The status of current constraints on the symmetry energy and generally nuclear equation of state (EoS) from laboratory measurements and astrophysical observations is discussed. Determination of the symmetry energy from data requires knowledge of the EoS of symmetric matter, and the heavy-ion collisions (HIC) are the only means of constraining EoS experimentally at supranormal densities. ...

I present the experimental observables which have been identified by present transport approaches as being sensitive to

the potential among nucleons and explicitly to the nuclear equation of state. This is followed by a discussion

which conclusions can be drawn presently and which variables are presently considered as most promising to come to firm conclusions about the different parts of...

Projectile fragmentation at several hundred MeV/nucleon has been crucial to exploring the world of nuclear physics.

One of the reactions in the projectile fragmentation is the charge-changing reaction cross sections (CCCS), which are the total removal probabilities

of one or more protons during the collisions with target nuclei. The reactions have been used to determine the 𝑟𝑚𝑠 proton radii...

The pygmy dipole resonance (PDR) is a vibrational mode described as the oscillation of a neutron skin against a core symmetric in number of protons and neutrons. The PDR has been the subject of numerous studies, both experimental and theoretical [1,2,3]. Indeed, the study of the PDR has been and still is of great interest since it allows to constrain the symmetry energy, an important...

The nuclear energy density functional (NEDF) theory represents a unified approach to studying properties of nuclei along the nuclide map and the equation of state of nuclear matter. Significant progress has been made in constructing NEDFs using both relativistic and non-relativistic frameworks. NEDFs have primarily been parameterized using experimental data related to ground-state properties...

Quantum phase transitions (QPTs) in atomic nuclei are drastic structural changes in the spectrum that are identified as either shape evolution or crossing shell model configurations in a chain of nuclei as a function of nucleon number. This phenomenon is frequently investigated in nuclear physics, both theoretically and experimentally, where many rare isotope beam facilities investigate a...

In recent years, significant advances have been made in constraining the dense matter equation of state (EOS) from, e.g., multi-messenger astronomy, chiral effective field theory (EFT), novel experimental campaigns such as PREX-II and CREX, and heavy-ion collisions. However, many key questions remain, especially regarding the composition and EOS of the dense matter in the inner cores of heavy...

The meaningful correlations between the zero-sound modes and the stiffness of the nuclear equation of state (EOS) are uncovered in symmetric nuclear matter with the relativistic mean-ﬁeld (RMF) theory. We found that the high-density zero-sound modes merely exist in models with the stiff EOS. While the soft RMF EOS are usually characteristic of the inclusion of the $\omega$-meson...

In my talk I will review the role of hyperons on the properties of neutron stars, discussing the so-called “hyperon puzzle”. I will revise some of the solutions proposed to solve it, and discuss its implications with respect to the most recent measurements of unusually high neutron star masses.

I will present two recent analyses of nuclear data, i.e. flow data from heavy ion collision (HIC) and giant monopole resonances (GMR). These data provide constraints to nuclear matter with an equal number of neutrons and protons. To do so, the model for dense nuclear matter equation of state (EoS) is enriched in order to be sensible to properties close to saturation density, i.e. the curvature...

Loosely bound nuclei are currently at the center of interest in low-energy nuclear physics. The deeper understanding of their properties provided by the shell model for open quantum systems changes the comprehension of many phenomena and offers new horizons for spectroscopic studies of nuclei from the driplines to the valley of $\beta$-stability, for states in the vicinity and above the first...

N.S. Martorana $^1$, G. Cardella$^1$, E.G. Lanza$^1$, A. Barbon$^{1,2}$, A. Castoldi$^3$, G. D’Agata$^{1,2}$, E. De Filippo $^1$, E. Geraci$^{1,2}$, B. Gnoffo$^{1,2}$, C. Guazzoni$^{3}$, C. Maiolino$^{4}$, E.V. Pagano$^{4}$, M. Papa$^{1}$, S. Pirrone$^{1}$, G. Politi$^{1,2}$, L. Quattrocchi$^{1,5}$, F. Risitano$^{1,5}$, F. Rizzo$^{2,4,6}$, P. Russotto$^{4}$, M. Trimarchi$^{1,5}$, C. Zagami...

The isospin symmetry breaking terms of the nuclear interaction is a small part of the whole, while it gives important contributions to some physical observables of nuclear properties. For instance, we showed that the isospin symmetry breaking terms affect the estimation of the slope parameter of the symmetry energy using the neutron-skin thickness and the charge radii difference of the mirror...

