Near-threshold dipole strength in {^{10}}Be with isoscalar character

J. Chen; Y. Ayyad; D. Bazin; W. Mittig; M. Z. Serikow; N. Keeley; S. M. Wang; B. Zhou; J. C. Zamora; S. Beceiro-Novo; M. Cortesi; M. DeNudt; S. Heinitz; S. Giraud; P. Gueye; C. R. Hoffman; B. P. Kay; E. A. Maugeri; B. G. Monteagudo; H. Li; W. P. Liu; A. Munoz; F. Ndayisabye; J. Pereira; N. Rijal; C. Santamaria; D. Schumann; N. Watwood; G. Votta; P. Yin; C. X. Yuan; Y. N. Zhang

arXiv · 2501.05231

Near-threshold dipole strength in {^{10}}Be with isoscalar character

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Abstract

Isoscalar dipole transitions are a distinctive fingerprint of cluster structures. A {1^-} resonance at 7.27(10) MeV, located just below the {\alpha}-emission threshold, has been observed in the deuteron inelastic scattering reactions off 10Be. The deformation lengths of the excited states in 10Be below 9 MeV have been inferred from the differential cross sections using coupled channel calculations. This observed {1^-} resonance has isoscalar characteristics and exhausts approximately 5{\%}-15{\%} of the isoscalar dipole energy-weighted sum rule, providing evidence for pronounced {\alpha} cluster structure in 10Be. The Gamow coupled channel approach supports this interpretation and suggests the near-threshold effect might be playing an important role in this excitation energy domain. The {\alpha}+{\alpha}+n+n four-body calculation reproduces the observed enhanced dipole strength, implying that the four-body cluster structure is essential to describe the {1^-} states in 10Be.

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J. Chen, Y. Ayyad, D. Bazin, W. Mittig, M. Z. Serikow, N. Keeley, S. M. Wang, B. Zhou, J. C. Zamora, S. Beceiro-Novo, M. Cortesi, M. DeNudt, S. Heinitz, S. Giraud, P. Gueye, C. R. Hoffman, B. P. Kay, E. A. Maugeri, B. G. Monteagudo, H. Li, W. P. Liu, A. Munoz, F. Ndayisabye, J. Pereira, N. Rijal, C. Santamaria, D. Schumann, N. Watwood, G. Votta, P. Yin, C. X. Yuan, Y. N. Zhang. 2025-01-09. Near-threshold dipole strength in {^{10}}Be with isoscalar character. https://arxiv.org/abs/2501.05231

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