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A Collaboration M. Makek P. Achenbach C. Ayerbe Gayoso C. Barbieri J. C. Bernauer R. B?hm D. Bosnar A. Denig M. O. Distler I. Fri??i? C. Giusti H. Merkel U. Müller L. Nungesser J. Pochodzalla S. Sanches Majos B. S. Schlimme M. Schwamb Th. Walcher 《The European Physical Journal A - Hadrons and Nuclei》2016,52(9):298
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C. Giusti F. D. Pacati M. Schwamb S. Boffi 《The European Physical Journal A - Hadrons and Nuclei》2007,33(1):29-38
Results for the cross-sections of the exclusive 16O(e, e'pn)14N and 16O(γ, pn)14N knockout reactions are presented and discussed in different kinematics. In comparison with earlier work, a complete treatment
of the center-of-mass (CM) effects in the nuclear one-body current is considered in connection with the problem of the lack
of orthogonality between initial bound and final scattering states. The effects due to CM and orthogonalization are investigated
in combination with different treatments of correlations in the two-nucleon overlap function and for different parametrizations
of the two-body currents. The CM effects lead in super-parallel kinematics to a dramatic increase of the 16O(e, e'pn) cross-section to the 12
+ excited state (3.95MeV) of 14N . In all the situations considered the results are very sensitive to the treatment of correlations. A crucial role is played
by tensor correlations, but also the contribution of long-range correlations is important. 相似文献
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M. Schwamb S. Boffi C. Giusti F.D. Pacati 《The European Physical Journal A - Hadrons and Nuclei》2003,17(1):7-10
The influence of the mutual interaction between the two outgoing nucleons (NN-FSI) in the 16O(e, e'pp) reaction has been investigated. Results for various kinematics are discussed. In general, the effect of NN-FSI depends on
kinematics and the chosen final state in the excitation spectrum of 14C.
Received: 19 December 2002 / Accepted: 6 February 2003 / Published online: 15 April 2003 相似文献
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H. Backe P. Graffé D. Habs M. Hies Ch. Illgner H. Kunz W. Lauth H. Schöpe P. Schwamb W. Theobald P. Thörle N. Trautmann R. Zahn 《Hyperfine Interactions》1993,78(1-4):35-45
An ultra-sensitive laser spectroscopic method has been developed for the hyperfine spectroscopy of short-lived isotopes far off stability produced by heavy ion induced nuclear reactions at very weak intensity (> 1/s). It is based on resonance ionization spectroscopy in a buffer gas cell with radiation detection of the ionization process (RADRIS). As a first on-line application of RADRIS optical spectroscopy at242fAm fission isomers is in progress at the low target production rate of 10/s. The resonance ionization has been performed in two steps utilizing an excimer dye laser combination with a repetition rate of 300 Hz. The first resonant step proceeds through terms which correspond to wavelengths of 466.28, 468.17 or 426.56 nm; the second non-resonant step is achieved with the 351 nm radiation of the excimer laser itself, running with XeF. The frequency scans of the tuneable dye laser at 466.28 and 468.17 nm exhibit broad resonance ionization signals, the latter with a large isotope shift between242fAm and243Am which is in accordance with the large quadrupole moment of the242fAm fission isomer.Work supported by the Bundesministerium für Forschung und Technologie under contract 06 MZ 188 I. 相似文献
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E.M.?Darwish H.?Arenh?velEmail author M.?Schwamb 《The European Physical Journal A - Hadrons and Nuclei》2003,17(4):513-517
The contribution of incoherent single-pion photoproduction to the spin response of the deuteron, i.e., the asymmetry of the total photoabsorption cross-section with respect to parallel and antiparallel spins of photon and deuteron, is calculated over the region of the
-resonance with inclusion of final-state NN and
rescattering. Sizeable effects, mainly from NN rescattering, are found leading to an appreciable reduction of the spin asymmetry. Furthermore, the contribution to the Gerasimov-Drell-Hearn integral is explicitly evaluated by integration up to a photon energy of 550 MeV. Final-state interaction reduces the value of the integral to about half of the value obtained for the pure impulse approximation.Received: 14 February 2003, Revised: 10 April 2003, Published online: 1 July 2003PACS:
11.55.Hx Sum rules - 13.60.Le Meson production - 24.70.+s Polarization phenomena in reactions - 25.20.Lj Photoproduction reactionsE.M. Darwish: Present address: Physics Department, Faculty of Science, South Valley University, Sohag, Egypt. 相似文献
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An explicit evaluation of the spin asymmetry of the deuteron and the associated Gerasimov-Drell-Hearn sum rule is presented which includes photodisintegration, and single and double pion and eta production as well. Photodisintegration is treated with a realistic retarded potential and a corresponding meson exchange current. For single pion and eta production the elementary operator from MAID is employed, whereas for double pion production, an effective Lagrangian approach is used. A large cancellation between the disintegration and the meson production channels yields for the explicit GDH integral a value of 27.31 microb to be compared to the sum rule value 0.65 microb. 相似文献
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A model is developed for the hadronic interaction in the two-nucleon system above pion threshold which is based on meson, nucleon and Δ degrees of freedom and which includes full meson retardation in the exchange operators. For technical reasons, the model allows maximal one meson to be present explicitly. Thus the Hilbert space contains besides NN and NΔ also configurations consisting of two nucleons and one meson. For this reason, only two- and three-body unitarity is obeyed, and the model is suited for reactions in the two-nucleon sector, where only one pion is produced or absorbed. Starting from a realistic pure nucleonic retarded potential, which had to be renormalized because of the additional π and Δ degrees of freedom, a reasonable fit to experimental NN-scattering data could be achieved. 相似文献
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Giusti C. Pacati F. D. Schwamb M. Boffi S. 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):209-220
The treatment of the Δ-current and its contribution in the exclusive 16O (e, e'pp)14C and 16O (γ, pp)14C knockout reactions are investigated in combination with the effects of correlations. Different parametrizations of the effective
Δ-current and different treatments of correlations in the two-nucleon overlap function are considered. The results are presented
and discussed for a suitable choice of kinematics. It is found that the investigation of different mutually supplementing
kinematics is necessary to resolve the uncertainties in the theoretical ingredients and extract clear and unambiguous information
on correlations. 相似文献