The neutron skin (NS) is a phenomenon of an increased neutron to proton density ratio at the nuclear periphery. It is a prominent probe of the nuclear equation of state, connecting nuclear physics and astrophysics. The PREX experiment was the first to determine the NS in $^{208}$Pb through parity-violating electron scattering but had great uncertainty in the resulting NS thickness. The Mainz...

The recent PREX-2 and CREX data on the model-independent extraction of the charge-weak form factor difference ΔF in Pb208 and Ca48 challenge modern nuclear energy density functionals (EDFs) as well as our present understanding on the neutron skin and nuclear symmetry energy. Within the Skyrme-like EDFs, we demonstrate that the isovector spin-orbit interaction can strongly change the ΔF in Ca48...

We investigate the size changing of $2n$, $2p$, and $2d$ during their emission from $^6$He, $^6$Be, $^6$Li, and $^{18}$F in the microscopic calculation framework. The average size of the subsystem in the nucleus is defined with the two-dimensional reduced width amplitude (RWA). The results show that all of these nucleon pairs, including the boundary deuteron($2d$) pair, will happen the size...

Highly dense and isospin asymetric matter is partly out of the reach of nuclear laboratories on Earth but comprises the deepest shells of the highly compact astrophysical objects that are Neutron Stars. An entire field of nuclear astrophysics, which includes multi-messenger astronomy, is devoted to exploring dense matter by observing neutron stars from their birth in core collapse supernovae...

Neutron stars are the sites of the densest, most extreme matter in the Universe, and are natural laboratories in which to explore dense matter physics. I will discuss constraints on the equation of state and the nuclear symmetry energy available through current and future multimessenger observations of neutron star mergers, and how these can complement terrestrial collider experiments.

Short-range nucleon-nucleon correlations (SRC), fluctuations when nucleons form pairs with high relative momentum and small center of mass momentum for short periods of time, provide important information on large relative momentum and short distance properties of nuclear wave functions. This information is important in theoretical models to understand the density dependence of symmetry...

The equation-of-state (EoS) of nuclear matter is of fundamental interest and has been the object of intense theoretical efforts since several decades. The interest is boosted by the fact that it is an important ingredient in modelling astrophysical phenomena such as compact stars and core collapse supernovae. A method to approach the nuclear equation-of-state, practiced since the mid-eighties,...

Charged pion production in HIC is one of the possible probes to study the density dependent symmetry energy. In 2016, the experiments for the measurement of charged pion ratio in neutron-rich and in neutron-deficient Sn+Sn system at the beam energy of E/A=270 MeV were conducted at RIKEN-RIBF.

A constraint on the symmetry energy around the nuclear density of \rho ~ 1.5\rho_0 was given based on...

Heavy-ion collisions at intermediate energies (20-100 MeV/nucleon) are an essential tool for probing the properties of nuclear matter in far-from-equilibrium conditions. Among other topics, they allow the investigation of isospin transport phenomena, which can be interpreted within the framework of the Nuclear Equation of State (NEoS). This area of research holds significant interest due to...

One of the most exciting challenges in modern nuclear physics and astrophysics is to understand the behavior of nuclear matter under extreme conditions. Intermediate energy heavy-ion reactions provide a unique opportunity to enrich our knowledge about the nuclear equation of state (EoS) at sub-saturation densities [1,2]. In particular, the isospin transport in heavy-ion reactions at...

Light nuclear clusters are expected to be ubiquitously present in astrophysical environments and play an important role in different astrophysical phenomena involving ultra-dense baryonic matter, but the estimation of their abundancy demands to correctly estimate the in-medium modification of their binding energy.

In the original measurements, Equilibrium Constants were extracted detecting...

Previous studies at the Cyclotron Institute at Texas A&M University have experimentally shown that neutron-proton equilibration in heavy-ion collisions evolves exponentially [1,2]. The two heaviest fragments originating from the dynamically deformed, excited projectile-like fragment evolve to become more similar as its angle of rotation increases. Results were compared to Constrained Molecular...

The road map for the INDRA & FAZIA collaborations will be presented in this talk, focusing on studies on nuclear symmetry energy and various observables to constraint it. New developements and perspectives will be discussed too.

The Facility for Rare Isotope Beams (FRIB) is at the forefront of research into the fundamental properties of nuclear matter, utilizing heavy ion collisions to explore the physics of rare isotopes and the nuclear equation of state. This talk will provide an overview of the heavy ion collision program at FRIB, highlighting its scientific program and key experimental initiatives including...

