I. Poltoratska
Technische Universität Darmstadt
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Featured researches published by I. Poltoratska.
Physical Review Letters | 2011
A. Tamii; I. Poltoratska; P. von Neumann-Cosel; Y. Fujita; T. Adachi; C. A. Bertulani; J. Carter; M. Dozono; H. Fujita; K. Fujita; K. Hatanaka; D. Ishikawa; Masatoshi Itoh; T. Kawabata; Y. Kalmykov; A. M. Krumbholz; Elena Litvinova; H. Matsubara; K. Nakanishi; R. Neveling; H. Okamura; H. J. Ong; Banu Ozel-Tashenov; V. Yu. Ponomarev; A. Richter; B. Rubio; Harutaka Sakaguchi; Y. Sakemi; Y. Sasamoto; Y. Shimbara
A benchmark experiment on (208)Pb shows that polarized proton inelastic scattering at very forward angles including 0° is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted E1 polarizability leads to a neutron skin thickness r(skin) = 0.156(-0.021)(+0.025) fm in (208)Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars.
Physical Review C | 2012
I. Poltoratska; P. von Neumann-Cosel; A. Tamii; T. Adachi; C. A. Bertulani; J. Carter; M. Dozono; H. Fujita; K. Fujita; Y. Fujita; K. Hatanaka; Masatoshi Itoh; T. Kawabata; Y. Kalmykov; A. M. Krumbholz; E. Litvinova; H. Matsubara; K. Nakanishi; R. Neveling; H. Okamura; H. J. Ong; B. Oezel-Tashenov; V. Yu. Ponomarev; A. Richter; B. Rubio; Harutaka Sakaguchi; Y. Sakemi; Y. Sasamoto; Y. Shimbara; Y. Shimizu
Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208 Pb shows that, at very forward angles, J π = 1 − states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV; that is, in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the electromagnetic transition strength and the energy centroid of the PDR.
Physical Review C | 2015
T. Hashimoto; A. M. Krumbholz; P.-G. Reinhard; A. Tamii; P. von Neumann-Cosel; T. Adachi; N. Aoi; C. A. Bertulani; H. Fujita; Y. Fujita; E. Ganioǧlu; K. Hatanaka; E. Ideguchi; C. Iwamoto; T. Kawabata; N. T. Khai; A. Krugmann; D. Martin; H. Matsubara; K. Miki; R. Neveling; H. Okamura; H. J. Ong; I. Poltoratska; V. Yu. Ponomarev; A. Richter; H. Sakaguchi; Y. Shimbara; Y. Shimizu; J. Simonis
The electric dipole strength distribution in 120Sn between 5 and 22 MeV has been determined at RCNP Osaka from a polarization transfer analysis of proton inelastic scattering at E_0 = 295 MeV and forward angles including 0{\deg}. Combined with photoabsorption data an electric dipole polarizability \alpha_D(120Sn) = 8.93(36) fm^3 is extracted. The dipole polarizability as isovector observable par excellence carries direct information on the nuclear symmetry energy and its density dependence. The correlation of the new value with the well established \alpha_D(208Pb) serves as a test of its prediction by nuclear energy density functionals (EDFs). Models based on modern Skyrme interactions describe the data fairly well while most calculations based on relativistic Hamiltonians cannot.
Physics Letters B | 2015
A. M. Krumbholz; P. von Neumann-Cosel; T. Hashimoto; A. Tamii; T. Adachi; C.A. A Bertulani; H. Fujita; Y. Fujita; E. Ganioglu; K. Hatanaka; C. Iwamoto; T. Kawabata; N. T. Khai; A. Krugmann; D. Martin; H. Matsubara; R. Neveling; H. Okamura; H. J. Ong; I. Poltoratska; V. Yu. Ponomarev; A. Richter; H. Sakaguchi; Y. Shimbara; Y. Shimizu; J. Simonis; F. D. Smit; G. Susoy; J. H. Thies; T. Suzuki
Electric dipole strength in 120 Sn below the neutron threshold has been extracted from proton inelastic scattering experiments at Ep = 295 MeV and at forward angles including 0 . The strength distribution is very dierent from the results of a 120 Sn(; 0 ) experiment and peaks at an excitation energy of 8.3 MeV. The total strength corresponds to 2.3(2)% of the energy-weighted sum rule and is more than three times larger than what is observed with the (; 0 ) reaction. This implies a strong fragmentation of the E1 strength and/or small ground state branching ratios of the excited 1 states.
