Full-Coupled Channel Approach to Doubly Strange ss-Shell Hypernuclei

We describe {\it ab initio} calculations of doubly strange, $S=-2$, $s$-shell hypernuclei ($^4_{\Lambda\Lambda}$H, $^5_{\Lambda\Lambda}$H, $^5_{\Lambda\Lambda}$He and $^6_{\Lambda\Lambda}$He) as a first attempt to explore the few-body problem of the {\it full}-coupled channel scheme for these systems. The wave function includes $\Lambda\Lambda$, $\Lambda\Sigma$, $N\Xi$ and $\Sigma\Sigma$ channels. Minnesota $NN$, D2$^\prime$ $YN$, and simulated $YY$ potentials based on the Nijmegen hard-core model, are used. Bound state solutions of these systems are obtained. We find that a set of phenomenological $B_8B_8$ interactions among the octet baryons in $S=0, -1$ and -2 sectors, which is consistent with all of the available experimental binding energies of $S=0, -1$ and -2 $s$-shell (hyper-)nuclei, can predict a particle stable bound state of $^4_{\Lambda\Lambda}$H. For $^5_{\Lambda\Lambda}$H and $^5_{\Lambda\Lambda}$He, $\Lambda N-\Sigma N$ and $\Xi N-\Lambda\Sigma$ potentials enhance the net $\Lambda\Lambda-N\Xi$ coupling, and a large $\Xi$ probability is obtained even for a weaker $\Lambda\Lambda-N\Xi$ potential.Comment: 4 pages, 1 figur

Ab initio approach to s-shell hypernuclei 3H_Lambda, 4H_Lambda, 4He_Lambda and 5He_Lambda with a Lambda N-Sigma N interaction

Variational calculations for s-shell hypernuclei are performed by explicitly including $\Sigma$ degrees of freedom. Four sets of YN interactions (SC97d(S), SC97e(S), SC97f(S) and SC89(S)) are used. The bound-state solution of $_\Lambda^5$He is obtained and a large energy expectation value of the tensor $\Lambda N-\Sigma N$ transition part is found. The internal energy of the $^4$He subsystem is strongly affected by the presence of a $\Lambda$ particle with the strong tensor $\Lambda N-\Sigma N$ transition potential.Comment: Phys. Rev. Lett. 89, 142504 (2002

Lambda Lambda-XiN Coupling Effects in Light Hypernuclei

The significance of $\Lambda\Lambda$-$\Xi$N coupling in double-$\Lambda$ hypernuclei has been studied. The Pauli suppression effect due to this coupling in $^6_{\Lambda\Lambda}$He has been found to be 0.43 MeV for the coupling strength of the NSC97e potential. This indicates that the free-space $\Lambda\Lambda$ interaction is stronger by about $5^{\circ}$ phase shift than that deduced from the empirical data of $^6_{\Lambda\Lambda}$He without including the Pauli suppression effect. In $^5_{\Lambda\Lambda}$He and $^5_{\Lambda\Lambda}$H, an attractive term arising from $\Lambda\Lambda$-$\Xi$N conversion is enhanced by the formation of an alpha particle in intermediate $\Xi$ states. According to this enhancement, we have found that the $\Lambda\Lambda$ binding energy ($\Delta B_{\Lambda\Lambda}$) of $^5_{\Lambda\Lambda}$He is about 0.27 MeV larger than that of $^6_{\Lambda\Lambda}$He for the NSC97e coupling strength. This finding deviates from a general picture that the heavier is the core nucleus, the larger is $\Delta B_{\Lambda\Lambda}$.Comment: 16 pages with 2 figure

Stochastic Variational Search for ΛΛ4^{4}_{\Lambda\Lambda}H

A four-body calculation of the $pn\Lambda\Lambda$ bound state, $^{\ 4}_{\Lambda\Lambda}$H, is performed using the stochastic variational method and phenomenological potentials. The$NN$,$\Lambda N$, and$\Lambda\Lambda$potentials are taken from a recent Letter by Filikhin and Gal, PRL{\bf 89}, 172502 (2002). Although their Faddeev-Yakubovsky calculation found no bound-state solution over a wide range of$\Lambda\Lambda$interaction strengths, the present variational calculation gives a bound-state energy, which is clearly lower than the$_\Lambda^3{H}+\Lambda$threshold, even for a weak$\Lambda\Lambda$interaction strength deduced from a recent experimental$B_{\Lambda\Lambda}(^{6}_{\Lambda\Lambda}{He})$value. The binding energies obtained are close to, and slightly larger than, the values obtained from the three-body$d\Lambda\Lambda$ model in the Letter.Comment: Corrected typos, added addtional calculations regarding a truncated to l=0 interaction model, 4 pages, 3 figure

