Core nucleus polarization in lambda (۸) hypernuclei
The response of the core nucleus to the L in a hypernucleus is studied with a local density approximation. This reproduces the energies and radii of the core nuclei as well as the L-single particle (s.p.) energies quite well. The polarizing effect of the L depends on the core response through an...
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| Format: | Thesis |
| Language: | English |
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| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31921/1/Page%201-24.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/31921/2/Full%20text.pdf |
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| Summary: | The response of the core nucleus to the L in a hypernucleus is studied with a local
density approximation. This reproduces the energies and radii of the core nuclei as
well as the L-single particle (s.p.) energies quite well. The polarizing effect of the L
depends on the core response through an “effective” compression modulus KA of the
nucleus. For certain class of energy functional, KA is found to be almost independent
of the compression modulus K of the infinite nuclear matter. This indeed is a
surprising result, and at variance with the Hartree-Fock calculations with effective
interactions. Reasons for this discrepancy were carefully examined, by considering
values of K in the range 100-400 MeV. Furthermore, the polarizing effects also
depend critically on D(r), the L binding in nuclear matter at density r. For only a
direct LN force: D µr and the core nucleus contracts giving rise to a relatively larger
core polarization. However, for a “saturating” D(r) (with a maximum at rm < r0,
where r0 is the nuclear matter equilibrium density), which is required to fit the s.p.
data, the s-Shell hypernuclei binding energies and the low energy Lp scattering data,
and which results from a LN force (including exchange) and LNN forces, there may
be an expansion of the nucleus with nucleons flowing from the interior to the surface.
This is shown to reduce the core polarization effects substantially (for rm in the
neighborhood of r0). The resulting changes in root mean square radius and core
energy depend on A, but are mostly very small, justifying their general neglect. The
present work thus demonstrates that L can be used as a reliable tool to probe the
properties of nuclei. |
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