Spectroscopic study ofBΛ10,CΛ12,SiΛ28,YΛ89,LaΛ139, andPbΛ208by the (π+,K+) reaction

Hypernuclear mass spectra of ${\mathrm{}}_{\mathrm{\Lambda }}^{10}$B, ${\mathrm{}}_{\mathrm{\Lambda }}^{12}$C, ${\mathrm{}}_{\mathrm{\Lambda }}^{28}$Si, ${\mathrm{}}_{\mathrm{\Lambda }}^{89}$Y, ${\mathrm{}}_{\mathrm{\Lambda }}^{139}$La, and ${\mathrm{}}_{\mathrm{\Lambda }}^{208}$Pb were measured by the (${\mathrm{\pi }}^{+}$,${\mathit{K}}^{+}$) reaction with an energy resolution of 2 MeV (FWHM). The experiment was carried out with a 1.06 GeV/c ${\mathrm{\pi }}^{+}$ beam from the KEK 12-GeV PS and with the superconducting kaon spectrometer (SKS). For light hypernuclei, core-excited states were resolved for the first time. For heavy hypernuclei, peak structure reflecting Λ shell structure was observed. © 1996 The American Physical Society.