to investigate single-impulse and two-impulse DRO–Earth transfers
-
The ASTRI Mini-Array: A New Pathfinder for Imaging Cherenkov Telescope Arrays Universe (IF 2.9) Pub Date : 2024-03-16 Salvatore Scuderi
The ASTRI Mini-Array is an Istituto Nazionale di Astrofisica (INAF) project to build and operate an array of nine Imaging Atmospheric Cherenkov Telescopes (IACTs) at the Teide Astronomical Observatory of the Instituto de Astrofisica de Canarias in Tenerife (Spain) based on a host agreement with INAF and, as such, it will be the largest IACT array until the Cherenkov Telescope Array Observatory starts
-
On the Apparent Discretization of Spacetime and Its Connection with the Cosmological Constant Universe (IF 2.9) Pub Date : 2024-03-14 Jaume Giné, Giuseppe Gaetano Luciano
The emergence of a minimal observable length of order of the Planck scale is a prediction of many quantum theories of gravity. However, the question arises as to whether this is a real fundamental length affecting nature in all of its facets, including spacetime. In this work, we show that the quantum measurement process implies the existence of a minimal measurable length and consequently the apparent
-
Origins and Natures of Inflation, Dark Matter and Dark Energy Universe (IF 2.9) Pub Date : 2024-03-15 Kazuharu Bamba
Various precise cosmological observations, e [...]
-
The Quantum Hall Effect under the Influence of Gravity and Inertia: A Unified Approach Universe (IF 2.9) Pub Date : 2024-03-13 Alexandre Landry, Fayçal Hammad, Reza Saadati
The quantum Hall effect under the influence of gravity and inertia is studied in a unified way. We make use of an algebraic approach, as opposed to an analytic approach. We examine how both the integer and the fractional quantum Hall effects behave under a combined influence of gravity and inertia using a unified Hamiltonian. For that purpose, we first re-derive, using the purely algebraic method,
-
The Relevance of Dynamical Friction for the MW/LMC/SMC Triple System Universe (IF 2.9) Pub Date : 2024-03-14 Wolfgang Oehm, Pavel Kroupa
Simulations of structure formation in the standard cold dark matter cosmological model quantify the dark matter halos of galaxies. Taking into account dynamical friction between dark matter halos, we investigate the past orbital dynamical evolution of the Magellanic Clouds in the presence of the Galaxy. Our calculations are based on a three-body model of rigid Navarro–Frenk–White profiles for dark
-
Classification of Planetary Motion around Super-Jupiters and Brown Dwarfs Universe (IF 2.9) Pub Date : 2024-03-13 Euaggelos E. Zotos, Eman M. Moneer, Tobias C. Hinse
We investigate the orbital dynamics of an exosystem consisting of a solar-mass host star, a transiting body, and an Earth-size exoplanet within the framework of the generalized three-body problem. Depending on its mass, the transiting body can either be a super-Jupiter or a brown dwarf. To determine the final states of the Earth-size exoplanet, we conduct a systematic and detailed classification of
-
Nuclear Modification Factor of Inclusive Charged Particles in Au+Au Collisions at sNN = 27 GeV with the STAR Experiment Universe (IF 2.9) Pub Date : 2024-03-13 Alisher Aitbayev
The Beam Energy Scan (BES) program at RHIC aims to explore the QCD phase diagram, including the search for the evidence of the 1st order phase transition from hadronic matter to Quark-Gluon Plasma (QGP) and the location of the QCD critical point. One of the features previously observed in the study of QGP is the effect of suppression of particle production with high transverse momenta pT (>2 GeV/c)
-
A Critical Discussion on the H0 Tension Universe (IF 2.9) Pub Date : 2024-03-13 Salvatore Capozziello, Giuseppe Sarracino, Giulia De Somma
A critical discussion on the H0 Hubble constant tension is presented by considering both early and late-type observations. From recent precise measurements, discrepancies emerge when comparing results for some cosmological quantities obtained at different redshifts. We highlight the most relevant measurements of H0 and propose potential ideas to solve its tension. These solutions concern the exploration
-
