Constraining nuclear symmetry energy with the charge radii of mirror-pair nuclei

The nuclear charge radius plays a vital role in determining the equation of state of isospin asymmetric nuclear matter.Based on the correlation between the differences in charge radii of mirror-partner nuclei and the slope parameter(L)of symmetry energy at the nuclear saturation density,an analysis of the calibrated slope parameter L was performed in finite nuclei.In this study,relativistic and nonrelativistic energy density functionals were employed to constrain the nuclear symmetry energy through the available databases of the mirror-pair nuclei^(36)Ca–^(36)S,^(38)Ca–^(38)Ar,and ^(54)Ni–^(54)Fe.The deduced nuclear symmetry energy was located in the range 29.89–31.85 MeV,and L of the symmetry energy essentially covered the range 22.50–51.55 MeV at the saturation density.Moreover,the extracted L_(s) at the sensitivity density p_(s)=0.10 fm^(-3) was located in the interval range 30.52–39.76 MeV.

Optical spectroscopy of CrO and electronic states of the Cr group metal monoxides

All of the experimentally known electronic states of the Cr group metal monoxides(Cr O,Mo O,and WO)have been presented in the paper.The optical spectra of the Cr O molecule have been investigated in the gas phase through a combination of the laser-induced fluorescence(LIF)excitation and single-vibronic-level(SVL)emission spectroscopy in the supersonic expansion.The rotational constants of the vibronic electronic states,including X^(5)Π_(-1)(v=0–3),B^(5)Π_(-1)(v=0–10),and B~5Π_1(v=1,5),and the vibrational constants of the spin–orbit components X^(5)Π_(-1,0,1)have been obtained.The molecular constants of the Mo O and WO molecules have been summarized by reviewing the previous spectroscopic studies,and a comprehensive energy level diagram of the Cr group metal monoxides has been constructed.By comparing the electronic configurations,bond lengths,and vibrational frequencies of all the transition metal monoxides in the ground electronic state,the significance of the relativistic effect in the bonding of the 5d transition metal monoxides has been discussed.The related spectroscopic data of the Cr O molecule are available at https://doi.org/10.57760/sciencedb.j00113.00085.

Nucleus++:a new tool bridging AME and NuBAsE for advancing nuclear data analysis

The newly developed software,Nucleus++,is an advanced tool for displaying basic nuclear physics properties from NubAsE and integrating comprehensive mass information for each nuclide from Atomic Mass Evaluation.Additionally,it allows users to compare experimental nuclear masses with predictions from different mass models.Building on the success and learning experiences of its predecessor,Nucleus,this enhanced tool introduces improved functionality and compatibility.With its user-friendly interface,Nucleus++was designed as a valuable tool for scholars and practitioners in the field of nuclear science.This article offers an in-depth description of Nucleus++,highlighting its main features and anticipated impacts on nuclear science research.

Revisiting the island of hexadecapoledeformation nuclei in the A≈150 mass region:focusing on the model application to nuclear shapes and masses

Based on the potential-energy-surface calculation,the impact of different deformation degrees of freedom on a single-particle structure and binding energies in nuclei around^(152)Nd,located on one of the hexadecapole-deformation islands,is analyzed in a multi-dimensional deformation space.Various energy maps,curves and tables are presented to indicate nuclear properties.The calculated equilibrium deformations and binding energies with different potential parameters are compared with experimental data and other theories.It is found that the inclusion of the hexadecapole deformations,especially the axial one,can improve the theoretical description of both nuclear shapes and masses.In addition,our calculated potential-energy curve shows that a critical deformation-point,β_(2)≈0.4,exists—the triaxial(hexadecapole)deformation effect can be neglectable but the hexadecapole(triaxial)one plays an important role before(after)such a critical point.

Development of a low-background neutron detector array

A low-background neutron detector array was developed to measure the cross section of the ^(13)C(a,n)^(16)O reaction,which is the neutron source for the s-process in AGB stars,in the Gamow window(E_(c.m.)=190±40 keV)at the China Jinping Underground Laboratory(CJPL).The detector array consists of 24^(3)He proportional counters embedded in a polyethylene cube.Owing to the deep underground location and a borated polyethylene shield around the detector array,a low background of 4.5(2)/h was achieved.The ^(51)V(p,n)^(51)Cr reaction was used to determine the neutron detection efficiency of the array for neutrons with energies E_(n)<1 MeV.Geant4 simulations are shown to effectively reproduce the experimental results.They were used to extrapolate the detection efficiency to higher energies for neutrons emitted in the ^(13)C(α,n)^(16)O reaction.The theoretical angular distributions of the ^(13)C(α,n)^(16)O reaction were shown to be important in the estimation of the uncertainties of the detection efficiency.

