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Carlos A. Bertulani

Publications and source records attributed to Carlos A. Bertulani.

28 records · Page 2Linked to original sources
arXiv2014

Statistical Theory of Breakup Reactions

We propose alternatives to coupled-channels calculations with loosely-bound exotic nuclei (CDCC), based on the the random matrix (RMT) and the optical background (OPM) models for the statistical theory of nuclear reactions. The coupled channels equations are divided into two sets. The first set, described by the CDCC, and the other set treated with RMT. The resulting theory is a Statistical CDCC (CDCC$_S$), able in principle to take into account many pseudo channels.

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arXiv2013

Role of pairing in the description of Giant Monopole Resonances

We compare the results obtained in the framework of the quasiparticle random phase approximation (QRPA) on top of a Hartree-Fock-Bogoliubov (HFB) with the most recent experiments on giant monopole resonances in Pb, Sn, Zr, Sm, Mo and Cd. Our calculations are fully self consistent and the density dependence of pairing interactions is, for the first time in this framework, properly taken into account. In the particle-hole (ph) channel we employ different Skyrme functionals (SLy5, SkM* and Skxs20) while in the particle-particle (pp) channel we make use of density dependent contact interactions. We introduce in the pp channel the recently proposed contact interactions which take into account the neutron-proton asymmetry. We find that no single parametrization is able to reproduce with sufficient accuracy all the nuclei. Since about two-thirds of the nuclei under investigation are better explained with a soft parametrization, this tends to suggest that the currently accepted picture for the incompressibility might require modifications.

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arXiv2010

The nucleus-nucleus interaction between boosted nuclei

The nucleus-nucleus interaction potential has been studied within the relativistic mean field theory. The systematics of the relativistic effects have been investigated by analyzing the relation between the potential and the bombarding energy as a function of the impact parameter. It is shown that the potential barriers are noticeably sensitive to the bombarding energy for a given impact parameter. At large bombarding energies the slope at the potential edge decreases with the impact parameter. Comparisons with a non-relativistic treatment shows that relativistic effects cannot be ignored at bombarding energies around and larger than 100 MeV/nucleon.

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arXiv2010

Nuclear halo structure and pseudo-spin symmetry

Nuclear halo structure and restoration of relativistic symmetry are studied within the framework of the relativistic Hartree-Fock-Bogoliubov (RHFB) theory. Giant halos as well as ordinary ones are found in Cerium isotopes close to the neutron drip line. Bridged by T=0 {channel}, the restoration of pseudo-spin symmetry (PSS) plays an essential role in stabilizing the neutron halo structures. The Fock terms, especially the $ρ$-tensor couplings, not only play significant role in the PSS restoration but also present substantial contributions to the T=0 {channel}, from which is well demonstrated the necessity of Fock terms.

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arXiv2005

Physics of Ultra-Peripheral Nuclear Collisions

Moving highly-charged ions carry strong electromagnetic fields that act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as {\it ultra-peripheral collisions} (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a $γp$ energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the $ρ^0$, transmutation of lead into bismuth and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of `new physics.'

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arXiv2004

Proton vs. neutron halo breakup

In this paper we show how effective parameters such as effective binding energies can be defined for a proton in the combined nuclear-Coulomb potential, including also the target potential, in the case in which the proton is bound in a nucleus which is partner of a nuclear reaction. Using such effective parameters the proton behaves similarly to a neutron. In this way some unexpected results obtained from dynamical calculations for reactions initiated by very weakly bound proton halo nuclei can be interpreted. Namely the fact that stripping dominates the nuclear breakup cross section which in turn dominates over the Coulomb breakup even when the target is heavy at medium to high incident energies. Our interpretation helps also clarifying why the existence and characteristics of a proton halo extracted from different types of data have sometimes appeared contradictory.

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arXiv2002

Photon Exchange in Nucleus-Nucleus Collisions

The strong electromagnetic fields in peripheral heavy ion collisions give rise to photon-photon and photon-nucleus interactions. I present a general survey of the photon-photon and photon-hadron physics accessible in these collisions. Among these processes I discuss the nuclear fragmentation through the excitation of giant resonances, the Coulomb dissociation method for application in nuclear astrophysics, and the production of particles.

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arXiv1998

The astrophysical reaction 8Li(n,gamma)9Li from measurements by reverse kinematics

We study the breakup of 9Li projectiles in high energy (28.5 MeV/u) collisions with heavy nuclear targets (208Pb). The wave functions are calculated using a single-particle model for 9Li, and a simple optical potential model for the scattering part. A good agreement with measured data is obtained with insignificant E2 contribution.

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arXiv1997

A Study of the Coulomb Dissociation of 8B and the 7Be(p, gamma)8B Reaction

We study the breakup reactions of 8B projectiles in high energy (50 and 250 MeV/u) collisions with heavy nuclear targets (208Pb). The intrinsic nuclear wave functions are calculated using a simple model, as well as a simple optical potential. We demonstrate that nuclear effects are negligible and evaluate the contributions of various (E1, E2 and M1) multipolarities. A good agreement with measured data is obtained with insignificant M1 contribution (at 50 MeV/u) and very small E2 contribution.

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