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Titolo: Giant resonance spectroscopy of Ca40 with the (e,e ' x) reaction (II): Multipole decomposition of 4 piintegrated spectra and angular correlations
Autore: Diesener, H; Helm, U; Huck, V; von NeumannCosel, P; Rangacharyulu, C; Richter, A; Schrieder, G; Stascheck, A; Strauch, S; Ryckebusch, J; Carter, J;
 Indirizzi:
 Tech Univ Darmstadt, Inst Kernphys, D64289 Darmstadt, Germany Tech Univ Darmstadt Darmstadt Germany D64289 D64289 Darmstadt, Germany State Univ Ghent, Dept Subatom & Radiat Phys, B9000 Ghent, Belgium State Univ Ghent Ghent Belgium B9000 Radiat Phys, B9000 Ghent, Belgium Univ Witwatersrand, Sch Phys, ZA2050 Johannesburg, South Africa Univ Witwatersrand Johannesburg South Africa ZA2050 sburg, South Africa
 Titolo Testata:
 NUCLEAR PHYSICS A
fascicolo: 34,
volume: 696,
anno: 2001,
pagine: 293  316
 SICI:
 03759474(200112)696:34<293:GRSOCW>2.0.ZU;2D
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 ISOSCALAR QUADRUPOLE STRENGTH; E,E'N REACTION; COINCIDENCE EXPERIMENTS; ELECTRONSCATTERING; MONOPOLE STRENGTH; MOMENTUMTRANSFER; CROSSSECTIONS; FINESTRUCTURE; FORMFACTORS; PB208;
 Keywords:
 nuclear reaction Ca40(e,e ' p), (e,e 'alpha), E0,=78.183.5 MeV; measured angular correlations of p, alpha decay into lowlying states of K39 and Ar36; Ca40 deduced E0, E1, E2 strength distributions, continuum;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Physical, Chemical & Earth Sciences
 Citazioni:
 58
 Recensione:
 Indirizzi per estratti:
 Indirizzo: von NeumannCosel, P Tech Univ Darmstadt, Inst Kernphys, D64289 Darmstadt, Germany Tech Univ Darmstadt Darmstadt Germany D64289 rmany



 Citazione:
 H. Diesener et al., "Giant resonance spectroscopy of Ca40 with the (e,e ' x) reaction (II): Multipole decomposition of 4 piintegrated spectra and angular correlations", NUCL PHYS A, 696(34), 2001, pp. 293316
Abstract
The present article is the second out of three on a study of the Ca40(e, e'x) reaction discussing the multipole decomposition of the measured cross sections and the analysis of angular correlations. The decomposition of thestrongly overlapping E0, E1 and E2 giant resonance strengths using the (e,e'x; x = p, alpha) reaction in Ca40 is discussed for excitation energies between 10 and about 21 MeV. Two extraction methods are presented based on the variation of the form factors for the different multipoles. The resulting B(E1) strength distribution is in good agreement with (gamma, x) photoabsorption data. The summed B(E2) and B(E0) strength is highly fragmented andspread out over the energy region investigated. Microscopic continuum RPA calculations including the coupling of the basic particlehole states to the lowlying surface vibrations are capable of reproducing the strength distributions quite accurately. Exhaustion of the energyweighted sum rules (EWSR) for the various decay channels is presented. A complete decomposition of E0, E1 and E2 contributions in Ca40 is possible for (e, e'alpha) angular correlations populating the Ar36 ground state. Contrary to expectations, the form factors of isoscalar E0 and E2 strengths in the Ca40(e, e'alpha (0)) reaction exhibit increasing differences towards smaller momentum transfers. Angular correlations for proton decay into lowlying states of K39 are compared to a selfconsistent continuum RPA calculation which allows a systematic description of the strong variations observed as a function of Ca40 excitation energy and momentum transfer. The success implies that direct knockout models of the Ca40(e. e'p) reaction are too simple. Furthermore, the shapes of the angular correlations seem tobe determined largely by the finalstate interaction, in particular by charge exchange reactions in the nuclear medium. (C) 2001 Elsevier Science B.V. All rights reserved.
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Documento generato il 02/04/20 alle ore 00:15:33