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Properties of collective flow and pion production in intermediate-energy heavy-ion collisions with a relativistic quantum molecular dynamics model

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Nuclear Science and Techniques 2024年第1期35卷 155-169页

作者： Si-Na Wei zhao-qing feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The relativistic mean-field approach was implemented in the Lanzhou quantum molecular dynamics transport model(***). Using the ***, the properties of collective flow and pion production were investigated systematically for nuclear reactions with various isospin asymmetries. The directed and elliptic flows of the *** are able to describe the experimental data of STAR Collaboration. The directed flow difference between free neutrons and protons was associated with the stiffness of the symmetry energy, that is, a softer symmetry energy led to a larger flow difference. For various collision energies, the ratio between the π^(-) and π^(+) yields increased with a decrease in the slope parameter of the symmetry energy. When the collision energy was 270 MeV/nucleon, the single ratio of the pion transverse momentum spectra also increased with decreasing slope parameter of the symmetry energy in both nearly symmetric and neutron-rich ***, it is difficult to constrain the stiffness of the symmetry energy with the double ratio because of the lack of threshold energy correction on the pion production.

关键词： Heavy-ion collision Collective flow Pion production Symmetry energy Relativistic mean field

Antiproton production in heavy-ion collisions at subthreshold energies

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Chinese Physics C 2020年第1期44卷 99-104页

作者： zhao-qing feng School of Physics and Optoelectronic Technology South China University of TechnologyGuangzhou 510641China

Within the framework of the Lanzhou quantum molecular dynamics model,the deep subthreshold antiproton production in heavy-ion collisions has been investigated *** elastic scattering,annihilation and charge exchange reactions associated with antiproton channels are implemented in the *** attractive antiproton potential extracted from the G-parity transformation of nucleon selfenergies reduces the threshold energies in meson-baryon and baryon-baryon collisions,and consequently enhances the antiproton yields to some *** calculated invariant spectra are consistent with the available experimental *** primordial antiproton yields increase with the mass number of the colliding ***,annihilation reactions reduce the antiproton production which becomes independent of the colliding ***-flow phenomena of antiprotons correlated with the mean field potential and annihilation mechanism is found by comparing them with the proton *** experiments at the high-intensity heavy-ion accelerator facility(HIAF) in China are discussed.

关键词： antiproton production annihilation reactions anti-flow LQMD model

Potential energy surface and formation of superheavy nuclei with the Skyrme energy-density functional

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Communications in Theoretical Physics 2022年第5期74卷 97-105页

作者： Cheng Peng zhao-qing feng School of Physics and Optoelectronics South China University of TechnologyGangzhou 510640 China

With the Skyrme energy-density functional theory,the nucleus–nucleus potential is calculated and the potential energy surface is obtained with different effective forces for accurately estimating the formation cross sections of superheavy nuclei in massive fusion *** width and height of the potential pocket are influenced by the Skyrme effective forces SkM,SkM^(*),SkP,SIII,Ska,and SLy4,which correspond to the different equations of state for the isospin symmetry nuclear *** is found that the nucleus–nucleus potential is associated with the collision orientation and Skyrme forces.A more repulsive nuclear potential is pronounced with increasing the incompressible modulus of nuclear matter,which hinders the formation of superheavy *** available data in the fusion-evaporation reaction of ^(48)Ca+^(238)U are nicely reproduced with the SkM^(*) parameter by implementing the potential into the dinuclear system model.

关键词： Skyrme force nucleus-nucleus potential energy density functional DNS model

Systematics on production of superheavy nuclei Z=119-122 in fusion-evaporation reactions

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Nuclear Science and Techniques 2021年第10期32卷 59-71页

作者： Fei Niu Peng-Hui Chen zhao-qing feng School of Physics and Optoelectronic Technology South China University of TechnologyGuangzhou 510640China College of Electrical Energy and Power Engineering Yangzhou UniversityYangzhou 225000China

The fusion dynamics of the formation of super-heavy nuclei were investigated thoroughly within the din-uclear system *** Monte Carlo approach was implemented in the nucleon transfer process to include all possible orientations,at which the dinuclear system is assumed to be formed at the touching configuration of dinuclear *** production cross sections of superheavy nuclei Cn,Fl,Lv,Ts,and Og were calculated and compared with the available data from *** evaporation residue excitation functions in the channels of pure neutrons and charged particles were systematically *** combinations of 44 Sc,48;50 Ti,49;51 V,52;54 Cr,58;62 Fe,and 62;64 Ni bombarding the actinide nuclides 238 U,244 Pu,248 Cm,247;249 Bk,249;251 Cf,252 Es,and 243 Am were calculated to produce the superheavy elements with Z¼119?*** obtained that the production cross sections sensitively depend on the neutron richness of the reaction *** structure of the evaporation residue excitation function is related to the neutron separation energy and fission barrier of the compound nucleus.

