Evaporation Residue (ER) cross-sections and ER gated $\gamma$-ray fold distributions were measured for the $^{32}$S + $^{154}$Sm nuclear reaction above the Coulomb barrier at six different beam energies from 148 to 191 MeV. $\gamma$-ray multiplicity and spin distributions were extracted from ER-gated fold distributions. The measured ER cross-sections are compared with the results of both the...
Nuclei in the neighborhood of doubly closed $^{40}Ca$ usually exhibit characteristics of spherical single particle excitations [1] and their excitation spectra are well explained by spherical shell model. However, in Nilsson diagram, the low Ω orbitals from pf shell, especially for $1f_{7/2}$ are sharply down sloping for increasing deformation. Therefore, one may expect deformed or...
In nuclei, protons and neutrons are not uniformly distributed, but rather form sub-structures called nuclear clusters within the nucleus. This has been known since the discovery of the nucleus by Rutherford, but it has not been explicitly taken into account in the standard picture of nuclei in current nuclear physics. For example, it is not known how the magic number that appears in nuclei is...
The pair condensation in a nucleus can be regarded as the “deformation” of the nucleus in the gauge space due to the pairing correlation, thus creating a rotational degree of freedom. The deformation makes it possible to specify orientation angles. This is analogous to the fact that spatial deformation produces rotational modes in real space.
The energy of rotation in real space is written as...
Charge radius is one of the most fundamental properties of a nucleus. However, a precise description of the evolution of charge radii along an isotopic chain is highly nontrivial, as reinforced by recent experimental measurements. In this presentation, a Bayesian neural network (BNN) based approach with six inputs including the proton number, mass number, and engineered features associated...
The generalized parton distributions (GPDs) provide abundant information on the hadron structure such as spin structure and spatial distribution in terms of quark and gluon degrees of freedom and can be accessed through the hard exclusive reactions such as the deeply virtual Compton scattering (DVCS) and deeply virtual meson production. In particular, in the presence of the resonance state of...
Atomic nuclei are complex many-body systems composed of nucleons interacting via strong nuclear force. Understanding nuclear properties from the nucleon-nucleon force is one of the main goals of low-energy nuclear physics. Like other quantum many-body problems, the structure of atomic nuclei can be effectively solved using configuration-interaction methods. One such method that is very...
This talk explores the effect of dark matter, captured by the strong gravity and high density of neutron stars, on the equation of state (EoS) of neutron stars. We establish a theoretical framework incorporating dark matter interactions and demonstrate potential modifications in the neutron star EoS. These theoretical modifications allow us to explore potential constraints on the properties of...
The 6He nucleus, as the lightest halo nucleus described well by an alpha particle and two weakly bound neutrons, which can be used as a reference for understanding other complex halo nuclei. In order to investigate the continnum effect of 6He excited state (2+) on elastic scattering and further explore the 6He halo structure and the correlation of two neutrons within 6He, the 6He + p...
We are attempting to derive the proton and neutron distribution radii by simultaneous measurements of the interaction cross sections and the charge-changing cross sections. The relationship between the proton distribution radius and the charge-changing cross section can be intuitively understood through geometric considerations. However, previous studies have revealed that the charge-changing...
The beta-delayed gamma-ray spectroscopy of neutron-rich Ru isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN. The beta-decay schemes of these nuclei are established with the use of prompt-prompt and prompt-delayed gamma-gamma-coincidence measurement by EURICA -ray detection array. The systematic trends of low-lying states and their implications on single-particle orbit...
In this work, we have studied the quartet correlations in the cold infinite symmetric nuclear matter. The hierarchical structure of in-medium cluster formations has been investigated. We have extended the Bardeen-Cooper-Schrieffer-type variational wave function to the systems also with quartet correlations, and discussed how various physical properties will be modified by the quartet...
Neutron stars are known to be one of the densest objects in the universe.
