Article
Physics, Multidisciplinary
Salah Haggag
Summary: A new approach to construct relativistic stellar models is presented, which formulates the problem as an optimal control problem with an objective function to be optimized. The results show that using this approach, the equation of state for a relativistic incompressible fluid can be determined. The article also explores extensions to other configurations.
Article
Physics, Nuclear
Fu Ma, Chen Wu, Wenjun Guo
Summary: In this study, we investigate the equation of state of dense baryon matter using the relativistic mean-field model. We incorporate the Delta(1232) isobars in the IUFSU model with hyperons and consider the potential condensation of kaon mesons. It is found that the presence of Delta resonances is necessary for the stability of a massive neutron star, and the addition of Delta resonance leads to a softer equation of state in the low density region, consistent with observational data.
Article
Physics, Nuclear
Giuliano Giacalone, Chun Shen
Summary: The study shows that event-shape engineering based on the mean transverse momentum of charged hadrons provides an optimal handle on the strength of the magnetic field in central heavy-ion collisions. Quantitative evaluations reveal a correlation between the event-by-event magnetic field and [p(t)]. The new method offers advantages for the experimental search of the chiral magnetic effect.
EUROPEAN PHYSICAL JOURNAL A
(2021)
Article
Astronomy & Astrophysics
Helena Pais, Oleksii Ivanytskyi, Constanca Providencia
Summary: This study calculates the nuclear matter properties using a relativistic approach suitable for multi-component systems. The effects of density dependence of symmetry energy and Landau quantization in the presence of a strong external magnetic field are discussed. The results show a large dispersion in the calculated properties at high densities, as well as sensitivity of proton Landau mass and parameters to symmetry energy. The impact of magnetic field on nuclear properties is minimal except in a narrow range of densities near the crust-core transition.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Tsuyoshi Miyatsu, Myung-Ki Cheoun, Koichi Saito
Summary: Using the relativistic mean-field model, this study investigates the properties of isospin-asymmetric nuclear matter, considering the couplings between isoscalar and isovector mesons. The effects of vector mixing and quartic interactions on nuclear symmetry energy and neutron star properties are examined. The findings reveal that the delta meson increases nuclear symmetry energy at high densities, while the mixing of sigma and delta mesons softens the symmetry energy above the saturation density. The delta meson and its mixing also have a significant influence on the radius and tidal deformability of a neutron star. In particular, the mixing reduces the neutron star radius, allowing for a simultaneous reproduction of the observed tidal deformabilities of neutron stars.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Digvijay Wadekar, Zihui Wang
Summary: Gas-rich dwarf galaxies provide sensitive probes for the properties and decay processes of dark matter. Observations of these galaxies can provide important constraints on the decay lifetime and annihilation of dark matter, contributing to our understanding of dark matter models.
Article
Physics, Nuclear
Rahul Somasundaram, Jerome Margueron, Guy Chanfray, Hubert Hansen
Summary: This article explores three different classes of relativistic approaches for dense nuclear matter and addresses parameter uncertainties. The results show that the predictions of these models differ as density increases, and that only half of the empirical symmetry energy can be reproduced by these three models.
EUROPEAN PHYSICAL JOURNAL A
(2022)
Article
Astronomy & Astrophysics
Shen Yang, Dehua Wen
Summary: Motivated by terrestrial experiments, the correlations between nuclear matter parameters and neutron star properties have been analyzed and used to constrain their uncertainties. It is observed that the neutron star properties, such as radius R and tidal deformability A, are notably correlated with the slope of symmetry energy L. The constraints on L = 54 +/- 8 MeV lead to consistent neutron star properties with GW170817 and NICER observation constraints, and also provide constraints on low-mass neutron star properties.
Article
Astronomy & Astrophysics
Xiao-Liang Xia, Hui Li, Xu-Guang Huang, Huan Zhong Huang
Summary: This study investigates the spin alignment of vector mesons from locally polarized quarks and anti-quarks in heavy-ion collisions, finding that the observed deviations do not necessarily indicate global polarization but could also stem from local spin alignment induced by local vorticity. Proposed experimental observables can distinguish between local and global spin alignments, offering insights into the patterns of vorticity and the puzzles of phi and K-*0 spin alignments in heavy-ion collisions.
Article
Environmental Sciences
Xuemin Zhang, Lei Dong, Lei Nie
Summary: The observations from the China Seismo-Electromagnetic Satellite (CSES) were analyzed during the largest magnetic storm in 2018. The study revealed the temporal and spatial evolution of electromagnetic fields and plasma parameters during different phases of the storm. Strong correlations were observed between electric fields and electron density.
