In Fig. 3 and its inset the vertical scales should be reduced by a factor of 4. This plotting error affects only the figure. All relevant quantities in the text and in the table are correct as published. We regret the oversight.The corrected version of Fig. 3 is reproduced here. This correction does not affect any results or conclusions of the published paper.FIG. 3. Inclusive ÿ ; K spectrum on Si at K 6 2 . The curves are the calculated spectra for the repulsive (solid) and shallow (dashed) -nucleus potentials, fitted to the measured spectrum. A value of the scaling factor and 2 per degree of freedom are shown for each fitting.

In order to study the Σ-nucleus optical potential, we measured inclusive (π − , K + ) spectra on medium-to-heavy nuclear targets: CH2, Si, Ni, In and Bi. The CH2 target was used to calibrate the excitation energy scale by using the elementary process p + π − → K + + Σ − , where the C spectrum was also extracted. The calibration was done with ±0.1 MeV precision. The angular distribution of the elementary cross section was measured, and agreed well with the previous bubble chamber data, but with better statistics, and the magnitudes of the cross sections of the measured inclusive (π − , K + ) spectra were also well calibrated. All of the inclusive spectra were found to be similar in shape at a region near to the Σ − binding energy threshold, showing a weak mass-number dependence on the magnitude of the cross section. The measured spectra were compared with a theoretical calculation performed within the framework of the Distorted Wave Impulse Approximation (DWIA). It has been demonstrated that a strongly repulsive Σ-nucleus potential with a non-zero size of the imaginary part is required to reproduce the shape of the measured spectra.

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.

The present status of hypernuclear γ-ray spectroscopy with Hyperball is summarized. We observed two γ transitions of 16 Λ O(1 − → 1 − , 0 − ) and obtained the strength of the ΛN tensor force. In 10 B(K − , π − γ) data, we did not observe the spin-flip M1 transition of 10 Λ B(2 − → 1 − ), but γ rays from hyperfragments such as 7 Λ Li(7/2 + → 5/2 + ) and 9 Λ Be(3/2 + → 1/2 + ) were observed. In 11 B(π + , K + γ) data, we observed six γ transitions of 11 Λ B. We also attempted an inclusive γ-ray measurement with stopped K − beam. † Present address:

We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.