On December 25, 2021, the James Webb Space Telescope (JWST), the largest and most complex telescope ever built, was launched from Kourou (Guyana) by an Ariane 5 rocket. Two weeks later, the telescope was fully deployed and by the end of January, it was in orbit around the Lagrange point L2 (1.5 million km from the Earth). Then, the 18 hexagons that constitute the primary mirror were co-phased...

The emission of the pre-equilibrium particles during nuclear collisions at moderate beam energies is still an open question. This influences the properties of the compound nucleus but also changes the interpretation of the quasi-fission process. A systematic analysis of the data obtained by the FAZIA collaboration during a recent experiment with a neutron rich projectile is presented. The full...

The nuclear symmetry energy indicates the binding energy of the nuclear matter depending on the isospin composition. It is a crucial parameter for the structure and stability of dense nuclear matter which exists in astronomical objects such as the neutron stars. Despite the dedicated efforts for the last several decades using the various collision systems in a wide beam-energy range, the...

Since the advent of nuclear physics, traditional bulk properties such as binding energy, shell correction, and deformations have facilitated the prediction of shell closure near the $\beta$-stability region. However, moving away from the stability region towards the dripline, the isospin-asymmetry (neutron-proton asymmetry) starts to dominate. For enhancing the understanding of this region, it...

The nuclear equation of state (EoS) describes the properties of dense nuclear matter, governing the behavior of nuclei, neutron stars, and energetic astrophysical phenomena.

However, our knowledge of the EoS at high densities remains limited due to the lack of direct experimental constraints.

This study combines the analysis of heavy-ion collision data with Bayesian inference to provide...

The isomeric structure and properties in proton-rich nuclides are crucial for determining the path of the rapid proton capture ($rp$)-process. For example, bound nuclei inside the dripline can have unbound isomeric states and change the $rp$-process pathway. The configuration interaction shell model (CISM) is used to investigate nuclei around the $Z=N$ line at the south-west region of...

We investigate how vector-isoscalar and vector-isovector interactions can be determined within the density regime of neutron stars (NSs), while fulfilling nuclear and astrophysics constrains. We make use of the Chiral Mean Field (CMF) model, a SU(3) nonlinear realization of the sigma model within the mean-field approximation, for the first time within a Bayesian analysis framework. We show...

The question of the nuclear symmetry energy is of great importance in physics, with numerous implications for a variety of fields. There exist different approches to solve this question, either experimentally, theoretically, or with astrophysical observations. For the latter, neutron stars are unique laboratories to probe nuclear-rich matter beyond saturation density, and therefore to help...

The properties of neutron-rich nuclear systems are largely determined by the density dependence of the nuclear symmetry energy. Experiments aiming to measure the neutron skin thickness [1,2] and astronomical observations of neutron stars and gravitational waves [3,4] offer valuable information on the symmetry energy at sub- and supra-saturation densities, respectively.

The KIDS theoretical...

We want to review the findings from the 2016 SpiRIT experiment and provide an update on the experiment's status as of spring 2024. We will also introduce upcoming projects utilizing the SAMURAI magnet at RIBF. Additionally, we will showcase the planned upgrades to the RIBF facilities.

The construction of the RAON (Rare Isotope Accelerator complex for ON-line experiments) facility was launched in 2011 as the Rare Isotope Science Project (RISP). The RAON was designed to produce a variety of stable and rare isotope beams to be used for basic science research and applications. The RAON consists of a heavy ion superconducting linear accelerator (SCL2) as the driver for the...

The only way to study the properties of asymmetric nuclear matter at high densities in the laboratory conditions is to investigate the relativistic heavy ion collisions. A complementary source of information are the astrophysical observations and gravitational waves. The degree of compression and pressures achieved during the heavy ion collision depend on the susceptibility of the nuclear...

A new radioactive-ion beam (RIB) accelerator facility, RAON, is under construction in Korea. It consists of two RIB production systems, namely, isotope separation online (ISOL) and in-flight fragmentation (IF) and will eventually combine them to provide more exotic ion beams closer to the neutron drip line.

The large acceptance multi-purpose spectrometer (LAMPS) is one of the experimental...

Heavy-ion collisions and their interpretation by transport model simulations can make a significant contribution to the study of the nuclear EOS, complementary to nuclear structure studies, astrophysical observations and microscopic many-body calculations, since they allow to control to a wide extent the thermodynamical conditions and give information on the composition of the system, in...

