57,720 research outputs found

    Momentum distribution and correlation of two-nucleon relative motion in 6^6He and 6^6Li

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    The momentum distribution of relative motion between two nucleons gives information on the correlation in nuclei. The momentum distribution is calculated for both 6^{6}He and 6^6Li which are described in a three-body model of α\alpha+NN+NN. The ground state solution for the three-body Hamiltonian is obtained accurately using correlated basis functions. The momentum distribution depends on the potential model for the NN-NN interaction. With use of a realistic potential, the 6^6He momentum distribution exhibits a dip around 2 fm1^{-1} characteristic of SS-wave motion. In contrast to this, the 6^6Li momentum distribution is very similar to that of the deuteron; no dip appears because it is filled with the DD-wave component arising from the tensor force.Comment: 14 pages, 9 figure

    Low Energy Solar Neutrino Detection by using Liquid Xenon

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    Possibility to use ultra pure liquid Xenon as a low energy solar neutrino detector by means of ν\nu+e scatterings is evaluated. A possible detector with 10 tons of fiducial volume will give \sim14 events for pp-neutrinos and \sim6 events for 7^{7}Be neutrinos with the energy threshold at 50 keV. The detector can be built with known and established technologies. High density of the liquid- Xe would provide self-shields against the incoming backgrounds originating from the container and outer environments. Internal backgrounds can be reduced by distillation and other techniques. Purification of the liquid Xe can be done continuously throughout the experiment. The spallation backgrounds are estimated to be small though an experimental determination is neccessary. The liquid-Xe detector can also provide a significantly better sensitivity for the double beta decay and a dark matter search. However the 2ν\nu double beta decay of 136^{136}Xe would be most background. It could be overcome if the 2ν\nu lifetime is longer than 1022^{22}yr. However, an isotope separation of 136^{136}Xe is inevitable for a shorter lifetime. The isotope separations would, intoroduce a new opportunity to definitively identify dark matter. The interesting feature in addition to the solar neutrino measurements will also be discussed.Comment: 16 pages, 4 figures, Talk presented at LowNu workshop, June-15-2000, Sudbury, Canad

    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

    Correlated-Gaussian approach to linear-chain states -Case of four α\alpha-particles-

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    We show that correlated Gaussians with good angular momentum and parity provide flexible basis functions for specific elongated shape. As its application we study linear-chain states of four-alpha particles in variation-after-projection calculations in which all the matrix elements are evaluated analytically. We find possible chain states for J=0+J=0^+, 2+2^+, 4+4^+ and perhaps 6+6^+ with the bandhead energy being about 33 MeV from the ground state of 16^{16}O. No chain states with J8J\geq 8 are found. The nature of the rotational sequence of the chain states is clarified in contrast to a rigid-body rotation. The quadrupole deformation parameters estimated from the chain states increase from 0.59 to 1.07 for 2+2^+ to 6+6^+. This work suggests undeveloped fields for the correlated Gaussians beyond those problems which have hitherto been solved successfully.Comment: 13 pages, 6 figures, accepted for publication in Phys. Rev.
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