Hyperspherical harmonics calculations for hypernucleus 3H and double hypernucleus 6He

The hyperspherical harmonics method is used to determine the binding energy Bsub(#betta#) for sub(#betta#)sup(3)H and the #betta# #betta#-separation energy for the double hypernucleus sub(#betta# #betta#)sup(6)H. The ground state energy of sub(#betta#)sup(3)H is calculated by retaining fifteen harmonics, and using #betta#-N and N-N potentials of the Volkov type fitted to the Nagel's meson theoretic values of the scattering lengths and effective ranges. The #betta#-binding (B) gets reduced from 0.33 MeV to 0.13 MeV by the addition of a repulsive core. Retaining only nine harmonics, a convergent result is obtained for #betta# #betta#-separation energy in sub(#betta# #betta#)sup(6)He, using Tang and Herdon's α-#betta# potential and a two term #betta# - #betta# potential of the Volkov type. The experimental Bsub(#betta##betta#) value of 10.8 MeV can be reproduced with a #betta# - #betta# potential that gives rise to the scattering length of -2.23 fm. and an effective range of 3.31 fm. (author)