Exchange Currents for Hypernuclear Magnetic Moments

The meson(K and $\pi$) exchange currents for the hypernuclear magnetic moments are calculated using the effective Lagrangian method. The seagull diagram, the mesonic diagram and the $\Sigma^0$-excitation diagram are considered. The $\Lambda$-N exchange magnetic moments for the ${}^5_{\Lambda}He$, ${}^6_{\Lambda}He$ and ${}^6_{\Lambda}Li$ are calculated employing the harmonic oscillator shell model. It is found that the two-body correction is about -9% of the single particle value for ${}^5_{\Lambda}He$. The $\pi$ exchange current, induced only in the $\Sigma^0$-excitation diagram, is found to give dominant contribution for the isovector magnetic moments of hypernuclei with A=6.Comment: 11pp, LaTeX, 7 EPS figures, uses epsf.st

Spin observables in the pn→pΛpn \to p \Lambda reaction

The T matrix of the LambdaN-> NN reaction, which is a strangeness changing weak process, is derived. The explicit formulas of the spin observables are given for s-wave p-Lambda final states which kinematically corresponds to inverse reaction of the weak nonmesonic decay of Lambda hypernuclei. One can study interferences between amplitudes of parity- conserving and violating, spin- singlet and triplet and isospin- singlet and triplet. Most of them are not available in the study of the nonmesonic decay. They clarify structure of the reaction and constrain strongly theoretical models for weak hyperon nucleon interaction.Comment: 7pages,ReVTeX,no figure

Proton asymmetry in non-mesonic weak decay of light hypernuclei

We have obtained the decay asymmetry parameters in non-mesonic weak decay of polarized Lambda-hypernuclei by measuring the proton asymmetry. The polarized Lambda-hypernuclei, 5_Lambda-He, 12_Lambda-C, and 11_Lambda-B, were produced in high statistics via the (pi^+,k^+) reaction at 1.05 GeV/c in the forward angles. Preliminary analysis shows that the decay asymmetry parameters are very small for these s-shell and p-shell hypernuclei.Comment: 4pages, 4figures, International Conference on Hypernuclear and Strange Particle Physics (HYP2003

Plans for Hadronic Structure Studies at J-PARC

Hadron-physics projects at J-PARC are explained. The J-PARC is the most-intense hadron-beam facility in the multi-GeV high-energy region. By using secondary beams of kaons, pions, and others as well as the primary-beam proton, various hadron projects are planned. First, some of approved experiments are introduced on strangeness hadron physics and hadron-mass modifications in nuclear medium. Second, future possibilities are discussed on hadron-structure physics, including structure functions of hadrons, spin physics, and high-energy hadron reactions in nuclear medium. The second part is discussed in more details because this is an article in the hadron-structure session.Comment: 10 pages, LaTeX, 20 eps files, to be published in Journal of Physics: Conference Series (JPCS), Proceedings of the 24th International Nuclear Physics Conference (INPC 2010), Vancouver, Canada, July 4 - 9, 201

Final State Interactions in Hypernuclear Decay

We present an update of the One-Meson-Exchange (OME) results for the weak decay of s- and p-shell hypernuclei (Ref. Phys. Rev. C {\bf 56}, 339 (1997)), paying special attention to the role played by final state interactions between the emitted nucleons. The present study also corrects for a mistake in the inclusion of the $K$ and $K^*$ exchange mechanisms, which substantially increases the ratio of neutron-induced to proton-induced transitions, $\Gamma_n/\Gamma_p$. With the most up-to-date model ingredients, we find that the OME approach is able to describe very satisfactorily most of the measured observables, including the ratio $\Gamma_n/\Gamma_p$.Comment: 20 pages, 2 eps figure

The HypHI project: Hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and FAIR

The HypHI collaboration aims to perform a precise hypernuclear spectroscopy with stable heavy ion beams and rare isotope beams at GSI and fAIR in order to study hypernuclei at extreme isospin, especially neutron rich hypernuclei to look insight hyperon-nucleon interactions in the neutron rich medium, and hypernuclear magnetic moments to investigate baryon properties in the nuclei. We are currently preparing for the first experiment with $^6$Li and $^{12}$C beams at 2 AGeV to demonstrate the feasibility of a precise hypernuclear spectroscopy by identifying $^{3}_{\Lambda}$H, $^{4}_{\Lambda}$H and $^{5}_{\Lambda}$He. The first physics experiment on these hypernuclei is planned for 2009. In the present document, an overview of the HypHI project and the details of this first experiment will be discussed.Comment: 5 pages, 2 figures, French-Japanese symposium 2008, Paris (France