Constraining the Initial Mass Function in the Epoch of Reionization from Astrophysical and Cosmological Data Universe (IF 2.9) Pub Date : 2024-03-13 Andrea Lapi, Giovanni Gandolfi, Lumen Boco, Francesco Gabrielli, Marcella Massardi, Balakrishna S. Haridasu, Carlo Baccigalupi, Alessandro Bressan, Luigi Danese
We aim to constrain the stellar initial mass function (IMF) during the epoch of reionization. To this purpose, we build up a semi-empirical model for the reionization history of the Universe based on various ingredients: the latest determination of the UV galaxy luminosity function from JWST out to redshift z≲12; data-inferred and simulation-driven assumptions on the redshift-dependent escape fraction
-
Isovector Axial Charge and Form Factors of Nucleons from Lattice QCD Universe (IF 2.9) Pub Date : 2024-03-12 Rajan Gupta
A survey of the calculations of the isovector axial vector form factor of the nucleon using lattice QCD is presented. Attention is paid to statistical and systematic uncertainties, in particular those due to excited state contributions. Based on a comparison of results from various collaborations, a case is made that lattice results are consistent within 10%. A similar level of uncertainty is in the
-
Weak Coupling Regime in Dilatonic f(R,T) Cosmology Universe (IF 2.9) Pub Date : 2024-03-11 Francisco A. Brito, Carlos H. A. B. Borges, José A. V. Campos, Francisco G. Costa
We consider f(R,T) modified theories of gravity in the context of string-theory-inspired dilaton gravity. We deal with a specific model that under certain conditions describes the late time Universe in accord with observational data in modern cosmology and addresses the H0 tension. This is done by exploring the space of parameters made out of those coming from the modified gravity and dilatonic charge
-
Analysis of the Geodesic Motions of Massive Particles in Kerr–Sen–AdS4 Spacetime Universe (IF 2.9) Pub Date : 2024-03-08 Ziqiang Cai, Ming Liu, Wen-Qian Wang, Tong-Yu He, Zhan-Wen Han, Rong-Jia Yang
We consider geodesic motions in Kerr–Sen–AdS4 spacetime. We obtain equations of motion for light rays and test particles. Using parametric diagrams, we show some regions where radial and latitudinal geodesic motions are allowed. We analyze the impact of parameters related to the dilatonic scalar on the orbit and find that it will result in more rich and complex orbital types.
-
A Simple Direct Empirical Observation of Systematic Bias of the Redshift as a Distance Indicator Universe (IF 2.9) Pub Date : 2024-03-06 Lior Shamir
Recent puzzling observations, such as the H0 tension, large-scale anisotropies, and massive disk galaxies at high redshifts, have been challenging the standard cosmological model. While one possible explanation is that the standard model is incomplete, other theories are based on the contention that the redshift model as a distance indicator might be biased. These theories can explain the recent observations
-
The Modeling of Pulsar Magnetosphere and Radiation Universe (IF 2.9) Pub Date : 2024-03-07 Gang Cao, Xiongbang Yang, Li Zhang
We review the recent advances in the pulsar high-energy γ-ray observation and the electrodynamics of the pulsar magnetospheres from the early vacuum model to the recent plasma-filled models by numerical simulations. The numerical simulations have made significant progress toward the self-consistent modeling of the plasma-filled magnetosphere by including the particle acceleration and radiation. The
-
Transport Coefficients of Relativistic Matter: A Detailed Formalism with a Gross Knowledge of Their Magnitude Universe (IF 2.9) Pub Date : 2024-03-07 Ashutosh Dwibedi, Nandita Padhan, Arghya Chatterjee, Sabyasachi Ghosh
The present review article has attempted a compact formalism description of transport coefficient calculations for relativistic fluid, which is expected in heavy ion collision experiments. Here, we first address the macroscopic description of relativistic fluid dynamics and then its microscopic description based on the kinetic theory framework. We also address different relaxation time approximation-based
-
Correction: Cuello, N.; Sucerquia, M. Alpha Centauri: Disc Dynamics, Planet Stability, Detectability. Universe 2024, 10, 64 Universe (IF 2.9) Pub Date : 2024-03-04 Nicolás Cuello, Mario Sucerquia
In the original publication [...]
