C. Zhong

Measurement of reaction cross section for proton-rich nuclei ( A< 30) at intermediate energies

Radioactive ion beams were produced through the projectile fragmentation induced by 69 MeV/nucleon Ar-36 primary beam on a Be-9 target. Measurements of reaction cross sections (sigma(R)s) for 44 nuclei with A < 30 (mostly proton-rich), on carbon were performed on RIBLL (Radioactive Ion Beam Line in Lanzhou) of HIRFL (Heavy Ion Research Facility in Lanzhou) at intermediate energies around 30 MeV/nucleon by a transmission method. The experimental sigma(R) values for Al-23 and P-27 are abnormally large compared with their neighboring nuclei. Together with the previous experimental facts such as the binding energy and ground state data, it suggests anomalously large matter root-mean-square radii and proton halo structure in Al-23 and in P-27. There is an enhancement for the sigma(R) of F-17 + C-12 compared with the neighboring isotopes. Considering that the ground state of F-17 is 1d(5/2), this can indicate that there is a proton skin in F-17. The calculation of relativistic density-dependent Hartree model (RDDH) shows that the nuclei Al-23 and P-27 may have proton-halo structure and F-17 may have proton-skin structure. The significance of these measurements is discussed

Elliptic flow of phi mesons and strange quark collectivity

Based on a multiphase transport model, we have studied the elliptic flow v{sub 2} of {phi} mesons from the reconstructed K{sup +}K{sup -} decay channel at the top Relativistic Heavy Ion Collider energy at Brookhaven National Laboratory. The dependences of v{sub 2} on transverse momentum p{sub T} and collision centrality are presented and the rescattering effect of {phi} mesons in the hadronic phase is also investigated. The results show that experimental measurement of v{sub 2} for {phi} mesons can retain the early collision information before the {phi} decays and that the {phi} v{sub 2} value obeys the constituent quark number scaling that has been observed for other mesons and baryons. Our study indicates that the {phi} v{sub 2} mostly reflects partonic-level collectivity developed during the early stage of the nucleus-nucleus collision and the strange and light up/down quarks have developed similar angular anistropy properties at the hadronization.

Examining the exotic structure of the proton-rich nucleus {sup 23}Al

The longitudinal momentum distribution (P{sub //}) of fragments after one-proton removal from {sup 23}Al and reaction cross sections ({sigma}{sub R}) for {sup 23,24}Al on a carbon target at 74A MeV have been measured. The {sup 23,24}Al ions were produced through projectile fragmentation of 135A MeV {sup 28}Si primary beam using the RIPS fragment separator at RIKEN. P{sub parallel} is measured by a direct time-of-flight (TOF) technique, while {sigma}{sub R} is determined using a transmission method. An enhancement in {sigma}{sub R} is observed for {sup 23}Al compared with {sup 24}Al. The P{sub parallel} for {sup 22}Mg fragments from {sup 23}Al breakup has been obtained for the first time. FWHM of the distributions has been determined to be 232 {+-} 28 MeV/c. The experimental data are discussed by using the Few-Body Glauber model. Analysis of P{sub //} demonstrates a dominant d-wave configuration for the valence proton in ground state of {sup 23}Al, indicating that {sup 23}Al is not a proton halo nucleus.

Three-particle correlations from parton cascades in Au + Au collisions

Abstract We present a study of three-particle correlations among a trigger particle and two associated particles in Auxa0+xa0Au collisions at s N N = 200 GeV using a multi-phase transport model (AMPT) with both partonic and hadronic interactions. We found that three-particle correlation densities in different angular directions with respect to the triggered particle (‘center’, ‘cone’, ‘deflected’, ‘near’ and ‘near-away’) increase with the number of participants. The ratio of ‘deflected’ to ‘cone’ density approaches to 1.0 with the increasing of number of participants, which indicates that partonic Mach-like shock waves can be produced by strong parton cascades in central Auxa0+xa0Au collisions.

Surveying the nucleon-nucleon momentum correlation function in the framework of quantum molecular dynamics model

Momentum correlation functions of nucleon-nucleon pairs are presented for reactions with C isotopes bombardinga 12 Ctargetwithintheframeworkoftheisospin-dependentquantummolecular dynamics model.The binding-energy dependence of the momentum correlation functions is also explored, and other factors that have an influence on momentum correlation functions are investigated. These factors include momentum-dependent nuclear equations of state, in-medium nucleon-nucleon cross sections, impact parameters, total pair momenta, and beam energy. In particular, the rise and the fall of the strength of momentum correlation functions at lower relative momentum are shown with an increase in beam energy.

Isoscaling behavior in fission dynamics

The fission processes of 112 Sn + 112 Sn and 116 Sn + 116 Sn are simulated with the combination of the Langevin equation and the statistical decay model. The masses of two fission fragments are given by assuming the process of symmetric fission or asymmetric fission by the Monte Carlo sampling with the Gaussian probability distribution. From the analysis to the isotopic/isotonic ratios of the fission fragments from both reactions, the isoscaling behavior has been observed and investigated

Exploring binding energy and separation energy dependences of HBT strength

Abstract Hanbury Brown–Twiss (HBT) results of the nucleon–nucleon correlation function have been presented for the nuclear reactions with neutron-rich projectiles (Be isotopes) using an event-generator, the Isospin-Dependent Quantum Molecular Dynamics model. We explore that the relationship between the binding energy per nucleon of the projectiles and the strength of the neutron–proton HBT at small relative momentum. Moreover, we reveal the relationship between the single neutron separation energy and the strength of the halo neutron–proton HBT. Results show that neutron–proton HBT results are sensitive to binding energy or separation energy.

Longitudinal broadening of near-side jets due to parton cascade

AbstractLongitudinal broadening along the Δη direction on the near side in the two-dimensional (Δφ×Δη) di-hadron correlation distribution has been studied for central Au+Au collisions at n

Breaking of the number-of-constituent-quark scaling for identified-particle elliptic flow as a signal of phase change in low-energy data taken at the BNL Relativistic Heavy Ion Collider (RHIC)

sqrt{s_{NN}}=200

Systematic study of isoscaling behavior in projectile fragmentation by the statistical abrasion–ablation model

nxa0GeV, within a dynamical multi-phase transport model. It was found that longitudinal broadening is generated by a longitudinal flow induced by a strong parton cascade in central Au+Au collisions, to be compared with p+p collisions at n