The formation of nuclear clusters, which emerge as many-body correlations at sub-saturation densities in nuclear matter, is essential for constructing a reliable equation of state (EOS). Phenomenological models utilizing energy density functionals (EDFs) provide a convenient approach to account for these bound states of nucleons by introducing clusters as additional degrees of freedom (DOF)....

Is it possible to combine a quantum mean-field theory and molecular dynamics within a unique framework for heavy-ion collisions?

Starting from the time-dependent Hartree-Fock scheme and by introducing a dynamical basis of orthogonal fermionic wave functions, we work out a solution to combine the advantages of the two above-mentioned approaches, bypassing a number of usual approximations....

Authors: S. Glässel, V. Kireyeu, G. Coci, V. Voronyuk, M. Winn, J. Aichelin, C. Blume, and E. Bratkovskaya

We present the latest results on the constraints on the equation-of-state (EoS) of strongly interacting hadronic and partonic matter created in heavy-ion collisions from study of the light clusters, hypernuclei and strange hadrons (hyperons and strange mesons). Our study is based on ...

Given an Equation of State (EOS) for neutron star (NS) matter, there is a unique mass– radius sequence characterized by a maximum mass Mmax at radius Rmax. We first show analytically that the Mmax and Rmax scale linearly with two different combinations of the NS central pressure and energy density, by dissecting perturbatively the dimensionless Tolman–Oppenheimer–Volkoff (TOV) equations...

A number of phenomena and signals from compact stars involve transport phenomena in nuclear matter at densities below saturation, where matter is known to be clusterized. This concerns core-collapse supernova dynamics at high temperature, where matter is in a liquid phase and the energy transport is ruled by the interaction of neutrinos with the different nuclear species, but also the...

We investigate the probable existence of dark matter in the interior of neutron stars.

Despite the current state of knowledge, the observational properties of neutron stars have not definitively ruled out the possibility of dark matter. Our research endeavors to shed light on this intriguing mystery by examining how certain neutron star properties, including mass, radius, and tidal...

$\chi$EFT is a powerful framework to construct models for the equation of state of low-density neutron star (NS) matter. However, there are currently only limited probes of NS matter that can reliably be used to test $\chi$EFT and the models it produces. While constraints on bulk NS properties can be inferred from various observables, these properties are mainly sensitive to the NS core, where...

With recent advances in neutron star observations, major progress has been made in determining the pressure of neutron star matter at high density. This pressure is constrained by the neutron star deformability, determined from gravitational waves emitted in a neutron-star merger, and measurements of radii of two neutron stars, using a new X-ray observatory on the International Space Station....

The data-driven Bayesian model averaging is a rigorous statistical approach to combining multiple models for a unified prediction. Compared with the individual model, it provides more reliable information, especially for problems involving apparent model dependence. In this work, within both the non-relativistic Skyrme energy density functional and the nonlinear relativistic mean field model,...

Astrophysical observations of neutron stars allow us to study the physics of matter at extreme conditions which are beyond the scope of any terrestrial experiments. In this work, we perform a Bayesian analysis putting together the available knowledge from the nuclear physics experiments, observations of different X-ray sources, and gravitational wave events to constrain the equation of state...

The Equation of State (EoS) is crucial for understanding the structure of compact objects such as neutron stars. In the conservative hypothesis of a purely nucleonic composition of neutron star matter, the EoS is fully determined in terms of the so-called nuclear matter parameters (NMPs), which, in principle, can be determined from nuclear theory and experiments, though with error bars....

In an ultra-relativistic heavy-ion collision, the geometry of the interaction region is shaped by the (random) positions of the nucleons that populate the colliding nuclei during the ultra-short duration of the collision process. As the created system expands hydrodynamically to the final state, the details of the spatial distributions of these nucleons (clustering, deformations, skin...

Because of strangeness conservation, strange hadrons are produced in pairs through the so-called associated production. As a result, they have small production cross sections and are also not likely to be destroyed after their production in nuclear collisions. With their relatively large masses, their yields in nuclear collisions at energies below their production thresholds in free space are...

The HADES experiment was designed for the exploration of the QCD phase diagram at high baryochemical potential and moderate temperatures as well as for hadron physics with proton and pion beams. In A+A collisions at 1-2 AGeV strangeness production is close to threshold, thus becomes a rare observable being sensitive to the dense baryonic matter that has been created.