-
Assessing the Similarity of Continuous Gravitational-Wave Signals to Narrow Instrumental Artifacts Universe (IF 2.9) Pub Date : 2024-03-04 Rafel Jaume, Rodrigo Tenorio, Alicia M. Sintes
Continuous gravitational-wave (CW) signals are long-lasting quasi-monochromatic gravitational-wave signals expected to be emitted by rapidly rotating non-axisymmetric neutron stars. Depending on the rotational frequency and sky location of the source, certain CW signals may behave in a similar manner to narrow-band artifacts present in ground-based interferometric detectors. Part of the detector characterization
-
Theoretically Motivated Dark Electromagnetism as the Origin of Relativistic Modified Newtonian Dynamics Universe (IF 2.9) Pub Date : 2024-03-04 Felix Finster, José M. Isidro, Claudio F. Paganini, Tejinder P. Singh
The present paper is a modest attempt to initiate the research program outlined in this abstract. We propose that general relativity and relativistic MOND (RelMOND) are analogues of broken electroweak symmetry. That is, SU(2)R×U(1)YDEM→U(1)DEM (DEM stands for dark electromagnetism), and GR is assumed to arise from the broken SU(2)R symmetry and is analogous to the weak force. RelMOND is identified
-
Simple Lévy α-Stable Model Analysis of Elastic pp and pp¯ Low-|t| Data from SPS to LHC Energies Universe (IF 2.9) Pub Date : 2024-03-06 Tamás Csörgő, Sándor Hegyi, István Szanyi
A simple Lévy α-stable (SL) model is used to describe the data on elastic pp and pp¯ scattering at low-|t| from SPS energies up to LHC energies. The SL model is demonstrated to describe the data with a strong non-exponential feature in a statistically acceptable manner. The energy dependence of the parameters of the model is determined and analyzed. The Lévy α parameter of the model has an energy-independent
-
On Phase Transitions during Collisions near the Horizon of Black Holes Universe (IF 2.9) Pub Date : 2024-03-07 Andrey A. Grib, Yuri V. Pavlov
During particle collisions in the vicinity of the horizon of black holes, it is possible to achieve energies and temperatures corresponding to phase transitions in particle physics. It is shown that the sizes of the regions of the new phase are of the order of the Compton length for the corresponding mass scale. The lifetime is also on the order of the Compton time. It is shown that the inverse influence
-
Heavy Flavor Physics at the sPHENIX Experiment Universe (IF 2.9) Pub Date : 2024-03-06 Zhaozhong Shi
The sPHENIX experiment is a state-of-the-art jet and heavy flavor physics detector, which successfully recorded its first Au + Au collision data at 200 GeV at the Relativistic Heavy Ion Collider (RHIC). sPHENIX will provide heavy flavor physics measurements at RHIC, covering an unexplored kinematic region and unprecedented precision, to probe the parton energy loss mechanism, parton transport coefficients
-
Re-Examination of the Effect of Pairing Gaps on Gamow–Teller Strength Distributions and β-Decay Rates Universe (IF 2.9) Pub Date : 2024-03-06 Jameel-Un Nabi, Muhammad Riaz, Arslan Mehmood
β-decay is one of the key factors for understanding the r-process and evolution of massive stars. The Gamow–Teller (GT) transitions drive the β-decay process. We employ the proton–neutron quasiparticle random phase approximation (pn-QRPA) model to calculate terrestrial and stellar β-decay rates for 50 top-ranked nuclei possessing astrophysical significance according to a recent survey. The model parameters
-