Article
Physics, Nuclear
Ankit Kumar, H. C. Das, Manpreet Kaur, M. Bhuyan, S. K. Patra
Summary: In this study, a density-dependent analytical expression of binding energy per nucleon for nuclear matter with different neutron-proton asymmetry was obtained through polynomial fitting. Various nuclear matter parameters were calculated using this expression, and the properties of light and heavy nuclei showed significant differences, indicating a structural dependence on the density distribution of each nucleus. Comparisons were also made with results obtained through Bruckner energy density functional.
Article
Physics, Multidisciplinary
Xing-Long Zhu, Wei-Yuan Liu, Min Chen, Su-Ming Weng, Dong Wu, Tong-Pu Yu, Wei-Min Wang, Zheng-Ming Sheng, Jie Zhang
Summary: In this study, a new approach to access the strong-field QED regime in the laboratory is presented, which involves self-pinching an electron beam to near-solid-density by passing it through a properly designed hollow cone target. This beam-focusing scheme can significantly reduce the beam diameter and increase its density, leading to the production of ultradense electron beams. These ultradense electron beams can unlock a new regime of QED-dominated beam-plasma interactions.
NEW JOURNAL OF PHYSICS
(2023)
Article
Physics, Nuclear
Olfa Boukari, Helena Pais, Sofija Antic, Constanca Providencia
Summary: The study shows that although different equations of state are constrained by the same data, the properties of very asymmetric nuclear matter differ significantly among models. Some models predict larger transition densities to homogeneous matter for beta-equilibrated matter than for symmetric nuclear matter.
Article
Physics, Multidisciplinary
Jeet Amrit Pattnaik, M. Bhuyan, R. N. Panda, S. K. Patra
Summary: Ground-state properties for isotopic chain of Ca, Sn, Pb, and Z = 120 nuclei are calculated using various forces and sets in the relativistic mean-field approximation. A three-point formula is used to locate magic numbers in the superheavy region and explain observed kinks. Peeks are found at known neutron magic numbers with confirmation of sub-shell and shell closure at specific neutron numbers.
Article
Astronomy & Astrophysics
Daneng Yang, Ethan O. Nadler, Hai-Bo Yu
Summary: We conducted a high-resolution cosmological zoom-in simulation of a Milky Way-like system and investigated the effects of dark matter self-interactions on satellite, splashback, and isolated halos. Our study demonstrates how self-interactions diversify halo populations in an environmentally dependent fashion within and surrounding MW-mass hosts, providing a compelling avenue to address the diverse dark matter distributions of observed dwarf galaxies.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Utsav Murarka, Kinjal Banerjee, Tuhin Malik, Constanca Providencia
Summary: This paper applies machine learning algorithms to predict the binding energy of atomic nuclei and constructs the outer crust equation of state of a neutron star. The study demonstrates that the model is comparable to existing models in terms of accuracy and provides guidance for the physics community in choosing suitable machine learning algorithms for their datasets.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Tuhin Malik, Marcio Ferreira, B. K. Agrawal, Constanca Providencia
Summary: The general behavior of the nuclear equation of state (EOS) relevant for neutron stars is studied using a Bayesian approach. A set of models based on a density-dependent relativistic mean-field description of nuclear matter is used. The EOS is subjected to minimal constraints based on nuclear saturation properties and a precise calculation in chiral effective field theory. The posterior distributions of the model parameters are used to construct the distributions of various nuclear matter and neutron star properties. The results are found to be compatible with observed data without invoking exotic degrees of freedom.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Nuclear
Yasuhiko Tsue, Constanca Providencia, Joao da Providencia, Masatoshi Yamamura
Summary: This paper focuses on the su(2)-Lipkin model and discovers an unexpected discrepancy between the exact treatment and the conventional RPA method when calculating the excitation energy to the first excited state. To address this issue, the conventional RPA method is renewed and the su(2)-Lipkin model is modified to be applicable to nonclosed shell systems.
INTERNATIONAL JOURNAL OF MODERN PHYSICS E
(2022)
Article
Astronomy & Astrophysics
Edoardo Giangrandi, Violetta Sagun, Oleksii Ivanytskyi, Constanca Providencia, Tim Dietrich
Summary: We propose a model of asymmetric bosonic dark matter with self-repulsion. By studying different distribution regimes, we find that condensed dark matter leads to smaller radius and tidal deformability compared to pure baryonic stars, while the presence of a dark matter halo increases the tidal deformability and total gravitational mass. We impose constraints on the model parameters based on the self-interaction cross section of dark matter and discuss smoking gun evidence of dark matter presence.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Tuhin Malik, Marcio Ferreira, Milena Bastos Albino, Constanca Providencia
Summary: This study analyzes the high-density behavior of nuclear matter using a relativistic mean field description with nonlinear meson interactions. A Bayesian inference technique is used to evaluate the model parameters and their output. The study identifies three distinct classes of equations of state based on the strength of the nonlinear vector field contribution, each correlated with different star properties distributions.