关键词： Dinuclear system model Fusion-evaporation reactions Superheavy nuclei Cross sections

Nuclear in-medium effects on η dynamics in proton–nucleus collisions

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Nuclear Science and Techniques 2016年第3期27卷 171-175页

作者： Jie Chen zhao-qing feng Jian-Song Wang Institute of Modern Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Kavli Institute for Theoretical Physics Chinese Academy of Sciences

The dynamics of the η meson produced in proton-induced nuclear reactions via the decay of N*(1535)has been investigated within the Lanzhou quantum molecular dynamics transport *** in-medium modifications of the η production in dense nuclear matter are included in the model,in which an attractive η-nucleon potential is *** impact of the η optical potential on the η dynamics is *** is found that the attractive potential leads to the reduction in high-momentum(kinetic energy) production from the spectra of momentum distributions and inclusive cross sections and increasing the reabsorption process by surrounding nucleons.

关键词：量子分子动力学模型质子核碰撞动量分布吸收过程吸引力核反应核物质

Light fragment and neutron emission in high-energy proton induced spallation reactions

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Chinese Physics C 2021年第8期45卷 119-131页

作者： Hui-Gan Cheng zhao-qing feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

The dynamics of high-energy proton-induced spallation reactions on target nuclides of 56Fe,58Ni,107Ag,112d,184W,181Ta,197Au,and 208Pb are investigated with the quantum molecular dynamics transport model motivated by the China initiative Accelerator Driven System(CiADS)in Huizhou and the China Spallation Neutron Source(CSNS)in *** production mechanism of light nuclides and fission fragments is thoroughly analyzed,and the results obtained thereby are compared with available experimental *** statistical code GEMINI is employed in conjunction with a transport model for describing the decay of primary *** the treatment of cluster emission during the preequilibrium stage,a surface coalescence model is implemented into the *** is found that the available data in terms of total fragment yields are well reproduced in the combined approach for spallation reactions both on the heavy and light *** energetic light nuclides(deuteron,triton,helium isotopes etc)mainly created during the preequilibrium stage are treated within the framework of surface coalescence,whereas their evaporation is described in the conventional manner by the GEMINI *** this combined approach,a good overall description of light clusters and neutron emission is obtained,and some discrepancies with the experimental data are *** production of radioactive isotopes in the spallation reactions is also analyzed,i.e.,the 6.8He energy spectra.

关键词： spallation reaction LQMD transport model light charged particle neutron double differential cross section

Dark matter with chiral symmetry admixed with hadronic matterin compact stars

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Chinese Physics C 2022年第4期46卷 1-9页

作者： Si-Na Wei zhao-qing feng School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

Using the two-fluid Tolman-Oppenheimer-Volkoff equation,the properties of dark matter(DM)admixed neutron stars(DANSs)have been *** contrast to previous studies,we find that an increase in the maximum mass and a decrease in the radius of 1.4 M_(⊙)NSs can occur simultaneously in *** stems from the ability of the equation of state(EOS)for DM to be very soft at low density but very stiff at high *** is well known that the IU-FSU and XS models are unable to produce a neutron star(NS)with a maximum mass greater than 2.0 M_(⊙).However,by considering the IU-FSU and XS models for DANSs,there are interactions with DM that can produce a maximum mass greater than 2.0 M_(⊙)and a radius of 1.4 M_(⊙)NSs below 13.7 *** considering a DANS,the difference between DM with chiral symmetry(DMC)and DM with meson exchange(DMM)becomes obvious when the central energy density of DM is greater than that of nuclear matter(NM).In this case,the DMC model with a DM mass of 1000 MeV can still produce a maximum mass greater than 2.0 M_(⊙)and a radius of a 1.4 M_(⊙)NS below 13.7 ***,although the maximum mass of the DANS using the DMM model is greater than 2.0 M_(⊙),the radius of a 1.4 M_(⊙)NS can surpass 13.7 *** the two-fluid system,the maximum mass of a DANS can be larger than 3.0 M_(⊙).Consequently,the dimensionless tidal deformabilityΛCP of a DANS with 1.4 M_(⊙),which increases with increasing maximum mass,may be larger than 800 when the radius of the 1.4 M_(⊙)DANS is approximately 13.0 km.

关键词： chiral symmetry dark matter two-fluid TOV equation neutron star

Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes

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Chinese Chemical Letters 2007年第4期18卷 403-406页

作者： Bing zhao Ya qing feng Yu Kun Li School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and the different dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR, 1H NMR and MS. From their analysis data, it was found that compounds 8, 9, 11 adopted a cone conformation, while compound 10 existed as a mixture of conformations.

关键词： Pyrimidinylthiaalkoxycalixarenes Synthesis Characterization Conformation

Multinucleon transfer dynamics in nearly symmetric nuclear reactions

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Nuclear Science and Techniques 2020年第6期31卷 67-74页

作者： Fei Niu Peng-Hui Chen Hui-Gan Cheng zhao-qing feng School of Physics and Optoelectronic Technology South China University of TechnologyGuangzhou 510641China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100190China

Within the framework of the dinuclear system model,the multinucleon transfer dynamics for nearly symmetric nuclear collisions has been *** reaction mechanism in the systems of 198Pt+198Pt and 204Hg+198Pt was investigated at beam energies around the Coulomb *** was found that the isotopic yields are enhanced with increased incident energy in the domain of proton-rich ***,the production on the neutron-rich side weakly depends on the *** angular distribution with the beam energy was also analyzed in the multinucleon transfer ***-like fragments were produced toward the forward emission with increasing incident *** target-like fragments manifested the opposite trend in the transfer reactions.

关键词： Dinuclear system model Multinucleon transfer reactions Symmetric nuclear collisions Angular distribution