120162764
Study of Strangeness Photoproduction on the Neutron in the Threshold Region
Photoproduction of the neutral kaon on the deuteron has been investigated at the Research Center for Electron Photon Science, Tohoku University. We constructed the Neutral Kaon Spectrometer-2 for the detection of charged particles from the decay of the neutral kaon and the hyperon. We obtained a momentum distribution of K0 with the inclusive measurement. It was consistent with the previous measurement. The total cross section of γ + d → K0 + Λ + p was estimated from the measured integral cross section of γ + d → Λ + X. The total cross section with respect to the photon energy was compared with the theoretical calculations. It favored the Saclay-Lyon A model calculation with the ratio of the neutral to charged coupling constants of the axial-vector meson, K1, as ~ −1.5. The energy dependence and the magnitude of the total cross section were similar to the total cross section of γ + p → K+ Λ.
118882013
Energy calibration of tagged photons by the d(gamma,pi-pp) reaction
124892982
Investigation of Strangeness Photoproduction near the Threshold at ELPH, Tohoku University
Masashi Kaneta1, Brian Beckford1, Petr Bydžovský2, Takeshi Fujibayashi1, Takao Fujii1, Yu Fujii1, Kenta Futatsukawa1, Toshiyuki Gogami1, Yuncheng Han3, Osamu Hashimoto1 ∗, Kentaro Hirose4, Kenji Hosomi1, Ryotarou Honda1, Aran Iguchi1, Takatsugu Ishikawa4, Hiroki Kanda1, Yusuke Kaneko1, Yuma Kasai1, Taito Kawasaki1, Chigusa Kimura1, Shogo Kiyokawa1, Takeshi Koike1, Kazushige Maeda1, Nayuta Maruyama1, Masao Matsubara1, Koji Miwa1, Yohei Miyagi1, Sho Nagao1, Satoshi N. Nakamura1, Takashi Nishizawa1, Akira Okuyama1, Miloslav Sotona2,∗, Tadaaki Tamae4, Hirokazu Tamura1, Kyo Tsukada1, Nobu Terada1, Tieshan Wang3, Fumiya Yamamoto1, Takeshi O. Yamamoto1, and Hirohito Yamazaki4 (the NKS2 collaboration)
123281050
Strangeness Nuclear Physics
Abstract Recent progress in strangeness nuclear physics is reported. The high-resolution ( e , e ′ K + ) reaction spectroscopy has been established at JLab as a new means to study Λ hypernuclear structure. Precision γ -ray spectroscopy of hypernuclei has revealed fine structure of various light Λ hypernuclei and clarified Λ N spin-dependent interactions. Production of neutron-rich Λ hypernuclei has become successful by using the ( π − , K + ) reaction at KEK. Several experimental data have implied existence of deeply-bound K ¯ -nuclear systems, and their theoretical research is also activated. Kaonic X ray measurements in light nuclei are also being carried out. The J-PARC and other facilities will allow us to accelerate these experimental studies of Λ hypernuclei and K − nuclear systems and to extend hypernuclear physics to double strangeness systems.
100878863
Study of Double Delta Photoproduction on the Deuteron in the Energy Region of Eγ = 0.65–1.1 GeV
We studied the reaction d(γ, π+π−p)n with the Neutral Kaon Spectrometer 2 (NKS2) in a photon energy region of Eγ = 0.65-1.1 GeV at Research Center for Electron Photon Science (ELPH), Tohoku University. In this reaction, existence of the process where two nucleons are excited to Delta particles in the intermediate state was found. It is suggested that the nuclear effects cannot be ignored. By exploring the double Delta photoproduction, we investigated the double pion photoproduction on the deuteron, and the N∗-N interaction which contributes to the intermediate state of this reaction. The cross section of double Delta photoproduction was measured by the TAGX[1] and the NKS[2] in the photon energy region of Eγ = 0.57-0.85 GeV and 0.8-1.1 GeV, respectively. The reported cross sections are not consisted at 0.8 GeV. The theoretical calculation[3] does not reproduce the data above 0.8 GeV. We aim to precise measure the double Delta photoproduction in the photon energy region of Eγ = 0.65-1.1 GeV. Charged particles were detected using the NKS2 which has the large acceptance. The mass of the charged particles was calculated from measurements of the β and their respective momentum, allowing for the identification of π, π− and proton events. The d(γ, π+π−p)n events were extracted with a kinematical cut on the missing momentum. Double Delta excitation in the intermediate state was shown using the invariant mass distributions for πp and π−n. In this presentation, I will report on the invariant mass distributions for πN and the cross section of the double Delta photoproduction.
121364477
Double-lambda compound nucleus and the formation of double hypernuclei
The formation probabilities of single-λ and double-λ compound nuclei from ξ− following the (K−, K+) reaction are calculated, showing that double-λ hypernuclei are formed with a fairly large probability through a hyperon compound process involving ξ− directly after the (K−, K+) reaction.
123591192
A Comment on Spontaneous Breaking of Chiral Symmetry