Spectroscopy of $A=9$ hyperlithium by the $(e,e^{\prime }{K}^{+})$ reaction

Abstract

Missing mass spectroscopy with the $(e,e^{\prime }{K}^{+})$ reaction was performed at Jefferson Laboratory's Hall C for the neutron rich $\Lambda$ hypernucleus ${}_{\Lambda }^9\mathrm{Li}$. The ground state energy was obtained to be $B_{\Lambda }^{g.s.}=8.84\pm 0.17^{stat.}\pm 0.15^{sys.}\mathrm{MeV}$ by using shell model calculations of a cross section ratio and an energy separation of the spin doublet states ($3/2_1^{+}$ and $5/2_1^{+}$). In addition, peaks that are considered to be states of [${}^8\mathrm{Li}(3^{+})\otimes s_{\Lambda }=3/2_2^{+},1/2^{+}$] and [${}^8\mathrm{Li}(1^{+})\otimes s_{\Lambda }=5/2_2^{+},7/2^{+}$] were observed at $E_{\Lambda }(no.2)=1.74\pm 0.27^{stat.}\pm 0.11^{sys.}\mathrm{MeV}$ and $E_{\Lambda }(no.3)=3.30\pm 0.24^{stat.}\pm 0.11^{sys.}\mathrm{MeV}$, respectively. The $E_{\Lambda }(no.3)$ is larger than shell model predictions by a few hundred keV, and the difference would indicate that a ${}^5\mathrm{He}+t$ structure is more developed for the $3^{+}$ state than those for the $2^{+}$ and $1^{+}$ states in a core nucleus ${}^8\mathrm{Li}$ as a cluster model calculation suggests.

5 pages, 3 figures

References in corpus (5)

• Observation of Lambda H-4 hyperhydrogen by decay-pion spectroscopy in electron scattering
• Charge symmetry breaking in $\Lambda$ hypernuclei revisited
• The experiments with the High Resolution Kaon Spectrometer at JLab Hall C and the new spectroscopy of ${}_{\Lambda }^{12}\text{B}$ hypernuclei
• Spectroscopy of Lambda-9Li by electroproduction
• Low-lying level structure of $\Lambda$ hypernuclei and spin dependence of $\Lambda N$ interaction with antisymmetrized molecular dynamics

Cited by in corpus (1)

• Fermi motion effects in electroproduction of hypernuclei