检索结果-南通市图书馆

Recent progress in two-proton radioactivity

在线全文

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2022年第8期33卷 118-146页

作者： Long Zhou Si-Min Wang De-Qing Fang Yu-Gang Ma Key Laboratory of nuclear physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research center for theoretical nuclear physics NSFC and Fudan UniversityShanghai 200438China

During the last few decades,rare isotope beam facilities have provided unique data for studying the properties of nuclides located far from the beta-stability line.Such nuclei are often accompanied by exotic structures and radioactive modes,which represent the forefront of nuclear research.Among them,two-proton(2p)radioactivity is a rare decay mode found in a few highly proton-rich isotopes.The 2p decay lifetimes and properties of emitted protons hold invaluable information regarding the nuclear structures in the presence of a low-lying proton continuum;as such,they have attracted considerable research attention.In this review,we present some of the recent experimental and theoretical progress regarding the 2p decay,including technical innovations for measuring nucleon-nucleon correlations and developments in the models that connect their structural aspects with their decay properties.This impressive progress should play a significant role in elucidating the mechanism of these exotic decays,probing the corresponding components inside nuclei,and providing deep insights into the open quantum nature of dripline systems.

关键词： Exotic decay Two-proton radioactivity Nucleon-nucleon correlation Experimental and theoretical development

Discussion of thermodynamic features within the PNJL model

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2018年第12期42卷 32-43页

作者：张金利李程明宗红石 Department of physics Nanjing University Joint center for Particle Nuclear Physics and Cosmology State Key Laboratory of theoretical physics Institute of Theoretical Physics CAS

We discuss some thermodynamical features of a QCD system within the two-flavor Polyakov loop ex- tended Nambu Jona-Lasinio （PNJL） model. Several thermodynamical quantities of interest （pressure, energy density, specific heat, speed of sound, etc.） are investigated and discussed in detail with two different forms of Polyakov loop potential. The effective coupling strength G incorporating a quark feedback （quark condensate） through operator product expansion is also discussed, as well as the relationship between color deconfinement and chiral phase crossover. We find that some thermodynamical quantities have quite different behavior for different Polyakov loop potentials. By changing the characteristic temperature To of the pure Yang-Mills feld, we find that when To becomes small, color deconfinement might happen earlier than chiral phase crossover, while their relationship can be determined via some thermodynamical quantities. Furthermore, the behavior of the thermodynamical quantities is quite different in the two different forms of Polyakov loop potential studied. Especially, one of the potentials, specific heat, has two peaks, which correspond to color deconfinement and chiral phase crossover respectively. This interesting phenomenon may shed some light on whether the inflection points at the same temperature or not for lattice QCD and of the chiral condensate and deconfinement transitions happen experimental studies.

关键词： deconfinement specific heat transition temperature

Hypernuclei as a laboratory to test hyperon–nucleon interactions

在线全文

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2023年第6期34卷 5-8页

作者： Yu-Gang Ma Key Laboratory of nuclear physics and Ion-beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai200433China Shanghai Research center for theoretical nuclear physics NSFC and Fudan UniversityShanghai200438China

Directed flow(v_(1))of the hypernuclei ^(3)_(Λ)H and ^(4)_(Λ)H have been observed in mid-central Au+Au collisions at√^(s)NN=3 GeV at RHIC.This measurement opens up a new possibility for studying hyperon–nucleon(Y–N)interaction under finite pressure.In addition,multi-strangeness hypernuclei provide a venue to probe hyperon–nucleon–nucleon(Y–N–N)and even hyperon–hyperon–nucleon(Y–Y–N)interactions.Hypernuclei are important for making connection between nuclear collisions and the equation of state which governs the inner structure of compact stars.

关键词： nucleon addition equation

New type of double‑slit interference experiment at Fermi scale

在线全文

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2023年第1期34卷 175-177页

作者： Yu‑Gang Ma Key Laboratory of nuclear physics and Ion‑beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China Shanghai Research center for theoretical nuclear physics NSFC and Fudan UniversityShanghai 200438China

A new approach that using polarized photon–gluon collisions reported by STAR Collaboration is used to do tomography of the ultrarelativistic nucleus.The collision can be treated as a double-slit experiment at Fermi s... 详细信息

关键词： Fermi double radius

Dynamical chiral symmetry breaking in NJL Model with a strong background magnetic field and Lorentz-violating extension of the Standard Model

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2017年第6期41卷 56-62页

作者：罗翠柏石嵩夏永辉宗红石 Department of physics Nanjing University Joint center for Particle Nuclear Physics and Cosmology State Key Laboratory of theoretical physics Institute of Theoretical PhysicsChinese Academy of Sciences

