Wd Tian

Different mechanism of two-proton emission from proton-rich nuclei 23 Al and 22 Mg

Two-proton relative momentum (q(pp)) and opening angle (theta(pp)) distributions from the three-body decay of two excited proton-rich nuclei, namely Al-23 --> p + p + Na-21 and Mg-22 --> p + p + Ne-20, have been measured with the projectile fragment separator (RIPS) at the RIKEN RI Beam Factory. An evident peak at q(pp) similar to 20 MeV/c as well as a peak in theta(pp) around 30 degrees are seen in the two-proton break-up channel from a highly-excited Mg-22. In contrast, such peaks are absent for the Al-23 case. It is concluded that the two-proton emission mechanism of excited Mg-22 is quite different from the Al-23 case, with the former having a favorable diproton emission component at a highly excited state and the latter dominated by the sequential decay process

Isospin effect in statistical sequential decay

Isospin effect of the statistical emission fragments from the equilibrated source is investigated in the frame of statistical binary decay implemented into the GEMINI code, isoscaling behavior is observed and the dependences of isoscaling parameters alpha and beta on emission fragment size, source size, source isospin asymmetry and excitation energies are studied. Results show that alpha and beta neither depends on light fragment size nor on source size. A good linear dependence of alpha and beta on the inverse of temperature T is manifested and the relationship of alpha=4C(sym)[(Z(s)/A(s))(1)(2)-(Z(s)/A(s))(2)(2)]/T and beta=4C(sym)[(N-s/A(s))(1)(2)-(N-s/A(s))(2)(2)]/T from different isospin asymmetry sources is satisfied. The symmetry energy coefficient C-sym extracted from simulation results is similar to 23 MeV which includes both the volume and surface term contributions, of which the surface effect seems to play a significant role in the symmetry energy.

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

Proton-proton correlations in distinguishing the two-proton emission mechanism of 23Al and 22Mg

The proton-proton momentum correlation functions (

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

C_{pp}(q)

Investigation of the thermonuclear 18 Ne(α, p) 21 Na reaction rate via resonant elastic scattering of 21 Na + p

) for kinematically complete decay channels of

Hard-photon flow and photon-photon correlation in intermediate-energy heavy-ion collisions

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Scaling of anisotropy flows in intermediate energy heavy ion collisions

Al

Azimuthal asymmetry of direct photons in intermediate energy heavy-ion collisions

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