The Nature of Dark Energy and Constraints on Its Hypothetical Constituents from Force Measurements Universe (IF 2.9) Pub Date : 2024-03-04 Galina L. Klimchitskaya, Vladimir M. Mostepanenko
This review considers the theoretical approaches to the understanding of dark energy, which comprises approximately 68% of the energy of our Universe and explains the acceleration in its expansion. Following a discussion of the main approach based on Einstein’s equations with the cosmological term, the explanations of dark energy using the concept of some kind of scalar field are elucidated. These
-
Observational Constraints on Dynamical Dark Energy Models Universe (IF 2.9) Pub Date : 2024-03-04 Olga Avsajanishvili, Gennady Y. Chitov, Tina Kahniashvili, Sayan Mandal, Lado Samushia
Scalar field ϕCDM models provide an alternative to the standard ΛCDM paradigm, while being physically better motivated. Dynamical scalar field ϕCDM models are divided into two classes: the quintessence (minimally and non-minimally interacting with gravity) and phantom models. These models explain the phenomenology of late-time dark energy. In these models, energy density and pressure are time-dependent
-
Top Quark at the New Physics Frontier Universe (IF 2.9) Pub Date : 2024-03-05 Efe Yazgan, Pedro Silva
This Special Issue of Universe is devoted to the most massive fundamental elementary particle known, the top quark [...]
-
On Minimal Entanglement Wedge Cross Section for Holographic Entanglement Negativity Universe (IF 2.9) Pub Date : 2024-03-05 Jaydeep Kumar Basak, Vinay Malvimat, Himanshu Parihar, Boudhayan Paul, Gautam Sengupta
We demonstrate the equivalence of two different conjectures in the literature for the holographic entanglement negativity in AdS3/CFT2, modulo certain constants. These proposals involve certain algebraic sums of bulk geodesics homologous to specific combinations of subsystems, and the entanglement wedge cross section (EWCS) backreacted by a cosmic brane for the conical defect geometry in the bulk gravitational
-
The “Drake Equation” of Exomoons—A Cascade of Formation, Stability and Detection Universe (IF 2.9) Pub Date : 2024-02-28 Gyula M. Szabó, Jean Schneider, Zoltán Dencs, Szilárd Kálmán
After 25 years of the prediction of the possibility of observations, and despite the many hundreds of well-studied transiting exoplanet systems, we are still waiting for the announcement of the first confirmed exomoon. We follow the “cascade” structure of the Drake equation but apply it to the chain of events leading to a successful detection of an exomoon. The scope of this paper is to reveal the
-
Understanding the Effect of Conserved Charges on the Coalescence Sum Rule of Directed Flow Universe (IF 2.9) Pub Date : 2024-03-01 Kishora Nayak, Shu-Su Shi, Zi-Wei Lin
Recently, the rapidity-odd directed flow (v1) of produced hadrons (K−, ϕ, p¯, Λ¯, Ξ¯+, Ω−, and Ω¯+) has been studied. Several combinations of these produced hadrons, with very small mass differences but differences in the net electric charge (Δq) and net strangeness (ΔS) on the two sides, have been considered. A difference in v1 between the two sides of these combinations (Δv1) has been proposed as
-
On the Copenhagen Interpretation of Quantum Measurement Universe (IF 2.9) Pub Date : 2024-03-01 Michael L. Walker
We claim that quantum collapse, as per the Copenhagen interpretation of quantum mechanics, follows naturally from the energetics of measurement. We argue that a realistic device generates an interaction energy that drives a random walk in Hilbert space and generates the probabilistic interpretation of Born.
