Speaker
Description
We report on the kinematically complete measurement of the Coulomb breakup of the two-neutron halo nucleus $^{14}$Be on Pb at 220 MeV/nucleon at SAMURAI at RIBF. The previous study [1] showed significantly large E1 excitation of $^{14}$Be at low excitation energies, which was indicative of the revelation of the soft E1 excitation for halo nuclei, while the statistics was low and the quantitative comparison with theories was not sufficient. The current measurement has significantly higher statistics, and the gamma rays were measured in coincidence to evaluate the core-excited contribution which was missing in the previous work. We will present the energy spectrum of Coulomb breakup cross sections and E1 strength distribution dB(E1)/dEx. We apply the integrated B(E1) strength to extract the information on the dineutron correlation using the non-energy weighted E1 sum rule, which is important to assess how the spatial dineutron correlation appears. The configuration of the valence two neutrons in $^{14}$Be is considered to be a mixture of 2s-1p-1d, which may show different dineutron properties in $^{14}$Be, compared with $^{11}$Li[2,3] and $^{6}$He[4].We discuss the characteristic feature of the E1 response and dineutron correlation in $^{14}$Be.
References
[1] M. Labiche, et al., Phys. Rev. Lett. 86, 600 (2001)
[2] T. Nakamura, et al., Phys. Rev. Lett. 96, 252502 (2006).
[3] Y. Kubota et al., Phys. Rev. Lett. 125, 252501 (2020).
[4] Y.L. Sun et al., Phys. Lett. B 814, 136072 (2021).
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| Are you a student or postdoc? | yes |