The Eigenstate Method has been developed to deduce the fermion propagator with a constant external magnetic field. In general, we find its result is equivalent to other methods and this new method is more convenient,especially when one evaluates the contribution from the infinitesimal imaginary term of the fermion propagator. Using the Eigenstate Method we try to discuss whether the infinitesimal imaginary frequency of the fermion propagator in a strong magnetic field and Lorentz-violating extension of the minimal SU（3）×SU（2）×SU（1） Standard Model could have a significant influence on the dynamical mass. When the imaginary term of the fermion propagator in this model is not trivial（√（α-1）eB/3）〈 σ 〈（√（α-1）2eB/3）, this model gives a correction to the dynamical mass.When one does not consider the influence from the imaginary term（σ 〉√（α-1）2eB/3）, there is another correction from the conventional term. Under both circumstances, chiral symmetry is broken.

关键词： NJL strong magnetic field eigenstate method chiral symmetry breaking Lorentz-violation

Calculation of dissociation temperature of quarkonium using Gaussian Expansion Method

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2018年第8期42卷 45-51页

作者：孟琦吴迁程鹏平加伦宗红石 Department of physics Nanjing University Department of physics Nanjing Normal University Joint center for Particle Nuclear Physics and Cosmology State Key Laboratory of theoretical physics Institute of Theoretical PhysicsCAS

The dissociation temperatures of quarkonium states in a thermal medium are obtained in the framework of the quark model with the help of the Gaussian Expansion Method（GEM）.This is the first time this method has been applied to the dissociation problem of mesons.The temperature-dependent potential is obtained by fitting the lattice results.Solving the Schr¨odinger equation with the GEM,the binding energies and corresponding wave functions of the ground states and the excited states are obtained at the same time.The accuracy and efficiency of the GEM provide a great advantage for the dissociation problem of mesons.The results show that the ground states1^1S（0 ）and 1^3S（1 ）have much higher dissociation temperatures than other states,and the spin-dependent interaction has a significant effect on the dissociation temperatures of 1^3S（1 ）and 1^1S0.We also suggest using the radius of the bound state as a criterion of quarkonium dissociation.This can help to avoid the inaccuracy caused by the long tail of quarkonium binding energy dependence on temperature.

关键词： dissociation temperature quarkonium gaussian expansion method

Half-lives of double β^+-decay with two neutrinos

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2015年第1期58卷 38-41页

作者： REN YueJiao REN ZhongZhou Department of physics Nanjing University Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator

nuclear doubleβ--decays with two neutrinos were observed for many years and a systematic law describing the relation between their half-lives and decay energies was also proposed recently[Phys Rev C,2014,89:064603].However,doubleβ+-decay(β+β+)with emission of both two positrons and two neutrinos has not been observed up to date.In this article,we perform a systematic analysis on the candidates of doubleβ+-decay,based on the 2012 nuclear mass table.Eight nuclei are found to be the good candidates for doubleβ+-decay and their half-lives are predicted according to the generalization of the systematic law to doubleβ+-decay.As far as we know,there is no theoretical result on doubleβ+-decay of nucleus154Dy and our result is the first prediction on this nucleus.This is also the first complete research on eight doubleβ+-decay candidates based on the available data of nuclear masses.It is expected that the calculated half-lives of doubleβ+-decay in this article will be useful for future experimental search of doubleβ+-decay.

关键词：半衰期中微子衰变物理学系统正电子候选人法律

Predictions of nuclear charge radii based on the convolutional neural network

在线全文

学校读者我要写书评

暂无评论

nuclear Science and Techniques 2023年第10期34卷 83-90页

作者： Ying-Yu Cao Jian-You Guo Bo Zhou Key Laboratory of nuclear physics and Ion‑beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China School of physics and Optoelectronics Engineering Anhui UniversityHefei 230601China Shanghai Research center for theoretical nuclear physics NSFC and Fudan UniversityShanghai 200438China

In this study, we developed a neural network that incorporates a fully connected layer with a convolutional layer to predict the nuclear charge radii based on the relationships between four local nuclear charge radii. The convolutional neural network(CNN) combines the isospin and pairing effects to describe the charge radii of nuclei with A ≥ 39 and Z ≥ 20. The developed neural network achieved a root mean square(RMS) deviation of 0.0195 fm for a dataset with 928 nuclei. Specifically, the CNN reproduced the trend of the inverted parabolic behavior and odd–even staggering observed in the calcium isotopic chain, demonstrating reliable predictive capability.

关键词： nuclear charge radii Machine learning Neural network

Systematic Calculations of α-Decay Half-Lives Using Microscopic Deformed Potentials

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2012年第7期14卷 588-594页

作者：倪冬冬任中洲 Department of physics Nanjing University Kavli Institute for theoretical physics China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion Accelerator

A new version of the generalized density-dependent cluster model （GDDCM） is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.

关键词： a-decay cluster model half-lives deformed potentials