New dispersiveΛNNforce ands-shell hypernuclei

Abstract

Variational Monte Carlo calculations for the ground-and excited-state binding energies of s-shell hypernuclei using a new form of dispersive spin-dependent noncentral ⌳NN force have been made to study its effect on the overbinding problem of ⌳ 5 He and on the spin dependence of ⌳N force. A detailed analysis shows that the strength of the dispersive ⌳NN force can be adjusted to resolve the overbinding problem using two-body correlations alone. Consequently, the ambiguity in the strength of the dispersive ⌳NN force masks the effect of 2-exchange ⌳NN force and ⌳NN correlations on the data. The contribution of the dispersive force to the 0 ϩ -1 ϩ spin-flip splitting of Aϭ4 hypernuclei is not uniquely determined. Further B ⌳ data favor a small spin dependence of the ⌳N potential, a situation characteristically similar to other versions of dispersive ⌳NN potentials.

Cluster model of s- and p-shell ΛΛ hypernuclei

“…On the contrary, in our calculation it appears that dispersive force alone is sufficient to explain Be hypernuclei but this may be simulating the l-dependent potential. It may be worth recalling here that in earlier analyses [21][22][23] the role of both dispersive ΛNN and space-exchange ΛN force has been emphasized in the binding energies analyses of hypernuclei. Further spaceexchange ΛN force is equivalent to l-dependent force in the case of hypernuclei.…”

“…We have also chosen ΛΛ single channel effective potentials [9] which are constructed from Nijmegen soft-core NSC97e potential and are denoted as V e1 ΛΛ reproduces B ΛΛ of 6 ΛΛ He, V e2 ΛΛ is free-space interaction and is expected to include the cannel ΛΛ −→ ΞN , and V e ΛΛ reproduces the scattering parameters of NSC97e S = −2 interaction. Urbana-type ΛΛ potential has been successfully used in the past [4,7,12,13,[21][22][23] to analyze the S = −2 s-shell hypernuclei. Therefore, in the present analysis, the Urbana-type potential with strength V ΛΛ 0 has also been included because of its widespread use, and is of the form…”

Excited states ofΛ9BeandΛΛ10BeShoeb1 2006Phys. Rev. CSelf Cite72160View full textAdd to dashboardCite

“…The contribution of V αα to the energy is quite significant as shown in Refs. [12][13][14][15][16], neglecting it among the αα clusters overbinds the 9 Be and 10 Be. It may be noted that V (0) α , which reproduces the experimental energy of the 5 He hypernucleus, simulates the dispersive energy and other smaller effects.…”

“…Thus a modified odd state N potential appears to be crucial in explaining the data. From the analyses [3,[5][6][7]10,11], it seems that the contribution of dispersive NN forces [12,13], which theoretically have been established to be making significant contributions [14][15][16] to the energy of hypernuclei, can be ignored in the αα channel. Here it is worthwhile to remark that microscopically calculated α potentials [4,10] may not be free from the inherent uncertainties of the boson exchange models and of the prescription adopted for solving many-body problems.…”

“…In the last few years, a number of VMC calculations [2,[12][13][14][15][16] mainly for ground state of s-and p-shell hypernuclei in the few-body framework in terms of baryons degrees of freedom or of cluster model have been performed. Here we analyze the experimental binding energy B = 3.66 MeV of the degenerate doublet (3 + /2, 5 + /2) of 9 Be [17,18] and B = 12.33 +0.35 −0.21 MeV of the excited 2 + state of 10 Be [10,19] in and α cluster models using dispersive αα force in a VMC approach.…”