The time evolution of the equilibration process in 208Pb + 110Pd collisions

Rehm, K. E.; Essel, H.G.; Hartel, K.; Kienle, P.; Körner, H. J.; Sperr, P.; Wagner, W.

doi:10.1016/0370-2693(79)90832-3

Cited by 18 publications

(8 citation statements)

References 8 publications

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“…If reaction times are sufficiently large, a gradual enhancement in the production of low energy positrons is expected. However, very long reaction times may be obtained in collisions slightly above the Coulomb barrier, as demonstrated by Rehm et al [32] in lighter collision systems. If this trend persists at even lower bombarding energies, i.e.…”

Section: (A) Positron Spectramentioning

confidence: 91%

The decay of the vacuum in the field of superheavy nuclear systems

et al. 1981

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In the strong Coulomb field of a nucleus or quasimolecule with Z > 172 a change of the QED vacuum has been predicted, signalled by the spontaneous emission of positrons if holes in the K-shell are available. The dynamical semiclassical theory of positron excitation in heavy ion scattering is presented and extended to collisions with nuclear contact. Interference patterns in the energy spectrum of the emitted positrons and, for sufficiently long reaction time T, the emerging of a characteristic line at the position of the lsa-resonance is predicted. The position and width of the lsa-resonance is calculated in dependence on the nuclear configuration, the effect of electron screening is taken into account. Recent experimental indications [1,2] for structures in the spectra of positrons emitted in U-U collisions at energies close to the Coulomb barrier are discussed in terms of spontaneous positron creation. The observed spectra could be explained under the assumption of long lasting nuclear reactions (T >4-10 .2o s) with a cross section in the millibarn region. Various consequences of this interpretation are discussed.

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Section: (A) Positron Spectramentioning

confidence: 91%

The decay of the vacuum in the field of superheavy nuclear systems

et al. 1981

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“…In the limit K--~ 0 the shear of the velocity field vanishes and therefore K tends to zero. From (13), (14) one finds…”

Section: Neck Parametersmentioning

confidence: 98%

“…Rehm et al [13] fitted the mass exchange data of 2~ + 2~ scattering by (53) together with a contribution of FAA(0 ). No explanation is given for the physical origin of the finite width of P(A, A, t =0) in the variable A.…”

Section: Influence Of Initial Conditionsmentioning

confidence: 99%

“…In the following we will assume that it can be described in terms of hydrodynamical equations. Like Rehm et al [13] we start with a Langevin equation for the variable A = A 1 -A 1, s…”

Section: Introductionmentioning

confidence: 99%

“…However, the statistical aspect of the reaction is disregarded. It was not until very recently that the collective and the statistical aspect in mass transfer have been considered simultaneously [13]. For the charge equilibration a collective treatment has mostly been felt to be appropriate [14][15][16], generalising the well-known giant dipole mode to the configuration of two touching nuclei.…”

Section: Introductionmentioning

confidence: 99%

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Inertia effects in the mass transport of heavy ion reactions

Großmann

Krappe

1980

Z Physik A

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Mass transport is described as a damped motion including inertia and a Gaussian stochastic force. The inertia coefficient is estimated in a hydrodynamical model, the damping coefficient by volume dissipation as well as by wall dissipation. Depending on the strength of the restoring force the mass-transfer degree of freedom may show inertia effects. In particular, underdamped motion cannot be excluded. The time development of the mean value (A)t and the variance Ft is given in the overdamped as well as in the underdamped regime. The main effect of the inertia is a slower initial increase of F t. A small-amplitude oscillatory behavior of F~ is possible in a moderately underdamped situation.

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