A. Matsumura

γ-ray spectroscopy in Λ hypernuclei

Abstract 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 a stopped K − beam.

Photoproduction of neutral kaons on a liquid deuterium target in the threshold region

The photoproduction process of neutral kaons on a liquid deuterium target is investigated near the threshold region, E{sub {gamma}}=0.8-1.1 GeV. K{sup 0} events are reconstructed from positive and negative pions, and differential cross sections are derived. Experimental momentum spectra are compared with those calculated in the spectator model using a realistic deuteron wave function. Elementary amplitudes as given by recent isobar models and a simple phenomenological model are used to study the effect of the new data on the angular behavior of the elementary cross section. The data favor a backward-peaked angular distribution of the elementary n({gamma},K{sup 0}){lambda} process, which provides additional constraints on current models of kaon photoproduction. The present study demonstrates that the n({gamma},K{sup 0}){lambda} reaction can provide key information on the mechanism of the photoproduction of strangeness.

Photo-production of neutral kaons on 12C in the threshold region

Abstract The kaon photo-production process on 12C has been studied by measuring neutral kaons in the photon energy range of 0.8–1.1 GeV. Neutral kaons were identified by the invariant mass constructed from two charged pions emitted in the K S 0 → π + π − decay channel. The differential and integrated cross sections in the threshold photon energy region were obtained. The obtained momentum spectra were compared with a Spectator model calculation using elementary amplitudes of kaon photo-production given by recent isobar models. The present results provide the first information on the n ( γ , K 0 ) Λ reaction, which is expected to play an important role in constructing models of strangeness production by electromagnetic interactions. The experimental results show that the cross section of C 12 ( γ , K 0 ) is of the same order as that of C 12 ( γ , K + ) and suggest that a slightly backward K 0 angular distribution is favored in the γ n → K 0 Λ process.

High resolution spectroscopic study of Be Λ10

Spectroscopy of a

Separated response function ratios in exclusive, forward π(±) electroproduction.

^{10}_{\Lambda}

Energy calibration of tagged photons by the d(γ,π−pp) reaction

Be hypernucleus was carried out at JLab Hall C using the

High resolution spectroscopic study of

(e,e^{\prime}K^{+})

^{10}_{\Lambda}

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 the

Be

p(e,e^{\prime}K^{+})\Lambda,\Sigma^{0}

Kaon, pion, and proton associated photofission of Bi nuclei

reactions allowed us to determine the energy levels, and the binding energy of the ground state peak (mixture of 1