-
Unveiling the Emission and Variation Mechanism of Mrk 501: Using the Multi-Wavelength Data at Different Time Scale Universe (IF 2.9) Pub Date : 2024-03-01 Lizhi Liu, Yunguo Jiang, Junhao Deng, Zhaohao Chen, Chenli Ma
Variability study at multi-frequency provides us with rich information of the emission and variation mechanism for blazars. In this work, we present a comprehensive multi-frequency analysis of the high-synchrotron-peaked (HSP) blazar Mrk 501, using γ-ray, X-ray, optical, optical polarization, and radio data. The multiple-wavelength light curves are analyzed by using the localized cross-correlation
-
Quark Clusters, QCD Vacuum and the Cosmological 7Li, Dark Matter and Dark Energy Problems Universe (IF 2.9) Pub Date : 2024-03-01 Rachid Ouyed, Denis Leahy, Nico Koning, Prashanth Jaikumar
We propose a non-exotic electromagnetic solution (within the standard model of particle physics) to the cosmological 7Li problem based upon a narrow 2 MeV photo-emission line from the decay of light glueballs (LGBs). These LGBs form within color superconducting quark clusters (SQCs), which are tens of Fermi in size, in the radiation-dominated post-BBN epoch. The mono-chromatic line from the LGB→γ+γ
-
Quantum Clock in the Projection Evolution Formalism Universe (IF 2.9) Pub Date : 2024-03-01 Andrzej Góźdź, Marek Góźdź
Using the projection evolution (PEv) approach, time can be included in quantum mechanics as an observable. Having the time operator, it is possible to explore the temporal structure of various quantum events. In the present paper, we discuss the possibility of constructing a quantum clock which advances in time during its quantum evolution, in each step having some probability to localize itself on
-
The Language of Spheres in Physics Universe (IF 2.9) Pub Date : 2024-03-01 Jean-Pierre Gazeau
Physical laws manifest themselves through the amalgamation of mathematical symbols, numbers, functions, geometries, and relationships. These intricate combinations unfold within a mathematical model devised to capture and represent the “objective reality” of the system under examination. In this symbiotic relationship between physics and mathematics, the language of mathematics becomes a powerful tool
-
First-Order Event Plane Correlated Directed and Triangular Flow from Fixed-Target Energies at RHIC-STAR Universe (IF 2.9) Pub Date : 2024-03-01 Sharang Rav Sharma
We report the measurement of first-order event plane-correlated directed flow (v1) and triangular flow (v3) for identified hadrons (π±, K±, and p), net particle (net-K, net-p), and light nuclei (d and t) in Au + Au collisions at sNN = 3.2, 3.5, and 3.9 GeV in the fixed-target mode from the second phase of the beam energy scan (BES-II) program at RHIC-STAR. The v1 slopes at mid-rapidity for identified
-
The QCD Vacuum as a Disordered Chromomagnetic Condensate Universe (IF 2.9) Pub Date : 2024-02-29 Paolo Cea
An attempt is made to describe from first principles the large-scale structure of the confining vacuum in quantum chromodynamics. Starting from our previous variational studies of the SU(2) pure gauge theory in an external Abelian chromomagnetic field and extending Feynman’s qualitative analysis in (2+1)-dimensional SU(2) gauge theory, we show that the SU(3) vacuum in three-space and one-time dimensions
-
Characterizing Timing Noise in Normal Pulsars with the Nanshan Radio Telescope Universe (IF 2.9) Pub Date : 2024-02-26 Jianping Yuan, Na Wang, Shijun Dang, Lin Li, Feifei Kou, Wenming Yan, Zhigang Wen, Zhiyong Liu, Rai Yuen, Jingbo Wang, Zurong Zhou, Peng Liu, Dalin He
We present a decade of observations of pulse arrival times for 85 pulsars using the Nanshan radio telescope from July 2002 to March 2014. The Cholesky method can accurately estimate the covariance function of the timing residuals, significantly improving the parameter’s estimation accuracy when red noise is prominent. We utilize the Cholesky method to determine positions and basic timing parameters