European Physical Journal A | 2014
A. Tamii; P. von Neumann-Cosel; I. Poltoratska
Abstract.The electric dipole (E1 response of 208Pb has been precisely determined by measuring Coulomb excitation induced by proton scattering at very forward angles. The electric dipole polarizability, defined as inverse energy-weighted sum rule of the E1 strength, has been extracted as
Physical Review C | 2013
A. Obeid; O. Burda; M. Chernykh; A. Krugmann; P. von Neumann-Cosel; N. Pietralla; I. Poltoratska; V. Yu. Ponomarev; C. Walz
\alpha_{D}=20.1\pm 0.6
Journal of Physics: Conference Series | 2011
R. Neveling; H. Fujita; F. D. Smit; T. Adachi; G.P.A. Berg; E.Z. Buthelezi; J. Carter; J.L. Conradie; M. Couder; R. Fearick; S. V. Förtsch; D.T. Fourie; Y. Fujita; J. Görres; K. Hatanaka; Anna Maria Heilmann; J. P. Mira; S.H.T. Murray; P. von Neumann-Cosel; S. O'Brien; P. Papka; I. Poltoratska; A. Richter; E. Sideras-Haddad; J. A. Swartz; A. Tamii; I. Usman; J. J. van Zyl
fm3. The data can be used to constrain the neutron skin thickness of 208Pb to
J.Phys.Conf.Ser. | 2011
Anna Maria Heilmann; Yuki Fujita; A. Krugmann; H. Okamura; F. D. Smit; T. Kawabata; J. Zenihiro; C. A. Bertulani; Y. Sasamoto; Hoi Jin Ong; Masaru Yosoi; Banu Ozel-Tashenov; H. Fujita; Yohei Shimizu; John Carter; A. Richter; Tatsuya Adachi; T. Suzuki; Y. Shimbara; Peter von Neumann-Cosel; K. Hatanaka; Harutaka Sakaguchi; Y. Tameshige; Yusuke Yasuda; A. Tamii; V. Ponomarev; Y. Sakemi; Elena Litvinova; I. Poltoratska; H. Matsubara
\Delta r_{np}=0.165\pm (0.009)_{expt}\pm (0.013)_{theor} \pm (0.021)_{est}
Journal of Physics: Conference Series | 2010
Abdulrahman Scheikh Obeid; O. Burda; M. Chernykh; A. Krugmann; P. von Neumann-Cosel; N. Pietralla; I. Poltoratska; V. Ponomarev; C. Walz
fm, where the subscript “expt” refers to the experimental uncertainty, “theor” to the theoretical confidence band and “est” to the uncertainty associated with the estimation of the symmetry energy at the saturation density. In addition, a constraint band has been extracted in the plane of the symmetry energy (J and its slope parameter (L at the saturation density.
CAPTURE GAMMA‐RAY SPECTROSCOPY AND RELATED TOPICS: Proceedings of the 13th#N#International Symposium on Capture Gamma‐Ray Spectroscopy and Related Topics | 2009
P. von Neumann-Cosel; T. Adachi; C. A. Bertulani; J. Carter; M. Dozono; Hisanori Fujita; K. Fujita; Y. Fujita; H. Hashimoto; K. Hatanaka; Masatoshi Itoh; Y. Kalmykov; K. Kato; T. Kawabata; H. Matsubara; K. Nakanishi; R. Neveling; H. Okamura; I. Poltoratska; V. Yu. Ponomarev; A. Richter; B. Rubio; H. Sakaguchi; Y. Sakemi; Y. Sasamoto; Y. Shimbara; Y. Shimizu; F. D. Smit; Y. Tameshige; A. Tamii
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 92 Zr, a difference could be experimentally established for the neutron components, while about equal proton transition radii were indicated by the data. Purpose: Determination of the ground-state (g.s.) transition strength of the mixed-symmetry 2 + state and verification of the expected vanishing of the proton transition radii difference between the one-phonon 2 + states in 92 Zr. Method:Differential cross sections for the excitation of one-phonon 2 + and 3 − states in 92 Zr have been measured with the (e, e � ) reaction at the S-DALINAC in a momentum transfer range q � 0.3‐0. 6f m −1 . Results: Transition strengths B(E2;2 + → 0 + ) = 6.18(23), B(E2;2 + → 0 + ) = 3.31(10), and B(E3;3 − → 0 + ) = 18.4(1.1) 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 +,2 states with a precision of about 1%. The method furthermore allows to extract their proton transition radii difference. With the present /