Information on condition in extreme dense matter, which is impossible to measure in the terrestrial experiments, can be obtained through astrophysical observation data.
In particular, the observation results from neutron stars are very useful to constraint the nuclear equation of state (E0S) at high densities.
There...
In some nuclei, a phenomenon called double beta decay, in which two nucleons simultaneously undergo beta decay, is known to occur rarely. In this case, two neutrinos are emitted. Neutrinos may be Majorana particles, which do not distinguish between particles and antiparticles among Fermi particles. In that case, double beta decay without neutrino emission ($0\nu\beta\beta$) may occur. If the...
Double-beta ($\beta\beta$) decay is one of the rarest second-order weak interaction processes with two major decay modes: two-neutrino ($2\nu$) and neutrinoless ($0\nu$). Mayer [1] first introduced the $2\nu\beta\beta$ decay process as a nuclear disintegration with the simultaneous emission of two electrons and two antineutrinos. This process is allowed by lepton number conservation. The study...
The thickness of the $^{11}$B target was determined by using $^{11}$B(p,p$_{0})$ elastic reaction. The proton beams were accelerated up to the energy range from 1.1 - 1.9 MeV by the Pelletron 5SDH-2 accelerator at Hanoi University of Science. The measured $^{11}$B target thickness is 65.45 ± 3.78 $\mu g/cm^2$, lower than the value of 74 $\mu g/cm^2$ from the target supplier. This result...
Nuclei near shell-closed remain a topic of immense interest in nuclear structure research for investigating different aspects of single particle and collective excitation. We have systematically investigated nuclei in the 90-mass region using Indian National Gamma Array (INGA) [1]. The level schemes of most of the isotopes in this region are dominated by single particle excitations, which...
Density distributions tell us the characteristics of nuclei, such as the nuclear size and nuclear skin structure.
Both proton and neutron density distributions can be acquired by proton elastic scattering at two different intermediate energies such as 200 and 300 MeV/u.
For stable nuclei, proton beam and targets of stable nuclei are used.
Inverse kinematics are used for short-lived nuclei,...
Jaewon Kim, Jeong-Yeon Lee, Myung-Ki Cheoun
Department of Physics and OMEG Institute, Soongsil University, Seoul 07040, Korea
The nuclear shell model is a traditional approach for describing and predicting the nuclear properties. It is based on the idea that nucleons occupy shells in the nucleus and interact with each other through a residual two-body interaction. The Gamow shell model...
The charge radius is one of the most fundamental quantities concerning nuclear structure. Recent advancements in high-precision spectroscopic measurements utilizing isotope shifts have provided accurate experimental data on the second-order moments of charge distribution, including isotopes in regions of proton and neutron excess. However, there is no precise theoretical calculation that can...
Nuclear data play an important role in various scientific fields. However, the generation of nuclear data entails enormous human and time costs.
Recently, attempts have been made to solve this problem by using machine learning to generate nuclear data. We aim to generate accurate nuclear data at low cost by combining nuclear reaction models with machine learning.
In this presentation, we...
The equation of state (EoS) of dense matter, such as EoS for neutron stars, remains an open question as it has not yet fully been established. To gain insights into the structure of dense stellar objects, we could rely on experimental information provided by heavy ion collisions. These collisions serve as terrestrial experiments that offer valuable data on the EoS. Transport models, in...
We have designed and upgraded the focal plane polarimeter 2nd-FPP to improve the position and angle resolution. Four MWDCs were newly introduced. The experiment with protons of polarization $P$=0.99 by p-C elastic scattering at 65 MeV was performed at RCNP in order to evaluate the overall performance. The position resolution of about 0.34 mm has been achieved, which is about two orders of...
Neutron-rich nuclei near the neutron number 20 are known to exhibit exotic structure, such as shape deformation of their ground states, contrary to a spherical shape expected from the conventional magicity for the neutron shell. The mass region is called the “island of inversion” and a variety of experimental works has been devoted to study it. To unravel the mechanism to generate the “island...