-
Periodic Behavior of Selected Solar, Geomagnetic and Cosmic Activity Indices during Solar Cycle 24 Universe (IF 2.9) Pub Date : 2024-02-27 Ali Kilcik, Jean-Pierre Rozelot, Atila Ozguc
In this study, we performed periodicity analyses of selected daily solar (flare index, coronal index, number of coronal mass ejections), geomagnetic (planetary equivalent range index, disturbance storm time index, interplanetary magnetic field) and cosmic ray indices for the last Solar Cycle 24 (from December 2008 to December 2019). To study the periodic variation of the above-listed datasets, the
-
Search for Wormhole Candidates: Accreting Wormholes with Monopole Magnetic Fields Universe (IF 2.9) Pub Date : 2024-02-27 Mikhail Piotrovich, Serguei Krasnikov, Stanislava Buliga, Tinatin Natsvlishvili
The existence of even the simplest magnetized wormholes may lead to observable consequences. In the case where both the wormhole and the magnetic field around its mouths are static and spherically symmetric, and gas in the region near the wormhole falls radially into it, the former’s spectrum contains bright cyclotron or synchrotron lines due to the interaction of charged plasma particles with the
-
Recent Findings from Heavy-Flavor Angular Correlation Measurements in Hadronic Collisions Universe (IF 2.9) Pub Date : 2024-02-27 Deepa Thomas, Fabio Colamaria
The study of angular correlations of heavy-flavor particles in hadronic collisions can provide crucial insight into the heavy quark production, showering, and hadronization processes. The comparison with model predictions allows us to discriminate among different approaches for heavy quark production and hadronization, as well as different treatments of the underlying event employed by the models to
-
Properties of the Top Quark Universe (IF 2.9) Pub Date : 2024-02-26 Andreas Jung
Recent measurements of the properties of the top quark at the CERN Large Hadron Collider are discussed. The results were measured for single and top quark pair production in their final states, including jets with either one or two leptons or only in hadronic final states. Top quark properties include angular correlations, top quark spin correlations, mass, and width. When looking towards the future
-
Pion Interferometry with Lévy-Stable Sources in sNN = 200 GeV Au + Au Collisions at STAR Universe (IF 2.9) Pub Date : 2024-02-20 Dániel Kincses
Measurements of femtoscopic correlations in high-energy heavy-ion collisions are used to unravel the space–time structure of the particle-emitting source (the quark–gluon plasma). Recent results indicate that the pion pair source exhibits a power law behavior and can be described well by a Lévy distribution. In this study, Lévy fits were applied to the measured one-dimensional two-pion correlation
-
Two-Pomeron Interaction Universe (IF 2.9) Pub Date : 2024-02-20 Luis Cancino Arancibia, Carlos Contreras
We study the interaction of two discrete pomeron fields while considering mass mixing and the general structure of the interaction potential for pomerons within the framework for a functional renormalization group analysis of Reggeon field theory. We find fixed points from the zeros of the beta function establishing the existence of three groups of solutions: the first corresponds to two uncoupled
-
No-Boundary Wave Functional and Own Mass of the Universe Universe (IF 2.9) Pub Date : 2024-02-19 Natalia Gorobey, Alexander Lukyanenko, Alexander V. Goltsev
An alternative formulation of the no-boundary initial state of the universe in the Euclidean quantum theory of gravity is proposed. Unlike the no-boundary Hartle–Hawking wave function, in which time appears together with macroscopic space–time in the semiclassical approximation, in the proposed formalism, time is present from the very beginning on an equal footing with spatial coordinates. The main
-
Falling into the Past: Geodesics in a Time Travel Metric Universe (IF 2.9) Pub Date : 2024-02-16 Colin MacLaurin, Fabio Costa, Timothy C. Ralph
