The coupling of the giant quadrupole resonance to valence-space configurations is shown to be the origin of the formation of low-lying quadrupole-collective structures in vibrational nuclei with ...symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. For the first time experimental evidence for this picture is obtained from electron- and proton scattering experiments on the nucleus ^{92}Zr that are sensitive to the relative phase of valence-space amplitudes by quantum interference.
An overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated ...Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.
The one-quadrupole phonon excitation of mixed symmetry, the 2+1,ms state, is a fundamental building block of nuclear structure. This article gives a summary of our recent experimental research on ...this excitation mode in the A 90 and A 130 mass regions.
The one-quadrupole phonon excitation of mixed symmetry, the 2+1,ms state, is a fundamental building block of nuclear structure. This article gives a summary of our recent experimental research on ...this excitation mode in the A =90 and A =130 mass regions.
The coupling of the giant quadrupole resonance to valence space configurations is shown to dominantly contribute to the formation of low-lying quadrupole collective structures in vibrational nuclei ...with symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. Experimental evidence is obtained from electron- and proton scattering experiments on the nucleus 92Zr that are directly sensitive to the relative phase of valence space amplitudes by quantum interference.
The coupling of the giant quadrupole resonance to valence space configurations is shown to dominantly contribute to the formation of low-lying quadrupole collective structures in vibrational nuclei ...with symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. Experimental evidence is obtained from electron- and proton scattering experiments on the nucleus super(92)Zr that are directly sensitive to the relative phase of valence space amplitudes by quantum interference.
Background: The B(E2) transition strength to the 2+_2 state in 94Zr was initially reported to be larger by a factor of 1.63 than the one to the 2+_1 state from lifetime measurements with the ...Doppler-shift attenuation method (DSAM) using the (n,n'gamma) reaction E. Elhami et al., Phys. Rev. C 75, 011301(R) (2007). This surprising behavior was recently revised in a new measurement by the same group using the same experimental technique leading to a ratio below unity as expected in vibrational nuclei. Purpose: The goal is an independent determination of the ratio of B(E2) strengths for the transitions to the 2+_(1,2) states of 94Zr with inelastic electron scattering. Method: The relative population of the 2+_(1,2) states in (e,e') reactions was measured at the SDALINAC in a momentum transfer range q = 0.17 - 0.51 fm^(-1) and analyzed in plane-wave Born approximation with the method described in A. Scheikh Obeid et al., Phys. Rev. C 87, 014337 (2013). Results: The extracted B(E2) strength ratio of 0.789(43) between the excitation of the 2+_1 and 2+_2 states of 94Zr is consistent with but more precise than the latest (n,n'gamma) experiment. Using the B(E2) transition strength to the first excited state from the literature a value of 3.9(9) W.u. is deduced for the B(E2; 2+_2 -> 0+_1) transition. Conclusions: The electron scattering result independently confirms the latest interpretation of the different (n,n'gamma) results for the transition to the 2+_2 state in 94Zr.
Background: Mixed-symmetry 2+ states in vibrational nuclei are characterized by a sign change between dominant proton and neutron valence-shell components with respect to the fully symmetric 2+ ...state. The sign can be measured by a decomposition of proton and neutron transition radii with a combination of inelastic electron and hadron scattering C. Walz et al., Phys. Rev. Lett. 106, 062501 (2011). For the case of 92Zr, a difference could be experimentally established for the neutron components, while about equal proton transition radii were indicated by the data. Method: Differential cross sections for the excitation of one-phonon 2+ and 3- states in 92Zr have been measured with the (e,e') reaction at the S-DALINAC in a momentum transfer range q = 0.3-0.6 fm^(-1). Results: Transition strengths B(E2;2+_1 -> 0+_1) = 6.18(23), B(E2; 2+_2 -> 0+_1) = 3.31(10) and B(E3; 3-_1 -> 0+_1) = 18.4(11) Weisskopf units are determined from a comparison of the experimental cross sections to quasiparticle-phonon model (QPM) calculations. It is shown that a model-independent plane wave Born approximation (PWBA) analysis can fix the ratio of B(E2) transition strengths to the 2+_(1,2) states with a precision of about 1%. The method furthermore allows to extract their proton transition radii difference. With the present data -0.12(51) fm is obtained. Conclusions: Electron scattering at low momentum transfers can provide information on transition radii differences of one-phonon 2+ states even in heavy nuclei. Proton transition radii for the 2+_(1,2) states in 92Zr are found to be identical within uncertainties. The g.s. transition probability for the mixed-symmetry state can be determined with high precision limited only by the available experimental information on the B(E2; 2+_1 -> 0+_1) value.
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