Searcharxiv⌕ Search

arXiv · nucl-th/0412044

Surface diffuseness anomaly in heavy-ion potentials for large-angle quasielastic scattering

Abstract

Recent high precision experimental data for heavy-ion fusion reactions at subbarrier energies systematically show that a surprisingly large surface diffuseness parameter for a Woods-Saxon potential is required in order to fit the data. We point out that experimental data for quasi-elastic scattering at backward angles also favor a similar large value of surface diffuseness parameter. Consequently, a double folding approach fails to reproduce the experimental excitation function of quasielastic scattering for the $^{16}$O + $^{154}$Sm system at energies around the Coulomb barrier. We also show that the deviation of the ratio of the quasielastic to the Rutherford cross sections from unity at deep subbarrier energies offers an unambiguous way to determine the value of the surface diffuseness parameter in the nucleus-nucleus potential.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

K. Hagino, T. Takehi, A. B. Balantekin, N. Takigawa. 2004-12-13. Surface diffuseness anomaly in heavy-ion potentials for large-angle quasielastic scattering. https://doi.org/10.1103/physrevc.71.044612

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Bayesian Inference of the Landau Parameter $G'_0$ from Joint Gamow-Teller Measurements

$G'_0$ is the leading-order Landau-Migdal parameter that characterizes the spin-isospin dependent nucleon-nucleon interaction. Consequently, the $G'_0$ is closely related to the Gamow-Teller resonance (GTR), the beta and double-beta decay rates of finite nuclei, the response of hot and dense nucleonic matter that modifies the neutrino-nucleon absorption rates in core-collapse supernovae (CCSNe) and binary neutron star (BNS) mergers, and finally the critical density for pion condensation in neutron stars. In this letter, for the first time, we report the $G'_0$ with quantified uncertainty in the framework of Bayesian inference, using a self-consistent standard Skyrme Random Phase Approximation (RPA) model and joint constraints from experimental GTR measurements on $^{208}\mathrm{Pb}$, $^{132}\mathrm{Sn}$, $^{90}\mathrm{Zr}$. Our extracted $G_0'$ at saturation density is $0.48\pm0.034$, which is close to the prediction of a few existing Skyrme models that consider spin-isospin observables but smaller than the traditional ones extracted from pion-exchange models. The reasons for this deviation, like the value of the nucleon effective mass $\frac{m^*}{m}$ and the density dependence of $G'_0$, are investigated. The density-dependent $G_0'$ values extracted in this work may guide the construction of new energy density functionals that aims to self-consistently describe the dense matter properties in the spin-isospin channel.

nucl-th↗

Accessing zero-point fluctuations in high-energy nuclear collisions

Ultracentral high-energy collisions between identical nuclei are very sensitive to the size and shape of the frozen configuration of nucleons at the instant of the collision, an information that is encoded in the ground state wave functions of the colliding nuclei. The relative standard deviation of the size of the colliding system soon after the collision has recently been inferred from event-by-event fluctuations of the momentum per particle in collisions of $^{208}$Pb nuclei at the LHC, and since a single collision event produces thousands of particles, this information is very precise. We connect this extracted value to the magnitude of the zero-point fluctuations of the radius of the lead nucleus. The value that is extracted from the data is compatible with estimates based on nuclear sum rules, but is overestimated by classical Glauber-type modeling of high-energy collisions. The role of the Pauli principle in suppressing the fluctuations in closed-shell nuclei is underlined. It leads to a distinctive $A$ dependence that could be checked in collisions of smaller systems.

nucl-th↗

Medium effects on neutron star modified and direct Urca cooling rates

We study the effects of in-medium modification of the elementary cooling processes on observable properties of isolated neutron stars. We then deduce the neutron star mass distributions compatible with the cooling analysis and compare with current theoretical models. We conclude that current cooling data require fast direct Urca (DU) cooling, moderated by proton superfluidity, to be active in most neutron stars, and that the DU onset threshold must lie below canonical masses. In that case medium modifications of modified Urca (MU) rates are practically insignificant, but the $nn$ Bremsstrahlung rate plays a dominant role.

nucl-th↗