Frankfurt 2014 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 46: Poster
HK 46.20: Poster
Donnerstag, 20. März 2014, 16:00–18:00, HZ Poster
Study of Dipole Responses in 120Sn by (p,p’) Measurement at zero-degrees — •Anna Maria Krumbholz1, Peter von Neumann-Cosel1, Atsushi Tamii2, and Vladimir Yu. Ponomarev1 for the E316 collaboration — 1TU Darmstadt — 2RCNP, Osaka
A consistent and powerful method to measure electric and magnetic dipole modes over a broad excitation energy range including energies below and above the neutron separation energy is polarized proton scattering at small scattering angles including 0∘ [1]. A topic of high current
interest is the question whether (γ,γ’) data provide the correct strength of the pygmy dipole resonance (PDR) since the extraction of B(E1) strength depends on the unobserved branching ratios to excited states. Furthermore, parts of the strength may be missed because of the limits of energy resolution and detection sensitivity. Spectroscopy of the PDR provides important insight into a possible interpretation of the mode as a neutron skin oscillation.
Measurements of 120Sn(p,p’) reaction have been performed at RCNP with a beam energy of 295 MeV and an energy resolution of about 25 keV. For the separation of electric and magnetic contributions two different independent methods are applied, viz. a multipole decomposition of the angular distributions of the cross sections based on DWBA calculations and a model-independent analysis based on polarization transfer coefficients.
Results of the analysis will be presented and compared to a 120Sn(γ, γ’) experiment [2].
A. Tamii et al., Phys. Rev. Lett. 107, 062502 (2011).
B. Özel, Ph.D. thesis, Çukurova University, Adana, Turkey (2008).
*Supported by DFG under contracts SFB 634 and NE 679/3-1.