Chen Zhi-Qiang

Possible Experimental Evidence of a Moderate Proton Halo in29S

The total reaction cross sections (TRCSs) of 29S+28Si have been measured at intermediate energies. An obvious enhancement in TRCS of 29S is observed as compared with its neighbouring nuclei. The TRCSs of 29S+28Si are calculated with the modified Glauber theory in the optical limit and few-body approaches. The different factor d as a possible measure of halo appearance is deduced from the experimental and theoretical data. It is well accepted that 27P is a proton halo nucleus. Although not as anomalous as 27P, the different factor d of 29S is obviously larger than that of its neighbouring isotones of N = 13. This result indicates that a moderate proton halo may exist in 29S nucleus. We calculate the total reaction cross sections for 29S with the modified Glauber theory as a function of incident energy and compare the results with those for 27Si which is a core nucleus of 29S. The measured TRCSs of 27Si+28Si can be described to be satisfactory by the modified Glauber theory of the optical limit approach. Although a diffused nuclear density distribution is used, the theories still inadequately predict the experimental TRCSs of 29S+28Si, which further indicates the possibility of proton halo in 29S.

Measurements of Total Reaction Cross Sections for Exotic Nuclei Close to the Proton Drip-line at Intermediate Energies and Observation of a Proton Halo in 27P

Measurements of the total reaction cross sections (sigma (R)) for some proton-rich nuclei (N = 11 - 15 isotones) on a carbon target at intermediate energies have been performed on the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou. A larger enhancement of sigma (R) for P-27 has been observed than for its neighbours. Evidence for a proton halo in P-27 has been revealed in the Glauber analysis of the total reaction cross sections in terms of the difference factor d.

Total reaction cross section measurements at intermediate energy for the proton halo candidate Al-23 and its neighbours

Total reaction cross sections sigma (R) for some proton-rich isotones (N = 10) near Al-23 on a carbon target have been measured at intermediate energies in the experiment performed at the Radioactive Ion Beam Line of the Heavy Ion Research Facility in Lanzhou. The Z-dependence Of sigma (R) shows a remarkable enhancement for Al-23 relative to its neighbours. The difference factor d has been deduced from the measured sigma (R) by using the Glauber or Boltzmann-Uehling-Uhlenbeck models. From the above analysis, a possible one-proton halo structure is suggested for Al-23.

Effects of In-Medium Nucleon-Nucleon Cross Section and Nuclear Density Distribution on the Proton-Nucleus Total Reaction Cross Section *

We present the proton-total reaction cross sections σR by comparing the experimental data with the Glauber model calculation using four sets of nucleon-nucleon cross sections used in literature (free nucleon-nucleon cross sections (NNCS), phenomenological NNCS, Bruckner-type NNCS and Pauli NNCS) and different nuclear densities for symmetric and asymmetric nuclei. For light symmetric target nuclei, the experimental σR data are well reproduced by the former three NNCS with the ground state density distributions of relativistic mean-field theory. On the other hand, for asymmetry heavier target nuclei, the calculations of the σR data depend significantly on the nuclear density distribution at large radius in the low energy region. The experimental σR of these nuclei are well reproduced by the empirical 3 pF density distribution and the in-medium NNCS. The neutron surface distributions are also discussed based on the 3 pF nuclear charge distributions.

Study on Fragments Emission in the 64Ni + 64Ni Reaction at 40 AMeV

The multiplicity of fragments in Fermi energy heavy-ion collisions was experimentally extracted. Compared with the results of calculation using the antisymmetrized molecular dynamics (AMD) model which accounts for the primary fragments only, the results calculated using the AMD together with a statistical decay code GEMINI to account for the deexcitation of excited primary fragments are in better agreement with those extracted from the experiment. This observation indicates that the experimental multiplicity distribution may be significantly different from those of primary fragments.

Parallel Momentum Distribution of 28Si Fragments from 29P

Distribution of the parallel momentum of

Parallel Momentum Distribution of28Si Fragments from29P

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Parallel Momentum Distribution of 28 Si Fragments from 29 P

Si fragments from the breakup of 30.7 MeV/nucleon

Production of light nuclei from Ar-36 and Ar-40 fragmentation at about 60 MeV/nucleon

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Comparison on Scale Effect of Urban Heat Island Defined by Brightness Temperature and Land Surface Temperature

P has been measured on C targets. The distribution has the FWHM with the value of 110.5