Isovector soft dipole mode in Be-6

A. S. Fomichev; V. Chudoba; I. A. Egorova; S. N. Ershov; M. S. Golovkov; A. V. Gorshkov; V. A. Gorshkov; L. V. Grigorenko; G. Kaminski; S. A. Krupko; I. G. Mukha; Y. L. Parfenova; S. I. Sidorchuk; R. S. Slepnev; Ł. Standyło; S. V. Stepantsov; G. M. Ter-Akopian; R. Wolski; Mikhail Zhukov

doi:10.1016/j.physletb.2012.01.004

Isovector soft dipole mode in Be-6
Artikel i vetenskaplig tidskrift, 2012

By using the H-1(Li-6,Be-6)n charge-exchange reaction, population of continuum states in Be-6 was observed up to E-T = 16 MeV, E-T being the Be-6 energy above its three-body decay threshold. In kinematically complete measurements performed by detecting alpha + p + p coincidences, an E-T spectrum of high statistics was obtained, containing approximately similar to 5 x 10(6) events. The spectrum provides detailed correlation information about the well-known 0(+) ground state of Be-6 at E-T = 1.37 MeV and its 2(+) state at E-T = 3.05 MeV. Moreover, a broad structure extending from 4 to 16 MeV was observed. It contains negative parity states populated by Delta L = 1 angular momentum transfer without other significant contributions. This structure can be interpreted as a novel phenomenon, i.e. the isovector soft dipole mode associated with the Li-6 ground state. The population of this mode in the charge-exchange reaction is a dominant phenomenon for this reaction, being responsible for about 60% of the cross-section obtained in the measured energy range.

Kinematically complete measurements

neutron-rich nuclei

spectra

he-6

halo

light-nuclei

Be-6

Hyperspherical

excitations

isotopes

Three-body Coulomb problem

charge-exchange scattering

harmonics method

resonance

Two-proton decay

decays