Isospin Dependence of Incomplete Fusion Reactions at 25 Mev/a
F. Amorini, G. Cardella, G. Giuliani, M. Papa, C. Agodi, R. Alba, A. Anzalone, I. Berceanu, S. Cavallaro, M. B. Chatterjee, R. Coniglione, E. De Filippo, A. Di … 展开作者
F. Amorini, G. Cardella, G. Giuliani, M. Papa, C. Agodi, R. Alba, A. Anzalone, I. Berceanu, S. Cavallaro, M. B. Chatterjee, R. Coniglione, E. De Filippo, A. Di Pietro, E. Geraci, L. Grassi, A. Grzeszczuk, P. Figuera, E. La Guidara, G. Lanzalone, N. Le Neindre, I. Lombardo, C. Maiolino, A. Pagano, S. Pirrone, G. Politi, A. Pop, F. Porto, F. Rizzo, P. Russotto, D. Santonocito, P. Sapienza, G. Verde
40Ca+40,48Ca,46Ti reactions at 25 MeV/A have been studied using the 4p CHIMERA detector. An isospin effect on the competition between incomplete fusion and dissipative binary reaction mechanisms has been observed. The probability of producing a compound system is observed to be lower in the case of N=Z colliding systems as compared to the case of reactions induced on the more neutron rich 48Ca target. Predictions based on CoMD-II calculations show that the competition between fusion-like and dissipative reactions, for the selected centrality, can strongly constraint the parameterization of symmetry energy and its density dependence in the nuclear equation of state.
Isospin Diffusion and Equilibration for Sn+Sn collisions at E/A=35 MeV
在E/A=35 MeV的束流能量下，用不同的同位旋不对称性碰撞Sn核，测量了平衡态和平衡态速率。利用7 Li和7 Be的镜像核产额，结合112 Sn +124 Sn和124 Sn +112 Sn非对称碰撞与112 Sn +112 Sn和124 Sn +124 Sn对称碰撞的数据，研究了同位旋非对称性的扩散.我们使用这些测量探测中心碰撞中的同位旋平衡，其中核子-核子碰撞被泡利不相容原理强烈阻止。结果是一致的运输理论计算，预测在这些碰撞的透明度程度，但不一致的中间质量的碎片由一个单一的化学平衡源的排放。与ImQMD计算的比较是一致的，在更高的入射能量，提供对密度依赖的对称性能量的约束所获得的结果。
A new isoscalar state in the two-baryon system with mass 2380 MeV and width 80 MeV denoted now $d^*(2380)$ has been detected in the experiments at the Juelich Cooler Synchrotron (COSY). Existence or influence of states with higher isospin is a subject of the experiment for studing of the $π^+π^-$ production in $pp$ collisions. Calculations taking into account isotensor dibaryon resonance in the $ΔN$ with $I(J^p) = 2(1^+)$ provide a good description of the $pp\to ppπ^+π^-$ total and differential cross sections.
Experimental results concerning the dynamical fission of quasiprojectiles in semiperipheral collisions for the system 80 Kr+ 48 Ca at 35 MeV/nucleon are presented. Data have been collected with four blocks of the FAZIA setup in the first physics experiment of the FAZIA Collaboration. The degree of isospin equilibration between the two fission fragments and its dependence on their charge asymmetry is investigated. The data are compared with the results of the AMD model coupled to GEMINI as an afterburner, in order to get hints about the timescale of the process.