We investigate timelike and null geodesics within the rotating “time machine” spacetime proposed by Ralph, T.C.; et al. Phys. Rev. D 2020, 102, 124013. This is a rotating analogue of Alcubierre’s warp drive spacetime. We obtain geodesics that begin and end in the surrounding flat space region, yet achieve time travel relative to static observers there. This is a global property, as the geodesics remain
-
Swarm Intelligence Methods for Extreme Mass Ratio Inspiral Search: First Application of Particle Swarm Optimization Universe (IF 2.9) Pub Date : 2024-02-17 Xiao-Bo Zou, Soumya D. Mohanty, Hong-Gang Luo, Yu-Xiao Liu
Swarm intelligence (SI) methods are nature-inspired metaheuristics for global optimization that exploit a coordinated stochastic search strategy by a group of agents. Particle swarm optimization (PSO) is an established SI method that has been applied successfully to the optimization of rugged high-dimensional likelihood functions, a problem that represents the main bottleneck across a variety of gravitational
-
A Systematic Study of Two-Neutrino Double Electron Capture Universe (IF 2.9) Pub Date : 2024-02-17 Ovidiu Niţescu, Stefan Ghinescu, Sabin Stoica, Fedor Šimkovic
In this paper, we update the phase-space factors for all two-neutrino double electron capture processes. The Dirac–Hartree–Fock–Slater self-consistent method is employed to describe the bound states of captured electrons, enabling a more realistic treatment of atomic screening and more precise binding energies of the captured electrons compared to previous investigations. Additionally, we consider
-
Study of Angular Resolution Using Imaging Atmospheric Cherenkov Technique Universe (IF 2.9) Pub Date : 2024-02-18 Jinrui Liu, Hanxun Wu, Qi Liu, Yujie Ji, Rui Xu, Feng Zhang, Hu Liu
Angular resolution is crucial for the detailed study of gamma-ray sources and current Cherenkov telescopes (e.g., HESS, MAGIC, and VERITAS) that operate below tens of TeV. Several gamma-ray sources with a photon energy larger than 100 TeV have been revealed by the LHAASO in recent years; the angular resolution of the LHAASO is around 0.3∘. A gamma-ray detector with an angular resolution of less than
-
On the Possibility of a Static Universe Universe (IF 2.9) Pub Date : 2024-02-16 Júlio C. Fabris, Felipe T. Falciano, Luiz F. Guimarães, Nelson Pinto-Neto
After a century of cosmological observations, we have a solid standard model of cosmology. However, from a theoretical viewpoint, it is a compelling question if the cosmological data inevitably require an expanding universe independently of the theoretical framework. The possibility of obtaining a viable cosmological model with a constant scale-factor is discussed in the context of the Brans–Dicke
-
Revisiting a Core–Jet Laboratory at High Redshift: Analysis of the Radio Jet in the Quasar PKS 2215+020 at z = 3.572 Universe (IF 2.9) Pub Date : 2024-02-17 Sándor Frey, Judit Fogasy, Krisztina Perger, Kateryna Kulish, Petra Benke, Dávid Koller, Krisztina Éva Gabányi
The prominent radio quasar PKS 2215+020 (J2217+0220) was once labelled as a new laboratory for core–jet physics at redshift z=3.572 because of its exceptionally extended jet structure traceable with very long baseline interferometric (VLBI) observations up to a ∼600 pc projected distance from the compact core and a hint of an arcsec-scale radio and an X-ray jet. While the presence of an X-ray jet could
-
Symmetries and the Hilbert Space of Large N Extended States Universe (IF 2.9) Pub Date : 2024-02-17 Antal Jevicki, Xianlong Liu, Junjie Zheng
We discuss the large N expansion in backgrounds of extended states with a focus on the implementation of Goldstone symmetries and the construction of the associated Hilbert space. The formulation is given in the general framework of collective field theory. The case of translational symmetry is described first as a basic example. The large N thermofield represents the main topics, with the emergent