New effective nuclear forces with a finite-range three-body term and their application to AMD+GCM calculations

We propose new effective inter-nucleon forces with a finite-range three-body operator. The proposed forces are suitable for describing the nuclear structure properties over a wide mass number region, including the saturation point of nuclear matter. The forces are applied to microscopic calculations of $Z=N$ ($A\le 40$) nuclei and O isotopes with a method of antisymmetrized molecular dynamics. We present the characteristics of the forces and discuss the importance of the finite-range three-body term.Comment: 15 pages, 11 figures, submitted to Phys.Rev.

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

The (K-,p) reaction on nuclei with in-flight kaons

We perform a theoretical study of the spectrum of protons with kinetic energies of around 600 MeV, emitted following the interaction of 1 GeV/c kaons with nuclei. A recent experimental analysis of this (K-,p) reaction on 12C, based on the dominant quasielastic process, has suggested a deeply attractive kaon nucleus potential. Our Monte Carlo simulation considers, in addition, the one-and two-nucleon K- absorption processes producing hyperons that decay into \pi N pairs. We find that this kaon in-flight reaction is not well suited to determine the kaon optical potential due, essentially, to the limited sensitivity of the cross section to its strength, but also to unavoidable uncertainties from the coincidence requirement applied in the experiment. A shallow kaon nucleus optical potential obtained in chiral models is perfectly compatible with the observed spectrum.Comment: To appear in the proceedings of the 10th International Conference on Hypernuclear and Strange Particle Physics, Tokai, Ibaraki (Japan), 14-18 September, 200

A search for deeply bound kaonic nuclear states

We have measured proton and neutron energy spectra by stopping negative kaons on liquid helium4. Two distinct peak structures were found on both spectra, which were assigned to the formation of new kinds of strange stribaryons. In this paper, we summarize both results.Comment: 7 pages, 3 figures, HYP2003 conference proceeding

Upper lid crease approach for margin rotation in trachomatous cicatricial entropion without external sutures

ABSTRACT Purpose: To describe the use of a lid crease incision for upper eyelid margin rotation in cicatricial entropion combining internal traction on the anterior lamella, tarsotomy, and tarsal overlap without external sutures. Methods: Surgical description: The main steps of the procedure consisted of exposure of the entire tarsal plate up to the eyelashes followed by tarsotomy through the conjunctiva. A double-armed 6.0 polyglactin suture was then passed through the distal tarsal fragment to the marginal section of the orbicularis oculi muscle. As the sutures were tied, the distal tarsus advanced over the marginal section, and traction was exerted on the marginal strip of the orbicularis muscle. There were no bolsters or external knots. The pretarsal skin-muscle flap was closed with a 6.0 plain gut suture. Results: We used this procedure at a tertiary hospital in Saudi Arabia from 2013 to 2014. Sixty upper lids of 40 patients (23 women and 17 men) were operated on, with an age range of 44-99 years [mean ± standard deviation (SD) = 70.9 ± 13.01 years]. Bilateral surgery was performed on 21 patients. Follow-up ranged from 1 to 12 months (mean 3.0 ± 2.71 months). Forty percent of the patients (24 lids) had more than 3 months' follow-up. The postoperative lid margin position was good in all cases. Trichiasis (two lashes) was observed in only one patient with unilateral entropion on the medial aspect of the operated lid. Conclusions: The upper lid margin can be effectively rotated through a lid crease incision with internal sutures. The technique combines the main mechanisms of the Wies and Trabut approaches and avoids the use of bolsters or external sutures, which require a second consultation to be removed. Some other lid problems, such as ptosis, retraction, or dermatochalasis, can be concomitantly addressed during the procedure