Effects of momentum-dependent nuclear potential on two-nucleon correlation functions and light cluster production in intermediate energy heavy-ion collisions

Using an isospin- and momentum-dependent transport model, we study the effects due to the momentum dependence of isoscalar nuclear potential as well as that of symmetry potential on two-nucleon correlation functions and light cluster production in intermediate energy heavy-ion collisions induced by neutron-rich nuclei. It is found that both observables are affected significantly by the momentum dependence of nuclear potential, leading to a reduction of their sensitivity to the stiffness of nuclear symmetry energy. However, the $t∕{}^3\mathrm{He}$ ratio remains a sensitive probe of the density dependence of nuclear symmetry energy.

Figure 1

(Color online) Density dependence of nuclear symmetry energy from the MDI interaction with different $x$ values.

Figure 2

(Color online) Density dependence of total symmetry energy together with contributions from the kinetic energy part as well as the momentum-independent and momentum-dependent potential energy parts from the MDI interaction with (a) $x=1$ and (b) $x=-2$.

Figure 3

(Color online) Density dependence of neutron and proton single-particle potentials at different momenta in asymmetric nuclear matter with isospin asymmetry $\delta =0.2$ for different nucleon effective interactions.

Figure 4

(Color online) Momentum dependence of neutron and proton single-particle potentials in asymmetric nuclear matter with isospin asymmetry $\delta =0.2$ and at different densities for different nucleon effective interactions.

Figure 5

(Color online) (a) Density and (b) isospin asymmetry dependence of nucleon effective mass in asymmetric nuclear matter with isospin asymmetry $\delta =0.2$ and at normal nuclear matter density for the MDYI and MDI interactions.

Figure 6

(Color online) Emission rates of protons and neutrons as functions of time for different nucleon effective interactions.

Figure 7

(Color online) Two-nucleon correlation functions gated on the total momentum $P$ of nucleon pairs using the SBKD interaction with soft (filled squares) or stiff (open squares) symmetry energy. Left panels are for $P<300\text{MeV}∕c$ while right panels are for $P>500\text{MeV}∕c$.

Figure 8

(Color online) Same as in Fig. 7 but using the MDYI interaction with soft (filled squares) or stiff (open squares) symmetry energy.

Figure 9

(Color online) Same as in Fig. 7 but using the MDI interaction with soft (filled squares) or stiff (open squares) symmetry energy.

Figure 10

(Color online) Kinetic energy spectra in the center-of-mass system for deuteron (first row), triton (second row), and ${}^3\mathrm{He}$ (third row) from central collisions of ${}^{52}\mathrm{Ca}+{}^{48}\mathrm{Ca}$ at $E=80\text{MeV}∕\text{nucleon}$ by using the SBKD (first column), MDYI (second column) and MDI (third column) interactions with the soft (solid squares) or stiff (open squares) symmetry energy.

Figure 11

(Color online) The $t∕{}^3\mathrm{He}$ ratio as a function of cluster kinetic energy in the center-of-mass system for different interactions (a) SBKD, (b) MDYI, and (c) MDI with the soft (solid squares) and stiff (open squares) symmetry energies. The lines are drawn to guide the eyes.