The cooperation of world-leading experimentalists and theoreticians in the field of strangeness nuclear physics with experts of the neutron star community is the aim of the networking activity THEIA. The main objectives of THEIA were
• the hypertriton puzzle and its implication for fragment formation in heavy ion reactions.
• the study of antihyperons in nuclei by antiproton nucleus...
Recently, a new generation of chiral hyperon-nucleon interaction has been developed [1]. In this
contribution, I will discuss the properties of these interactions and apply them to light hypernuclei.
A special focus will be put on using different chiral orders to obtain reliable uncertainty estimates [2].
[1] J. Haidenbauer, U.-G. Meißner, A. Nogga and H. Le,
Hyperon-nucleon...
The possibility of short distance repulsion applicable inside the cores of neutron stars is incorporated into the hadron equation of state generated by the quark-meson coupling model. Whilst obtaining an incompressibility compatible with data on giant monopole resonance, neutron stars are predicted to have a maximum mass in excess of 2.1 $M_\odot$, even when hyperons are included under...
The behavior of kaon and anti-kaon in dense matter is an important topic, as their nature is closely related to symmetry breaking in low-energy QCD.
The interaction of kaons and anti-kaon with nucleon has been extensively studied with various experiments.These studies found that the Kbar-N interaction in the isospin I=0 channel is sufficient to produce the quasi-bound state Λ(1405).
This...
Bound states caused by attractive $\bar{K}N (I=0)$ interaction, such as $\Lambda(1405)$ and kaonic nuclei, are interesting systems with strangeness.
Many experimental attempts have tried to establish an existence of the lightest kaonic nuclei, "$K^- pp$". However, no clear conclusion was reached. Recently, J-PARC E15 collaboration searched for "$K^- pp$", using the in-flight $K^-...
E15 collaboration at J-PARK reported a clear signal of a KNN quasi-bound state. The width of the state is much larger than theoretical predictions. A series of calculations of the K-pp quasibound state characteristics with different input was performed in order to check, whether it is possible to reach the experimental values.
The speed of sound in the core of neutron stars is a key quantity for providing a characteristic signature of a possible phase transition or the occurance of non-standard degrees of freedom in dense baryonic matter. The first part of this talk presents a status summary of results from a systematic Bayes inference analysis of the equation-of-state based on observational data. In the second part...
Terrestrial experiments, particularly heavy-ion collision experiments, suggest the appearance of strangeness containing particles, such as hyperons, in dense matter. The ultrahigh density core of Neutron Stars is the ideal environment to search for strange matter. Over the past decade, astrophysical observations of Neutron Stars across multiple wavelengths of the electromagnetic spectrum have...
The particle content of the interior of neutron stars is still unknown, especially in the case of very massive stars. It is clear that if hyperons or quarks are present, they will affect the dynamics of the merger of two neutron stars. The impact on the observables and even more the prospects for detectability are possibly very interesting, but also uncertain. In this talk, I will illustrate...
The coalescence of a binary system of neutron stars represents a natural laboratory to study hot and ultra-dense matter. Under these extreme conditions, exotic species like hyperons may be present. In this work, we present a comprehensive study of hyperons in neutron star mergers, focusing on the thermal impact they have on the Equation of State. The presence of the hyperons in a hot dense...
In the emerging field of astrophysics, understanding the intricate nature of neutron stars (NSs) and their equations of state (EoS) remains a challenging task. This talk presents an integrated approach based on deep learning and Bayesian neural networks (BNNs) to unravel the NS composition.
Our research is built upon two key studies. The first exploits BNNs' unique capability to provide...
In recent papers [PLB 837 (2023) 137669 and NPA 1039 (2023) 122795] we showed that all measured (1sΛ, 1pΛ) pairs of Λ binding energies in Λ-hypernuclei 12 ≤ A ≤ 208, can be obtained from a Λ-nucleus optical potential with only two adjustable ΛN and ΛN N parameters, associated with leading linear and quadratic terms in the nuclear density. Consequences of suppressing ΛN N interactions between...
Kaonic atoms X-ray spectroscopy is a unique tool to provide experimental data with consequences going from particle and nuclear physics to astrophysics.
30 years ago kaonic atoms were used to measure the charged kaon mass with unprecedented precision. However, there is still a discrepancy of 60 keV between the two most precise measurements, leading to an error of 16 keV on the charged kaon...
The SIDDHARTA-2 collaboration at the INFN Laboratories of Frascati aims to reinforce the present knowledge on kaonic atoms by performing several measurements on various targets in parallel with the main K-d experiment.
The recents improvements of CdZnTe detectors in terms of energy resolution, stability and efficiency suggested these devices as ideal tools to measure intermediate-mass kaonic...
High precision X-ray spectroscopy of kaonic atoms offers the unique opportunity to investigate the strong interaction (QCD) in the low-energy regime, by allowing to directly access the antikaon-nucleus interaction at threshold. In order to do this, a new dedicated technology of Silicon Drift Detectors (SDDs) has been developed by the SIDDHARTA-2 collaboration, with an optimized geometry and a...
The AMADEUS Collaboration conducted research aimed to experimentally investigate the low-energy K− hadronic interactions with light nuclei like hydrogen, helium, and carbon, in order to provide new constraints to the antikaon-nucleon strong interaction studies in the non-perturbative QDC regime. K− nuclear absorption, both at-rest and in-flight, are explored using the unique low-momentum and...