Ab initio Calculations for Isospin Symmetry Breaking in Nuclear Systems

In the present work,we utilize the approach of the ab initio valence-space in-medium similarity renormalization group(VS-IMSRG)to investigate isospin-symmetry breaking in medium mass nuclei.The adopted nuclear force incorporates charge-symmetry and charge-independence breakings.We focus on computing mirror energies of sd-and pf-shell nuclei and discuss the inuence of single-particle states,particularly those with s-wave character,on weakly bound and unbound nuclear states of sd-shell nuclei.

Studies of Three-body Interaction with Heavy Ion Collisions in the Medium Energy Region

Studies of three-body forces is one of the frontier research topics in astrophysics as well as in nuclear physics.However,it is too difficult to observe it directly in experiment.In order to study it,we can only measure some physical observables which are sensitive to three-body forces.According to theory studies[1],we propose to study three-body interaction by measuring ^(40)Ar+^(51)V collisions in the medium energy region at the CSR External Target Facility(ETF)in Lanzhou.

Design of a Position-Sensitive Time-of-ight Detector for the Bρ-de ned Isochronous Mass Spectrometry at CSRe and SRing

It is well known that the motion of a charged particle with a nonzero emittance in a storage ring is characterized by betatron oscillations in the transverse plane of the ion motion^([1]).The effects of the betatron oscillation on the revolution time has been observed in the isochronous mass measurement experiments in CSRe^([2]).

Simulation of Proton-proton Elastic Scattering at 3.2 GeV/c

The anti-proton annihilation at darmstadt(PANDA)will be a key experiment at the Facility for antiproton and Ion Research(FAIR).One of its main goals is to measure absolute cross section with precision better than 5%.In order to calibrate the PANDA luminosity,the key experiment for Panda luminosity calibartion(KOALA),which is to measure the anti-proton proton elastic scattering,will be carried out at the very beginning of the full run of PANDA.The total cross section(σtot),the ratio of the real to imaginary part of the scattering amplitude(ρ)。

Transverse Momentum Structure of Proton within the Basis Light-front Quantization Framework

We obtain the leading-twist valence quark transverse-momentum-dependent parton distribution functions(TMD PDFs)of quarks in the proton within the basis light-front quantization(BLFQ)framework.Our results are consistent with lattice QCD calculations and the previous BLFQ calculations of the collinear dirtibutions.We also obtain consistency with the So er-type bounds.Within our approach,we nd that six T-even TMDs in the leading twist are all independent of each other,and previously found model-dependent relations do not hold.This is a promising sign that our results are representative of future,more extensive treatments of QCD(Fig.1).

Signature Splitting of g_(7/2)[404]7/2^(+)Bands in^(131)Ba and^(133)Ce

The structure of an odd-A nuclei can be described as even-even core plus an odd number of quasiparticles.In axially deformed odd-A nuclei,strongly coupled rotational bands can be formed when the only quasiparticle occupies high-j.

Rate Constant Determination in the Reaction of Gold ion with Carbonyl Using Single-Atom Chemistry in Gas Phase

The reactions of single gold ion Au^(+)with CO and H_(2)O molecules in gas phase were studied by experiment and calculation.A reaction tube was designed under the steam of the laser sputtering position to destroy the supersonic molecular jet and enhance the collisions between the sputtered metal ions with gas molecules,ensuring the equilibrium reaction conditions.The ionic products were analyzed by a time-of-flight mass spectrometer.

The Reaction ^(55)Mn+^(159)Tb:Preparation for the Synthesis of New Elements

In recent decades,much experimental progress has been made in the synthesis of SHEs and several attempts have been made.However,none of these experiments provide evidence for the successful synthesis of the new elements.In order to produce the new elements with proton number Z=119 or 120,IMP-CAS(Institute of Modern Physics,Chinese Academy of Sciences)constructed the China Accelerator Facility for superheavy Elements(CAFE2).The beams with medium mass,such as ^(50)Ti,^(51)V,^(54)Cr,^(55)Mn.

