192 research outputs found

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

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    A four-body calculation of the pnΛΛpn\Lambda\Lambda bound state, $^{\ 4}_{\Lambda\Lambda}H,isperformedusingthestochasticvariationalmethodandphenomenologicalpotentials.TheH, is performed using the stochastic variational method and phenomenological potentials. The NN,, \Lambda N,and, and \Lambda\LambdapotentialsaretakenfromarecentLetterbyFilikhinandGal,PRL89,172502(2002).AlthoughtheirFaddeevYakubovskycalculationfoundnoboundstatesolutionoverawiderangeof potentials are taken from a recent Letter by Filikhin and Gal, PRL{\bf 89}, 172502 (2002). Although their Faddeev-Yakubovsky calculation found no bound-state solution over a wide range of \Lambda\Lambdainteractionstrengths,thepresentvariationalcalculationgivesaboundstateenergy,whichisclearlylowerthanthe interaction strengths, the present variational calculation gives a bound-state energy, which is clearly lower than the _\Lambda^3{H}+\Lambdathreshold,evenforaweak threshold, even for a weak \Lambda\Lambdainteractionstrengthdeducedfromarecentexperimental interaction strength deduced from a recent experimental B_{\Lambda\Lambda}(^{6}_{\Lambda\Lambda}{He})value.Thebindingenergiesobtainedarecloseto,andslightlylargerthan,thevaluesobtainedfromthethreebody value. The binding energies obtained are close to, and slightly larger than, the values obtained from the three-body d\Lambda\Lambda$ model in the Letter.Comment: Corrected typos, added addtional calculations regarding a truncated to l=0 interaction model, 4 pages, 3 figure

    Three-Cluster Equation Using Two-Cluster RGM Kernel

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    We propose a new type of three-cluster equation which uses two-cluster resonating-group-method (RGM) kernels. In this equation, the orthogonality of the total wave-function to two-cluster Pauli-forbidden states is essential to eliminate redundant components admixed in the three-cluster systems. The explicit energy-dependence inherent in the exchange RGM kernel is self-consistently determined. For bound-state problems, this equation is straightforwardly transformed to the Faddeev equation which uses a modified singularity-free T-matrix constructed from the two-cluster RGM kernel. The approximation of the present three-cluster formalism can be examined with more complete calculation using the three-cluster RGM. As a simple example, we discuss three di-neutron (3d') and 3 alpha systems in the harmonic-oscillator variational calculation. The result of the Faddeev calculation is also presented for the 3' system.Comment: 12 pages, no figur

    Three-body resonances Lambda-n-n and Lambda-Lambda-n

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    Possible bound and resonant states of the hypernuclear systems Λnn\Lambda nn and ΛΛn\Lambda\Lambda n are sought as zeros of the corresponding three-body Jost functions calculated within the framework of the hyperspherical approach with local two-body S-wave potentials describing the nnnn, Λn\Lambda n, and ΛΛ\Lambda\Lambda interactions. Very wide near-threshold resonances are found for both three-body systems. The positions of these resonances turned out to be sensitive to the choice of the Λn\Lambda n-potential. Bound Λnn\Lambda nn and ΛΛn\Lambda\Lambda n states only appear if the two-body potentials are multiplied by a factor of 1.5\sim 1.5.Comment: 12 pages, 5 figures. Acknowledgments are added in the new versio

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

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    Variational calculations for s-shell hypernuclei are performed by explicitly including Σ\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 Λ5_\Lambda^5He is obtained and a large energy expectation value of the tensor ΛNΣN\Lambda N-\Sigma N transition part is found. The internal energy of the 4^4He subsystem is strongly affected by the presence of a Λ\Lambda particle with the strong tensor ΛNΣN\Lambda N-\Sigma N transition potential.Comment: Phys. Rev. Lett. 89, 142504 (2002
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