Symmetry energy and the isoscaling properties of the fragments produced in $^{40}$Ar, $^{40}$Ca + $^{58}$Fe, $^{58}$Ni reactions at 25 $-$ 53 MeV/nucleon
在统计多重碎裂模型的框架下，研究了25 - 53 MeV/核子的$^{40}$ Ar、$^{40}$ Ca + $^{58}$ Fe、$^{58}$ Ni反应多重碎裂产生的碎片的对称能和等标度性质。从初级（热）和次级（冷）碎片产率分布的等标度参数$α$，作为激发能，同位旋（中子-质子不对称性）和碎片对称能的函数进行了研究。结果表明，等标度参数$α$随激发能的增大和对称能的减小而减小.参数$α$也被观察到随着碎裂系统的同位旋差异的增加而增加。当研究初级碎片到次级碎片的顺序衰变时，作为碎裂系统的激发能和同位旋的函数，对等标度参数的影响很小。然而，对称能对热碎片的同位旋性质有很大的影响。实验观察到的标度参数可以解释的对称性能量，这是显着低于基态核饱和密度附近。结果表明，在远离正常基态核的激发能、密度和同位旋处，热核的性质可能有很大的不同。
Neutron-proton effective mass splitting in neutron-rich matter at normal density from analyzing nucleon-nucleus scattering data within an isospin dependent optical model
It is understood from the recent experimental studies that prompt/resonant breakup, and transfer followed by breakup in the weakly bound $^{6,7}$Li-induced reactions play a significant role in the complete-incomplete fusion (CF-ICF), suppression/enhancement in the fusion cross section around the Coulomb barrier. Investigation of ICF over CF was done by measuring cross sections of the populated residues in the $^{7}$Li-induced reaction on $^{\text{nat}}$Nb target within 3--6.5 MeV/nucleon energy region. Measured excitation functions of different channels were compared with different equilibrium…
We investigate the isospin transport with 40,48 Ca+ 40,48 Ca reactions at 35 MeV/nucleon, measured with the coupling of the VAMOS high acceptance spectrometer and the INDRA charged particle multidetector. Using the quasi-projectile remnant measured with VAMOS and carefully selected light-charged-particles measured in coincidence with INDRA, a reconstruction method is applied to estimate the excited quasi-projectile (QP) on an event-by-event basis. The isospin diffusion is investigated using the isospin transport ratio with the asymmetry $δ$ = (N -- Z)/A of the projectile as an isospin-sensitiv…
Symmetry energy and the isospin dependent equation of state
利用30、40和47 MeV/核子的$^{58}$ Ni + $^{58}$ Ni、$^{58}$ Fe + $^{58}$ Ni和$^{58}$ Fe + $^{58}$ Fe反应的多重碎裂产生的碎片，将等标度参数$α$与基于两种不同的核子-核子有效力Gogny和Gogny-AS相互作用的反对称化分子动力学（AMD）计算结果进行了比较.结果表明，Gogny-AS有效相互作用的选择更符合实验数据，得到$\sim$的对称能为18-20 MeV.观察到的值表明，碎片是在$\sim$ 0.08 fm $^{-3}$的降低密度下形成的。
An investigation of the isospin equilibration process in the reactions $^{58,64}$Ni+$^{58,64}$Ni at two bombarding energies in the Fermi regime ($32\,$MeV/nucleon and $52\,$MeV/nucleon) is presented. Data have been acquired during the first experimental campaign of the coupled INDRA-FAZIA apparatus in GANIL. Selecting from peripheral to semi-central collisions, both the neutron content of the quasiprojectile residue and that of the light ejectiles coming from the quasiprojectile evaporation have been used as probes of the dynamical process of isospin diffusion between projectile and target for…
以对称112 Sn +112 Sn，124 Sn +124 Sn碰撞为参考，在入射能量为E/A=50 MeV的条件下，研究了外围非对称112 Sn +124 Sn，124 Sn +112 Sn系统中的同位旋扩散.等标度分析表明，在这些碰撞中的准弹丸和准目标不实现同位旋平衡，允许评估的同位旋输运率。我们发现，同位旋敏感的实验和理论观测值之间的比较，使用适当选择的比例，允许调查的密度依赖性的非对称项的核物质状态方程。
Rapid fluctuations are observed in the tensor-polarization $p_{zz}$ of deuteron beams forward-transmitted through graphite targets. Unpolarized 9.50 to 18.60\,MeV beams from the Köln tandem accelerator were utilized, and the polarization behind seven 36 to 188\,mg/cm$^{2}$ targets was measured with a polarimeter based on the $^{3}{\rm He}(\vec{d},p)^{4}{\rm He}$ reaction. Due to the chosen relation between the areal target densities and the initial beam energies $E_{\rm in}$, the seven sets of $p_{zz}(E_{\rm in})$ can be combined in a common plot as a function of $E_{\rm in}$. This allows one …
Photonuclear reactions on stable isotopes of cadmium and tellurium at bremsstrahlung end-point energies of 10-23 MeV
