Experimental results from the J-PARC E13 experiments are summarized. A new experimental set up of E13 has established a platform for the future gamma-ray hypernuclear spectroscopy at J-PARC using kaon beams. New gamma rays are identified in He-4(Lambda) and F-19(Lambda). The energy of 1.406 MeV for the He-4(Lambda)(1(+)-> 0(+)) transition confirmed a sizable effect of Charge Symmetry Breaking (CSB) in Lambda N interaction in the A=4 hypernuclear system. The identification of four gamma rays in F-19(Lambda) is made for the first time in sd shell hypernuclei. Especially, energy spacing of the ground state doublet is found to be 315.5 keV. A good agreement with two theoretical calculations suggests that the theoretical formalism used in p shell hypernuclei is also applicable to heavier hypernuclei. Lastly, an overview of the future J-PARC E63 experiment is given.

We searched for the bound state of the neutron-rich Lambda-hypernucleus H-6(Lambda), using the Li-6(pi(-), K+)X double charge-exchange reaction at a pi-beam momentum of 1.2 GeV/c at J-PARC. A total of 1.4 x 10(12) pi(-) was driven onto a Li-6 target of 3.5-g/cm(2) thickness. No event was observed below the bound threshold, i.e., the mass of H-4(Lambda) + 2n, in the missing-mass spectrum of the Li-6(pi(-), K+) X reaction in the 2 degrees < theta(pi K) < 20 degrees angular range. Furthermore, no event was found up to 2.8 MeV/c(2) above the bound threshold. We obtained the double-differential cross section spectra of the Li-6(pi(-), K+)X reaction in the angular range of 2 degrees < theta(pi K) < 14 degrees. An upper limit of 0.56 nb/sr (90% C.L.) was obtained for the production cross section of the H-6(Lambda) hypernucleus bound state. In addition, not only the bound state region, but also the Lambda continuum region and part of the Sigma(-) quasifree production region of the Li-6(pi(-), K+) reaction were obtained with high statistics. The present missing-mass spectrum will facilitate the investigation of the Sigma(-) -nucleus optical potential for Sigma(-) -He-5 through spectrum shape analysis.

A hypernulear γ-ray spectroscopy experiment (E13) will be performed using K -beam at the K1.8 beam line of the J-PARC Hadron Experimental Facility in 2015.In this experiment, we will determine the B(M 1) value of the Λ spin-flip transition of the ground state doublet in 19 Λ F to investigate the magnetic moment of a Λ hyperon in nuclei.In order to check the performance of the whole spectrometer system of E13, a commissioning run was performed at the K1.8 beam line in 2013.We confirmed that the E13 setup is almost ready for the next beam time in 2015.In particular, new detectors for suppressing events from the two main K -decay modes in the on-line and off-line analyses are installed.As a result, the signal to noise ratio of gamma spectra is drastically improved, and the sensitivity to the B(M 1) measurement is expected to increase.

T. O. Yamamoto, M. Agnello, 3 Y. Akazawa, N. Amano, K. Aoki, E. Botta, 6 N. Chiga, H. Ekawa, P. Evtoukhovitch, A. Feliciello, M. Fujita, T. Gogami, S. Hasegawa, S. H. Hayakawa, T. Hayakawa, R. Honda, K. Hosomi, S .H. Hwang, N. Ichige, Y. Ichikawa, M. Ikeda, K. Imai, S. Ishimoto, S. Kanatsuki, M. H. Kim, S. H. Kim, S. Kinbara, T. Koike, J .Y. Lee, S. Marcello, 6 K. Miwa, T. Moon, T. Nagae, S. Nagao, Y. Nakada, M. Nakagawa, Y. Ogura, A. Sakaguchi, H. Sako, Y. Sasaki, S. Sato, T. Shiozaki, K. Shirotori, H. Sugimura, S. Suto, S. Suzuki, T. Takahashi, H. Tamura, K. Tanabe, K. Tanida, Z. Tsamalaidze, M. Ukai, Y. Yamamoto, and S. B. Yang (J-PARC E13-1 Collaboration) Department of Physics, Tohoku University, Sendai 980-8578, Japan Dipartimento di Scienza Applicate e Tecnologica, Politecnico di Torino, Corso Duca degli Abruzzi, 10129 Torino, Italy INFN, Sezione di Torino, via P. Giuria 1, 10125 Torino, Italy Department of Physics, Kyoto University, Kyoto 606-8502, Japan Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Tsukuba, 305-0801, Japan Dipartimento di Fisica, Universit di Torino, Via P. Giuria 1, 10125 Torino, Italy Department of Physics, Kyoto University, Kyoto 606-8502, Japan Joint Institute for Nuclear Research, Dubna ,Moscow Region 141980, Russia Advanced Science Research Center (ASRC), Japan Atomic Agency (JAEA), Tokai, Ibaraki 319-1195, Japan Department of Physics, Osaka University, Toyonaka 560-0043, Japan Departiment of Physics, Korea University, Seoul 136-713, Korea Faculty of Education, Gifu University, Gifu 501-1193, Japan Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea Research Center of Nuclear Physics, Osaka University, Ibaraki 567-0047, Japan (Dated: August 4, 2015)

The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2  keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

We have carried out an experiment to search for a neutron-rich hypernucleus, $^6_{\Lambda}$H, by the $^6$Li($\pi^-,K^+$) reaction at $p_{\pi^-}$ =1.2 GeV/$c$. The obtained missing mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the $^6_{\Lambda}$H hypernucleus neither below nor above the $^4_{\Lambda}$H$+2n$ particle decay threshold. An upper limit of the production cross section for the bound $^6_{\Lambda}$H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.

We carried out an experiment to produce the neutron-rich hypernucleus Λ6H via the (π−, K+) reaction on 6Li target at the pion beam momentum of 1.2 GeV/c (J-PARC E10). In order to calibrate the scale of the missing-mass or of the Λ binding energy of the hypernucleus, we also measured the 12C(π+, K+) Λ12C, p(π−, K+)Σ− and p(π+, K+)Σ+reactions. The experiment was performed at the J-PARC Hadron Hall K1.8 beam line in December 2012 and January 2013. The overall collected data sample corresponds to an integrated beam intensity of 1.65 × 1012 pions.

We have carried out an experiment to search for a neutron-rich hypernucleus, by the 6(Lambda)H by the 6Li(pi(-), K+) reaction at p(pi)- = 1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the 6(Lambda)H hypernucleus neither below nor above the 4(Lambda)H+2n particle decay threshold. An upper limit of th production cross section for the bound 6(Lambda)H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level. (c) 2014 The Authors. Published by Elsevier B.V. All rights reserved.