Understanding nuclear forces is necessary to describe nuclear phenomena, and recently it has become clear that three-nucleon forces, which act between three nucleons, are also essential. We are planning to measure the spin correlation coefficient, one of the spin observables, from deuteron-proton elastic scattering for gathering accurate information on three-nucleon forces.
We use a polarized...
We, the nSHE Research Group, are searching for new elements beyond element 118 (oganesson), i.e. element 119, at RIKEN. The probability of producing superheavy elements by fusion reactions is extremely low. Therefore, it is crucially important to determine the optimal experimental conditions to maximize the production rate, especially by predicting the optimum incident energy that maximizes...
We search for the Electric Dipole Moment (EDM) of Xe atoms using a technique of an artificial-feedback nuclear spin maser. In this study, $^{129}$Xe and 131Xe are used to deduce the isotope-differential EDM as well as to work as comagnetometry. The isotope-differential EDM is deduced from the difference of the precession frequency between $^{129}$Xe and $^{131}$Xe under a magnetic field and...
Rare Isotope Accelerator complex for ON-line experiments (RAON) is currently under construction in Korea. The low-energy experimental facilities in RAON include the Korea Broad Acceptance Recoil spectrometer and Apparatus (KoBRA) and the Nuclear Data Production System (NDPS). One of the objectives at RAON is to provide rare isotope and stable ion beams with a wide energy range, up to a few...
An isomeric state of 45Cr with an excitation energy of 107 keV is of much interest for its nuclear structure in terms of the isospin symmetry. The mirror nucleus of 45Cr, 45Sc, has an isomeric state. The isomeric state of 45Sc (Jπ = 3/2+, Ex = 12.4 keV, T1/2 = 325.8 ms), has been well investigated. However, the half-life of the isomeric state of 45Cr was not measured. In the previous research,...
The mass measurement of proton-rich unstable nuclei in the vicinity of 47Fe has been performed utilizing the TOF-Bρ method with BigRIPS and OEDO-SHARAQ spectrometer at RIBF. In this measurement, the secondary beam included several nuclei with isomeric states in the pf-shell region. The isomer tagging provides us exact particle identification (PID) like a unique fingerprint. Moreover, the...
The study of the p-process is of paramount importance in unraveling the origin of heavy elements in the universe. To describe the entire p-nuclei nucleosynthesis process, a comprehensive reaction network involving over ten thousand nuclear reactions is required, and accurate measurements of some key reaction cross sections are essential for determining reaction rates. 102Pd is one of the more...
Si detectors are extensively applied in the measurement of charged particles produced in fusion reactions. To achieve a relatively low-cost charged-particle detection with the position sensitivity, we have developed a mosaic-type array based on Si photodiodes (Hamammatsu S13955-01). Its high modularity allows one to modify the geometric configuration of the array according to specific...
The permanent electric dipole moment (EDM) of elementary particles is a physical quantity that reflects CP symmetry breaking, and is being explored. In particular, it is theoretically suggested that electron EDMs are amplified as atomic EDMs in heavy elements. In this project, we aim to achieve high-precision EDM measurement using francium (Fr) atoms trapped by laser cooling technique. Toward...
In this presentation, the current status of a comagnetometer which is dedicated
to search for the permanent electric dipole moment of the electron (eEDM) using
francium atoms is discussed. The designed comagnetometer consists of laser-cooled
Rb-87 and Cs-133 atoms trapped simultaneously in an optical lattice in order to
observe the effects of Zeeman shift and vector light shift...
A variety of unstable nuclear beams with atomic numbers (Z) up to 92 can be produced by the projectile fragmentation and in-flight fission from high intensity U beams at RIBF. Recently, it was found that 234−238Np can be created by a proton pickup reaction on 1GeV/nucleon 238U beam. Owing to the recent developments of the high-Z beams at BigRIPS, energy dependence of the proton pickup reaction...
