A Computer Program for Relativistic Multiple Coulomb and Nuclear Excitation

A computer program is presented by which one may calculate the multiple electric dipole, electric quadrupole and magnetic dipole Coulomb excitation with relativistic heavy ions. The program applies to an arbitrary nucleus, specified by the spins and energies of the levels and by all E1, E2 and M1 matrix elements. Nuclear excitation is calculated optionally for monopole, dipole and quadrupole excitations and needs inputs of optical potentials. For given bombarding conditions, the differential cross sections and statistical tensors (useful to calculate gamma-ray angular distribution functions) are computed.Comment: 10 page

The electromagnetic interaction of ultrarelativistic heavy ions

The validity of a delta-function approximation for the electromagnetic interaction of relativistic heavy ions is investigated. The production of e+e- pairs, with electron capture, is used as a test of the approximation.Comment: 11 pages, 3 figure

Coupling of giant resonances to soft E1 and E2 modes in B-8

The dynamic coupling between giant resonance states and "soft", low-energy excitation, modes in weakly-bound nuclei is investigated. A coupled-channels calculation is reported for the reaction 8B + Pb --> p + 7Be + Pb at 83 MeV/nucleon. It is shown that the low-energy response is only marginally modified by transitions to the isovector giant dipole and isoscalar giant quadrupole resonances.Comment: 8 pages, 2 figure

A Coupled-Channels Study of 11Be^{11}Be Coulomb Excitation

We study the effects of channel coupling in the excitation of $^{11}Be$ projectiles incident on heavy targets. The contribution to the excitation from the Coulomb and the nuclear fields in peripheral collisions are considered. Our results are compared with recent data on the excitation of the \halfm state in $^{11}Be$ projectiles. We show that the experimental results cannot be explained, unless very unusual parameters are used.Comment: 8 pages, 2 Postscript figures available upon request, corrected misprints in eqs. 2 and

Quenching of 1+1^+ excitations in the double giant resonance

The electromagnetic excitation of the two-phonon isovector giant dipole resonance in relativistic projectiles incident on heavy targets can be proceed via several intermediate $1^-$ one-phonon giant resonance states. In two step electric dipole transitions the population of $0^+$, $1^+$, and $2^+$ two-phonon states are possible. We calculate the amplitude distribution of $1^-$ excitations with an RPA formalism, and use it to calculate the electromagnetic excitation of two-phonon states in second order perturbation theory and coupled-channels. We show that a conspiracy between angular momentum coupling and the strength of the electromagnetic fields suppresses contributions of $1^+$ states to the total cross sections.Comment: 10 pages, 2 Postscript figures available upon reques

Equivalence of the long-wavelength approximation and the truncated Taylor expansion in relativistic Coulomb excitation

The long-wavelength approximation and the truncated Taylor expansion are frequently used in the theory of relativistic Coulomb excitation to obtain multipole expansions of the interaction. It is shown in this note that these two approximations are exactly equivalent.Comment: 5 page

Double giant resonances in deformed nuclei

We report on the first microscopic study of the properties of two-phonon giant resonances in deformed nuclei. The cross sections of the excitation of the giant dipole and the double giant dipole resonances in relativistic heavy ion collisions are calculated. We predict that the double giant dipole resonance has a one-bump structure with a centroid 0.8 MeV higher than twice energy for the single giant dipole resonance in the reaction under consideration. The width of the double resonance equals to 1.33 of that for the single resonance.Comment: 5 pages, 2 postscript figure

Short-range correlations in two-nucleon knockout reactions

A theory of short-range correlations in two-nucleon removal due to elastic breakup (diffraction dissociation) on a light target is developed. Fingerprints of these correlations will appear in momentum distributions of back-to-back emission of the nucleon pair. Expressions for the momentum distributions are derived and calculations for reactions involving stable and unstable nuclear species are performed. The signature of short-range correlations in other reaction processes is also studied.Comment: Nuclear Physics A, in pres

Breakup of the weakly bound 17F nucleus

The breakup of the radioactive 17F nucleus into a proton and 16O is studied for the reaction 17F + 208Pb --> p + 16O + 208Pb at 65 MeV/nucleon. The possibility of using this reaction as a test case for studying dynamical Coulomb reacceleration effects is assessed. It is shown that the reaction is dominated by elastic nuclear breakup (diffraction dissociation).Comment: 17 figures and 8 figure

Pair production with electron capture in peripheral collisions of relativistic heavy ions

The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z.alpha into account. The dependence on the transverse momentum transfer is studied and the accuracy of the equivalent photon approximation is discussed as a function of the nuclear charge.Comment: 4 postscript figure