The measurements of $\pi\Sigma$ mass distributions in the $\gamma p \rightarrow K^{+}\pi\Sigma$ photoproduction reaction [1] probe the energy region of the $\Lambda(1405)$ resonance, just below the $\bar{K}N$ threshold, and provide new challenges for the theoretical models of $\pi\Sigma - \bar{K}N$ coupled channels interactions. Adopting the photoproduction model presented in [2, 3] and the...
Exotic hadronic atoms are a valuable tool to experimentally investigate the
strong interaction described by Quantum Chromodynamics (QCD). With kaonic
hydrogen/deuterium atoms one can directly measure the interaction at threshold and
will be able to extract the antikaon-nucleon scattering lengths at zero energy (no
interpolation to zero energy is necessary as in scattering experiments). The...
We have developed a microscopic model for the $K^-NN$ absorption in nuclear matter [1]. The absorption was described as a meson-exchange process and the primary $K^-N$ interaction strength was derived from the state-of-the-art chiral models. The medium modifications of the $K^-N$ scattering amplitudes due to the Pauli principle were taken into account. The model was applied in calculations of...
We review new insights into baryon structure in relation to the quark model. These insights into baryon structure and its potential for modification in a nuclear medium are then used to motivate the derivation of an energy density functional in the quark meson coupling model. Recent results for nuclear structure obtained in this approach will be presented.
Spontaneous breaking of chiral symmetry in the QCD vacuum is thought to be one of the causes of hadron masses. Many experimental challenges have been made to elucidate the mechanism by precisely measuring the hadron mass in nuclear matter, which is expected to be reduced by the partial restoration of chiral symmetry, known as the nuclear matter effect. To date, however, the mechanism has not...
Pionless Effective Field Theory at Leading order proved to be valuable approach in a study of different properties of $s$-shell $\Lambda$- and $\Lambda \Lambda$- hypernuclei. Recently, it was demonstrated that the inclusion of next-to-leading order (NLO) corrections substantially improve predictive power of this theory in a theoretical study of few-body $A \leq5$ nuclear scattering. In my talk...
Charmed $\Lambda_c$ hypernuclei are investigated in the framework of the deformed Skyrme-Hartree-Fock approach. Their ground-state bulk properties, single-particle energy levels, potential energy curves, as well as the existence limit of charmed hypernuclei are studied, with particular regard to the effects of deformation. $\Lambda_c$ $p$ states are found to be strongly bound, in particular in...
Kaonic nuclear states have been one of the hottest topics in hadron physics for these decades. After many experimental efforts, we finally found strong evidence of the KbarNN state in the Λpn final state via in-flight K- reaction on helium-3 in J-PARC E15. We are now constructing an upgraded solenoid spectrometer system to investigate kaonic nuclear systems further. One direction is...
SIDDHARTA-2 represents a state-of-the-art experiment designed to perform dedicated measurements of kaonic atoms, which are particular atomic configurations composed of a negatively charged kaon and a nucleus. Investigating these exotic atoms provides an exceptional means to comprehend the strong interactions in the non-perturbative regime involving strangeness. At present, the SIDDHARTA-2...
The two-particle momentum correlation function from high-energy nuclear collisions is beginning to be used to study hadron-hadron interaction. Because this observable is sensitive to the low-energy interaction, it is useful to study the nature of the near-threshold resonances and the underlying mechanism of the interaction. The meson-baryon and baryon-baryon interaction in strangeness sector...
In this talk, we will introduce the recent progress of the Sigma(1/2-) state around 1400 MeV. This state is beyond the usual quark model and has been predicted to exist as a pentaquark, compact state, or molecular state. Various experiments have provided evidences for the existence of this state, but it has not been confirmed yet. Therefore, it is crucial to observe this state and determine...
The SPHINX project aims building femtosecond-exposure X-ray holographic cameras for imaging microscopic samples and their internal parts (in-vivo cell elements, viruses and nanorobotic devices) with nanometer resolution. The proposal is based on a new implementation of phase-contrast holography that overcomes the limitations encountered by the absorption-contrast systems, namely the low energy...
There could be a deconfined quark phase at the ultra-high density core of the neutron stars. The nature of the deconfinement transition is a matter of debate. Whether it exhibits a jump in the thermodynamic variables or represents, a crossover is a question addressed in laboratory experiments and compact star observations. A suitable construction of the hybrid equations of state (EoS) can lead...
In this a bit off-topic talk, the history of the VOXES spectrometer will be presented, together with its main characteristics and results.
The VOXES spectrometer was intended to be developed for high precision kaonic atoms but then also other possible applications became appealing.
This is the story of how we moved from the VOXES spectrometer for nuclear physics to the MITIQO project to...
All five KEK and J-PARC two-body $\Xi^-$ capture events in light emulsion nuclei to single $\Lambda$
hypernuclei are consistent with Coulomb-assisted $1p_{\Xi^-}$ nuclear states. The underlying
$\Xi$-nuclear potential is strongly attractive
with nuclear-matter depth $V_{\Xi}\geq 20$ MeV [1], considerably larger than suggested by recent
LQCD, femtoscopy and EFT theoretical studies.
We...