-
Science with the ASTRI Mini-Array: From Experiment to Open Observatory Universe (IF 2.9) Pub Date : 2024-02-16 Stefano Vercellone
Although celestial sources emitting in the few tens of GeV up to a few TeV are being investigated by imaging atmospheric Čerenkov telescope arrays such as H.E.S.S., MAGIC, and VERITAS, at higher energies, up to PeV, more suitable instrumentation is required to detect ultra-high-energy photons, such as extensive air shower arrays, as HAWC, LHAASO, Tibet AS-γ. The Italian National Institute for Astrophysics
-
Induced Isotensor Interactions in Heavy-Ion Double-Charge-Exchange Reactions and the Role of Initial and Final State Interactions Universe (IF 2.9) Pub Date : 2024-02-16 Horst Lenske, Jessica Bellone, Maria Colonna, Danilo Gambacurta, José-Antonio Lay
The role of initial state (ISI) and final state (FSI) ion–ion interactions in heavy-ion double-charge-exchange (DCE) reactions A(Z,N)→A(Z±2,N∓2) are studied for double single-charge-exchange (DSCE) reactions given by sequential actions of the isovector nucleon–nucleon (NN) T-matrix. In momentum representation, the second-order DSCE reaction amplitude is shown to be given in factorized form by projectile
-
A Loop Quantum-Corrected Family of Chiral Cosmology Models Universe (IF 2.9) Pub Date : 2024-02-12 Luis Rey Díaz-Barrón, Abraham Espinoza-García, Sinuhé Alejandro Pérez-Payán, J. Socorro
We construct and examine a holonomy-corrected chiral fields model of cosmological relevance. Specifically, we holonomize the Hamiltonian corresponding to a quintom field scenario with additional kinetic interaction (governed by the constant chiral metric, mab) on a flat FLRW background and contrast the resulting model with the corresponding purely classical system. In particular, it is shown that the
-
On the Hole Argument and the Physical Interpretation of General Relativity Universe (IF 2.9) Pub Date : 2024-02-14 Jaume de Haro
Einstein presented the Hole Argument against General Covariance, understood as invariance with respect to a change in coordinates, as a consequence of his initial failure to obtain covariant equations that, in the weak static limit, contain Newton’s law. Fortunately, about two years later, Einstein returned to General Covariance, and found these famous equations of gravity. However, the rejection of
-
Proposal for an Electromagnetic Mass Formula for the X17 Particle Universe (IF 2.9) Pub Date : 2024-02-12 Sándor Varró
Recent observations of anomalous angular correlations of electron–positron pairs in several nuclear reactions have indicated the existence of a hypothetical neutral boson of rest mass ~17 MeV/c2, called the X17 particle. Similarly, one has interpreted an independent set of experiments on photon pair spectra around the invariant mass ~38 MeV/c2, by assuming the existence of the so-called E38 particle
-
Thermodynamics and Phase Transitions of Dyonic AdS Black Holes in Gauss-Bonnet-Scalar Gravity Universe (IF 2.9) Pub Date : 2024-02-12 Pinghui Mou, Zhengzhou Yan, Guoping Li
In this paper, by treating the cosmological constant as a thermodynamic pressure, we study the thermodynamics and phase transitions of the dyonic AdS black holes in Gauss-Bonnet-Scalar gravity, where the conformal scalar field is considered. In a more general extended phase space, we first verified the first law of black hole thermodynamics, and find that it is always true. Meanwhile, the corresponding
-
Diffeomorphism Covariance and the Quantum Schwarzschild Interior Universe (IF 2.9) Pub Date : 2024-02-13 I. W. Bornhoeft, R. G. Dias, J. S. Engle
We introduce a notion of residual diffeomorphism covariance in quantum Kantowski–Sachs (KS) describing the interior of a Schwarzschild black hole. We solve for the family of Hamiltonian constraint operators satisfying the associated covariance condition, as well as parity invariance, preservation of the Bohr Hilbert space of the Loop Quantum KS and a correct (naïve) classical limit. We further explore