High Resolution Spectroscopic Study of $^{10}_Λ$Be

Abstract

Spectroscopy of a 10Λ Be hypernucleus was carried out at JLab Hall C using the (e, e ′ K + ) reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, was used to obtain an energy spectrum with a resolution of ∼ 0.78 MeV (FWHM). The well-calibrated spectrometer system of the present experiment using p(e, e ′ K + )Λ,Σ 0 reactions allowed us to determine the energy levels, and the binding energy of the ground state peak (mixture of 1 − and 2 − states) was obtained to be BΛ = 8.55 ± 0.07(stat.) ± 0.11(sys.) MeV. The result indicates that the ground state energy is shallower than that of an emulsion study by about 0.5 MeV which provides valuable experimental information on the charge symmetry breaking effect in the ΛN interaction.

First observation of a nuclear $s$-state of $Ξ$ hypernucleus, $^{15}_Ξ{\rm C}$

“…to calculate the rest mass was obtained with reference to [4,[43][44][45][46][47][48][49][50]. The B Λ of possible single Λ hypernuclei, not yet measured experimentally, were obtained by linear approximation from known B Λ with the same atomic number.…”

“…The B Λ values of 5 Λ He and 9 Λ Be were measured to be 3.12 ± 0.02 MeV and 6.71 ± 0.04 MeV, respectively using the nuclear emulsion [43]. The B Λ of 10 Λ Be was measured to be 8.55 ± 0.13 MeV using the missing mass spectroscopy [50]. The excitation energy of 9 Λ Be is an average of γ-ray energies of two E2 transitions (5/2 + →1/2 + and 3/2 + →1/2 + ) [53].…”

“…The excitation energy of 9 Λ Be is an average of γ-ray energies of two E2 transitions (5/2 + →1/2 + and 3/2 + →1/2 + ) [53]. The excitation energy of 10 Λ Be is the first separable gap of B Λ values, because the first excited state and the ground state are a doublet with energy spacing of ∼0.1 MeV [50].…”

Leading order relativistic hyperon-nucleon interactions in chiral effective field theory

“…( 19) for V Y Y ′ CT ( 3 P 0 ) is only valid for N N interactions, because the structures of the Lagrangians for 1 S 0 and 3 S 1 partial waves are different in ΛN −ΣN systems, as shown in Eqs. (7)(8)(9)(10)(11)(12)(13)(14). To recover the potentials in the HB approach we simply take R p = R p ′ = 0 and ξ B = 1.…”

“…In recent years, open questions such as charge symmetry breaking in A = 4 Λ-hypernuclei [4] and the existence of the H-dibaryon [5] have attracted a lot of attention [6][7][8][9][10][11]. In facilities like JLab, J-PARC, KEK, MAMI, and COSY, many important studies are being pursued, e.g., the level spectra and decay properties of Λ, double Λ and Ξ hypernuclei [12][13][14][15][16], Σp scattering [17], and final state interactions in production reactions, such as pp → K + Λp [18], which can provide information on the ΛN scattering lengths. Meanwhile, theoretical few-and many-body calculations of hypernuclei have made steady progress, see, e.g., Refs.…”