The most recent, high...

The ultrarelativistic Pb+Pb collisions are the source of many interesting processes. One of them is creation of the virtual photons by two moving electromagnetic fields generated by charged spectators. Moreover, these photons can excite the Pb nuclei and excite them substantially. The Pb

Our study focuses on the photon induced Pb spectator and its various channels of dexcitation. We...

Through continuous progress in nuclear theory and experiment and an increasing number of neutron-star observations, a multitude of information about the equation of state (EOS) for matter at extreme densities is available. Here, we apply these different pieces of data individually to a broad set of physics-agnostic candidate EOSs and analyze the resulting constraints. Specifically, we make use...

Inferences of the nuclear symmetry energy from heavy-ion collisions are currently based on the comparison of measured observables and transport model simulations. Only the expectation values of observables over all considered events are used in these approaches, however, observables can be obtained event-by-event both in experiments and transport model simulations. By using the light gradient...

We studied alpha-decay half-lives of 84 <= Z <= 92 in the semiclassical WKB approximation frame work using the density-dependent cluster model and the density distribution described by various Korea-IBS-Daegu-SKKU (KIDS) models. Main goal of this work is to find a correlation between alpha-decay half-lives and the stiffness of the symmtery energy. Parameters of KIDS model are determined to...

Recovering the nuclear matter parameters (NMPs), crucial elements in neutron star equations of state for the nucleonic core configuration, is a significant ongoing task in nuclear astrophysics. This involves utilizing various experimental data and astrophysical observations through a Bayesian approach. However, the conventional method of computing the equation of state (EoS) and solving the...

The equation of state of nuclear matter, momentum dependence of the optical potential and in-medium modification of elastic nucleon-nucleon cross-sections have been previously studied by comparing theoretical predictions for collective flows and stopping observables in intermediate energy heavy-ion collisions to experimental data gathered by the FOPI Collaboration[1]. The study is extended to...

In heavy-ion collisions at several hundred MeV/nucleon, a compressed nuclear system is formed to about twice the saturation density and then rapidly expands. It has been a theoretical challenge to extract information about nuclear matter properties such as the EOS of isospin-asymmetric nuclear matter. Since light clusters and heavier fragment nuclei are abundantly produced, they can influence...

An overview of challenges and perspectives offered by correlation measurements at facilities with beams over E/A=100 MeV will be presented. Focus on observables and possible multi-purpose setups, including strategies for using transport model simulations are key for the advance of our community engaged in the study of nuclear matter under extreme conditions and its implications in the most...

Over the past decade, a widely rich variety of data pouring in from laboratory experiments as well as astrophysical observations, including the detection of gravitational waves from binary neutron star mergers and the observations of a subsequent electromagnetic signal have raised new challenges in modelling equation of state of dense matter, and in physics in general. In this contribution, I...

To study the pion production in heavy-ion collisions, we developed the transport model [1] which combines the nucleon dynamics obtained by the antisymmetrized molecular dynamics (AMD) model with a newly developed transport code which we call sJAM. In the previous work [1], we treated the collision terms of the $NN \leftrightarrow N \Delta$ and $\Delta \leftrightarrow N \pi$ processes with the...

Neutron structure and skin thickness in nuclei have been traditionally measured by low-energy scatterings where the nuclei are only gently disturbed. Their precision has been limited by theoretical uncertainties in modeling the nuclear force. Here, we propose an unconventional approach to probe the neutron skin by smashing isobar nuclei completely apart at relativistic energies. We demonstrate...

Giant dipole resonance is a collective excitation mode of the nucleus that exhaust most of the dipole excitation strength. But additionnal low lying dipole strength has been observed in neutron-rich nuclei, called the Pygmy Dipole Resonance (PDR). Both experimental and theoretical studies [1,2,3] have been performed on the PDR, which is often described as the oscillation of a neutron skin...

We have entered the era of multi-messenger nuclear astrophysics; bringing a host of astrophysical observations and nuclear experimental data to collectively measure the properties of neutron star matter and the nuclear force in neutron-rich systems. In order to combine disparate data sets with meaningful uncertainty quantification, over the past decade the statistical inference techniques...

In the last decade the investigation of the $^{132}$Sn and the $^{208}$Pb mass regions has experienced a great progress either experimentally by the advances of new facilities of radioactive ion beams, or theoretically by the development of different theoretical models and effective interactions.

Within the shell model (SM) framework [1], I will expose the calculated spectroscopic...