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HK: Physik der Hadronen und Kerne

HK 3: Nuclear Physics / Spectroscopy I

HK 3.4: Vortrag

Montag, 11. März 2002, 17:45–18:00, B

New methods for measuring nuclear skins — •A. Krasznahorkay^1,2, H. Akimune³, A.M. van den Berg², N. Blasi⁴, S. Brandenburg², M. Csatlós¹, H. Fujimura³, M. Fujiwara^3,5, J. Gulyás¹, M. Hagemann⁶, K. Hara³, M. N. Harakeh², M. Hunyadi², M. de Huu², F. Ihara³, T. Ishikawa⁷, Z. Máté¹, D. Sohler¹, S.Y. van der Werf², and L. Zolnai¹ — ¹ATOMKI, Debrecen, Hungary — ²KVI, Groningen, The Netherlands — ³RCNP, Osaka, Japan — ⁴INFN, Milano, Italy — ⁵JAERI, Tokai, Japan — ⁶Univ. Gent, Belgium — ⁷Univ. Kyoto, Japan

The neutron-skin thickness of ²⁰⁸Pb and ^{114, 124}Sn has been investigated in order to constrain the symmetry energy term of the nuclear energy functional. The precise knowledge of the symmetry energy is essential not only for describing the structure of neutron-rich nuclei, but also for describing the properties of the neutron-rich matter in nuclear astrophysics. We have used inelastic alpha scattering to excite the giant dipole resonance (GDR). The cross section of this process depends strongly on ΔR_np/R, the radial difference of the neutron and proton densities [1]. We have also used the excitation of the spin-dipole resonance (SDR) to measure the neutron-skin thickness since the total L=1 strength of the SDR is sensitive to it [2]. Recently new experiments were carried out at the KVI using 196 MeV α and 177 MeV ³He beams from the AGOR superconducting cyclotron. A critical test of both the GDR and SDR methods will be discussed.

[1] A. Krasznahorkay et al., Phys. Rev. Lett. 66, 1287 (1991)

[2] A. Krasznahorkay et al., Phys. Rev. Lett. 82, 3216 (1999).