α Decay of the New Isotope ^(204)Ac

Proton-andα-decay spectroscopy can provide valuable information on the nuclear structure and masses of neutron-de cient isotopes.In 1994,the proton drip line of Ac was reached by the detection of^(207)Ac which was identified via the-decay spectroscopy.Four years later,the neighboring proton-unbound nucleus ^(206)Ac was discov-ered.

Spectroscopic factors of resonance states with the Gamow shell model

We provide an investigation of the spectroscopic factor of resonance states in A=5-8 nuclei,utilizing the Gamow shell model(GSM).Within the GSM,the configuration mixing is taken into account exactly with the shell model framework,and the continuum coupling is addressed via the complex-energy Berggren ensemble,which treats bound,resonance,and non-resonant continuum single-particle states on an equal footing.As a result,both the configuration mixing and continuum coupling are meticulously considered in the GSM.We first calculate the low-lying states of helium isotopes and isotones with the GSM,and the results are compared with that of ab initio no-core shell model(NCSM)calculations.The results indicate that GSM can reproduce the low-lying resonance states more accurately than the NCSM.Following this,we delve into the spectroscopic factors of the resonance states as computed through both GSM and NCSM,concurrently conducting systematic calculations of overlap functions pertinent to these resonance states.Finally,the calculated overlap function and spectroscopic factor of6He(01+)■νp3/2→^(7)He(3/2_(1)-)with GSM are compared with the results from ab initio NCSM,variational Monte Carlo,and Green’s function Monte Carlo calculations,as well as available experimental data.The results assert that wave function asymptotes can only be reproduced in GSM,where resonance and continuum coupling are precisely addressed.

Elastic scattering of ^(13)C and ^(14)C isotopes on a ^(208)Pb target at energies of approximately five times the Coulomb barriers

The elastic scattering angular distributions of ^(13)C at 340 MeV and ^(14)C at 294 MeV and 342 MeV on a ^(208)Pb target,which correspond to approximately five times the Coulomb barriers,were measured at the Radioactive Ion Beam Line in Lanzhou.The data were analyzed within the optical model and continuum-discretized coupled-channels(CDCC)framework,and the results of both calculations could effectively account for the experimental data.The differential cross sections of elastic scattering revealed no particular suppression at the Coulomb nuclear interference peak angles,suggesting that the breakup coupling effects on the elastic scattering angular distributions were negligibly small in this incident energy region.The contributions from the couplings with inelastic states to the elastic cross sections were of minor importance within the angular range covered by these experiments.

Ground-state mass of ^(22)Al and test of state-of-the-art ab initio calculations

The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou.The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 keV.When compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)keV.The excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory.The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.

Toward precision mass measurements of neutron-rich nuclei relevant to r-process nucleosynthesis

The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies. Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron. Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies. In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in r-process calculations. We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples. For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of r-process nuclides.

Precision mass measurements of short-lived nuclides at HIRFL-CSR in Lanzhou

In recent years, extensive short-lived nuclear mass measurements have been carried out at the Heavy- Ion Research Facility （HIRFL） in Lanzhou using Isochronous Mass Spectrometry （IMS）. The obtained mass values have been successfully applied to nuclear structure and astrophysics studies. In this contribution, we give a brief introduction to the nuclear mass measurements at HIRFL-CSR facility. Main technical developments are described and recent results are summarized. Furthermore, we envision the future perspective for the next-generation storage ring facility HIAF in Huizhou.

Precision Mass Measurements of Short-lived Nuclides at the Heavy-ion Storage Ring in Lanzhou

Recent commissioning of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou enabled us to conduct high-precision mass measurements at the Institute of Modern Physics in Lanzhou(IMP). In the past few years, mass measurements were performed using the CSRe-based isochronous mass spectrometry employing the fragmentation of the energetic beams of58 Ni,78Kr,86 Kr,and112Sn projectiles. Masses of short-lived nuclides on both sides of the stability valley were addressed.Relative mass precision of down to 10-6～ 10-7is routinely achieved. The mass values were used as an input for dedicated nuclear structure and astrophysics studies, providing for instance new insights into the rp-process of nucleosynthesis in X-ray bursts. In this contribution, we briefly review the so far conducted experiments and the main achieved results, as well as outline the plans for future experiments.