Article
Astronomy & Astrophysics
Marcio Ferreira, Valeria Carvalho, Constanca Providência
Summary: This study successfully extracts the nuclear matter properties from cold beta-equilibrium neutron star matter using deep neural networks. The DNN model achieved high accuracy in the test set and was able to accurately predict the nuclear matter parameters in a real-case scenario involving 33 nuclear models.
Article
Astronomy & Astrophysics
Tuhin Malik, Constanca Providencia
Summary: The possible signatures of hyperons inside neutron stars are discussed using a Bayesian inference framework. Based on nuclear matter and hypernuclei properties, as well as observational information, the general properties of neutron stars are examined. It is found that neutron stars described by equations of state that include hyperons have larger radius and tidal deformability, but smaller speed of sound compared to stars described by nucleonic equations of state. Specific constraints on the possible hyperon content of neutron stars are given based on measurements of mass and radius. The presence of hyperons inside neutron stars is compatible with current observations of pulsars and gravitational wave detection.
Article
Physics, Nuclear
Kauan D. Marquez, Debora P. Menezes, Helena Pais, Constanca Providencia
Summary: By using a relativistic mean-field description with density dependent couplings, the properties of neutron star matter with different compositions are analyzed. The presence of hyperons decreases the fraction of A baryons in the center of the star, while without hyperons, stars with a dominant A baryon composition are possible.
Review
Physics, Nuclear
S. Typel, M. Oertel, T. Klahn, D. Chatterjee, V Dexheimer, C. Ishizuka, M. Mancini, J. Novak, H. Pais, C. Providencia, Ad R. Raduta, M. Servillat, L. Tolos
Summary: CompOSE is an online repository of equations of state (EoS) for use in nuclear physics and astrophysics. It offers a collection of data tables for different EoS types and related physical quantities, software for data extraction and interpolation, and webtools for generating customized EoS tables. This manual is an updated version of the CompOSE service, providing a detailed description and instructions for users.
EUROPEAN PHYSICAL JOURNAL A
(2022)
Article
Astronomy & Astrophysics
Joao Aveiro, Felipe F. Freitas, Marcio Ferreira, Antonio Onofre, Constanca Providencia, Goncalo Goncalves, Jose A. Font
Summary: In this study, the YOLOv5 model is used for detecting binary neutron star coalescence events from gravitational-wave data, achieving high average precision values. The model shows potential for application in first-stage detection alarm pipelines.
Article
Physics, Nuclear
Tuhin Malik, B. K. Agrawal, Constanca Providencia
Summary: An important goal in astrophysics is to understand the equation of state and composition of neutron stars. This study uses the nucleonic direct Urca process as a probe to investigate the high density behavior of nuclear symmetry energy. The results show a strong correlation between the nuclear symmetry energy and neutron star mass, providing valuable constraints on its behavior at high density.
Article
Physics, Nuclear
Lami Suleiman, Morgane Fortin, Julian Leszek Zdunik, Constanca Providencia
Summary: The study revises fits of equations of state using unified tables for neutron star matter, aiming to model macroscopic parameters accurately. By fitting parameters to 52 unified equations of state, properties like mass, radius, tidal deformability, and moment of inertia of neutron stars are compared to ensure the accuracy of the fits. The fit error on macroscopic parameters is found to be small and within the measurement accuracy of current and next-generation telescopes.
Article
Astronomy & Astrophysics
Veronica Dexheimer, Marco Mancini, Micaela Oertel, Constanca Providencia, Laura Tolos, Stefan Typel
Summary: This article presents a combination of two quick guides that summarize relevant information about the CompOSE nuclear equation of state repository. The first guide is aimed at nuclear physicists and provides instructions on how to provide standard equation of state tables, while the second guide is meant for users and describes the basic procedures to obtain customized tables with equation of state data. Several examples are included to help both providers and users of the CompOSE database.
Article
Physics, Nuclear
Tiago Custodio, Helena Pais, Constanca Providencia
Summary: The production of light nuclei, hypernuclei, and heavy baryons in low-density stellar environments is studied using relativistic mean-field models. The presence of both hyperons and A baryons leads to a shift in the dissolution of clusters to higher densities and an increase in their abundance. This effect is more significant at lower charge fractions and higher temperatures.
Article
Astronomy & Astrophysics
Xiaopeng Wang, Jing Li, Jianjun Fang, Helena Pais, Constanca Providencia
Summary: In this study, the properties of nuclear matter in the innermost crust of neutron stars under a strong magnetic field are considered. The density dependence, nonhomogeneous matter, and crust structure are discussed. The results show that a strong magnetic field extends the crust, causing disconnected nonhomogeneous regions and increasing the proton fraction.