Evidence of a new state in $^{11}$Be observed in the $^{11}$Li $β$-decay

M. Madurga; M. J. G. Borge; M. Alcorta; L. M. Fraile; H. O. U. Fynbo; B. Jonsond; O. Kirsebom; G. Martinez-Pinedo; T. Nilsson; G. Nyman; A. Perea; A. Poves; K. Riisager; O. Tengblad; E. Tengborn; J. Van der Walle

doi:10.1016/j.physletb.2009.05.050

arXiv · 0904.4212

Evidence of a new state in $^{11}$Be observed in the $^{11}$Li $β$-decay

M. Madurga·M. J. G. Borge·M. Alcorta·L. M. Fraile·H. O. U. Fynbo·B. Jonsond·O. Kirsebom·G. Martinez-Pinedo·T. Nilsson·G. Nyman·A. Perea·A. Poves·K. Riisager·O. Tengblad·E. Tengborn·J. Van der Walle

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Abstract

Coincidences between charged particles emitted in the $β$-decay of $^{11}$Li were observed using highly segmented detectors. The breakup channels involving three particles were studied in full kinematics allowing for the reconstruction of the excitation energy of the $^{11}$Be states participating in the decay. In particular, the contribution of a previously unobserved state at 16.3 MeV in $^{11}$Be has been identified selecting the $α$ + $^7$He$\toα$ + $^6$He+n channel. The angular correlations between the $α$ particle and the center of mass of the $^6$He+n system favors spin and parity assignment of 3/2$^-$ for this state as well as for the previously known state at 18 MeV.

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M. Madurga, M. J. G. Borge, M. Alcorta, L. M. Fraile, H. O. U. Fynbo, B. Jonsond, O. Kirsebom, G. Martinez-Pinedo, T. Nilsson, G. Nyman, A. Perea, A. Poves, K. Riisager, O. Tengblad, E. Tengborn, J. Van der Walle. 2009-04-27. Evidence of a new state in $^{11}$Be observed in the $^{11}$Li $β$-decay. https://doi.org/10.1016/j.physletb.2009.05.050

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