Joint Institute for Nuclear Research（联合核研究所）；Institute of Nuclear Physics of the Academy of Sciences of the Republic of Uzbekistan（乌兹别克斯坦共和国科学院核物理研究所）；Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University（莫斯科国立大学斯科别尔琴核物理研究所）；Faculty of Physics of Lomonosov Moscow State University（莫斯科国立大学物理系）；Bogoliubov Laboratory of Theoretical Physics of Joint Institute for Nuclear Research（联合核研究所博戈留博夫理论物理实验室）；Dzhelepov Laboratory of Nuclear Problems of Joint Institute for Nuclear Research（联合核研究所杰列波夫核问题实验室）；Institute of Nuclear Physics, Almaty（阿拉木图核物理研究所）
The validity of impact parameter estimation from the multiplicity of charged particles at low-intermediate energies is checked within the framework of ImQMD model. The simulations show that the multiplicity of charged particles cannot estimate the impact parameter of heavy ion collisions very well, especially for central collisions at the beam energies lower than $\sim$70 MeV/u due to the large fluctuations of the multiplicity of charged particles. The simulation results for the central collisions defined by the charged particle multiplicity are compared to those by using impact parameter b=2 …
Study of the $^{11}$B($^{3}$He,d)$^{12}$C reaction at incident $^{3}$He energy E$_{lab}$ = 25 MeV has been performed at the K-130 cyclotron at the University of Jyväskylä, Finland. Differential cross sections have been measured for the 13.35 MeV state and for the states with excitation energy around 20 MeV. The data were analyzed with the DWBA method. A tentative assignment, 4$^{-}$, is given for the state at 13.35 MeV. For the state at 20.98 MeV, the spin-parity 3$^{-}$ and the isospin T = 0 are assigned for the first time. Our model description of the broad state at 21.6 MeV is consistent wi…
The angular distributions of $^{8}$Be states in the excitation energy region, E$_{x}$ $\ \sim$($16.5-18.2$) MeV, produced in the $^{7}$Li($^{3}% $He,d)$^{8}$Be proton transfer reaction have been measured at the Orsay 14.8$-$MV tandem accelerator for $^{3}$He$^{2+}$ ion bombarding energy, E$_{lab}$ $=20$ MeV, and forward anglular range, $θ_{lab}=5^{\circ}-50^{\circ}$. A high energy resolution detection system composed of a split-pole magnetic spectrometer and a $ΔE-E$,\ position-sensitive drift chamber was used to record the energy spectra of outgoing deuterons. The measured cross section data …
Fragment Isotope Distributions and the Isospin Dependent Equation of State
计算预测了高能核-核碰撞过程中发射的粒子的同位素组成与核物质状态方程（EOS）的不对称项的密度依赖性之间的联系。这种连接的中心112 Sn +112 Sn和124 Sn +124 Sn碰撞在E/A=50 MeV的平衡冻结条件的限制进行了研究。测量的同位素产率比和理论预测的平衡极限之间的比较被用来评估密度依赖的不对称项的状态方程的敏感性。这一分析表明，这种比较可能提供一个机会，以限制EOS的不对称项。
In this paper an attempt was to measure, the excitation functions of $^{169}$Tm($^{12}$C, 4n)$^{177}$Re, $^{169}$Tm($^{12}$C, 5n)$^{176}$Re, $^{169}$Tm($^{12}$C, $α$n)$^{176}$Ta, $^{169}$Tm($^{12}$C, $α$2n)$^{175}$Ta , $^{169}$Tm($^{12}$C, $α$3n)$^{174}$Ta , $^{169}$Tm($^{12}$C, $α$4n)$^{173}$Ta, and $^{169}$Tm($^{12}$C, 2$α$2n)$^{171}$Lu reaction channels populated in the interaction of $^{12}$C projectile with $^{169}$Tm target were considered in order to investigate the mechanisms of complete and incomplete fusion reactions. The theoretically predicted excitation functions using PACE4 code …
A narrow peak near 1870 MeV is observed in the combined invariant-mass spectrum of the systems $ΛK^0_S π^-$, $ΛK^0_S π^+$, $ΛK^- π^-$, and $ΛK^- π^+$ formed in $ν_μ$- and $\bar{ν_μ}$-induced charged-current collisions with free protons, deuterons, and Neon nuclei. Observed width of the resonance is consistent with being entirely due to apparatus smearing. A possible interpretation of the peak is formation and three-body $ΛK π$ decay of an exotic baryon with $I = 3/2$ and $S = -2$.
Based on the Isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, the isotope Sn+Sn reactions at 270 MeV/nucleon are investigated. It is shown that nucleon and meson observables in the Sn+Sn reactions at 270 MeV/nucleon cannot effectively probe the high-density symmetry energy. These observables, however, are sensitive to the curvature of the symmetry energy. It thus sheds light on the study of the high-density behavior of the nuclear symmetry energy by extracting the curvature of the symmetry energy through the interpretation of forthcoming RIBF/RIKEN related data.
