1,534 research outputs found
Lambda hyperonic effect on the normal driplines
A generalized mass formula is used to calculate the neutron and proton drip
lines of normal and lambda hypernuclei treating non-strange and strange nuclei
on the same footing. Calculations suggest existence of several bound
hypernuclei whose normal cores are unbound. Addition of Lambda or,
Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the
neutron and proton driplines from their conventional limits.Comment: 6 pages, 4 tables, 0 figur
Isobaric incompressibility of the isospin asymmetric nuclear matter
The isospin dependence of the saturation properties of asymmetric nuclear
matter, particularly the incompressibility at saturation density is systematically studied using density
dependent M3Y interaction. The characterizes the isospin dependence of
the incompressibility at saturation density . The approximate
expression is often used for where
and represent, respectively, the slope and curvature parameters of
the symmetry energy at . It can be expressed accurately as
where is the third-order
derivative parameter of symmetric nuclear matter at . The results of
this addendum to Phys. Rev. C 80, 011305(R) (2009) indicate that the
contribution to is not insignificant.Comment: 4 pages including 1 table and 1 figur
A Mass Formula from Light to Hypernuclei
Simultaneous description of ordinary and hypernuclei masses by a single mass
formula has been a great challenge in nuclear physics. Hyperon-separation
energies of about forty Lambda(), three
Lambda-Lambda(), one Sigma() and seven Cascade()
hypernuclei have been experimentally found. Many of these nuclei are of light
masses. We prescribe a new mass formula, called BWMH, which describes the
normal and hypernuclei on the same footing. It is based on the
modified-Bethe-Weizs\"acker mass formula (BWM). BWM is basically an extension
of the Bethe-Weizs\"acker mass formula (BW) for light nuclei. The parameters of
BWM were optimized by fitting about 3000 normal nuclei available recently. The
original Bethe-Weizs\"acker mass formula (BW) was designed for medium and heavy
mass nuclei and it fails for light nuclei. Two earlier works on hypernuclei
based on this BW show some limitations. The BWMH gives improved agreement with
the experimental data for the line of stability, one-neutron separation energy
versus neutron number spectra of normal nuclei, and the hyperon-separation
energies from hypernuclei. The drip lines are modified for addition of a
hyperon in a normal nucleus.Comment: Presented at the "XXIX Mazurian Lakes Conference on Physics: Nuclear
Physics and the Fundamental Processes, Piaski, Poland, August 30 - September
6, 2005." (7 pages, 1 Table, 1 Figure
Alpha decay half-lives of new superheavy elements
The lifetimes of decays of the recently produced isotopes of the
elements 112, 114, 116 and the element and of some decay products
have been calculated theoretically within the WKB approximation using
microscopic -nucleus interaction potentials. These nuclear potentials
have been obtained by folding the densities of the and the daughter
nuclei with the M3Y effective interaction, supplemented by a zero-range
pseudo-potential for exchange along with the density dependence. Spherical
charge distributions have been used for calculating the Coulomb interaction
potentials. These calculations provide reasonable estimates for the observed
decay lifetimes and thus provide reliable predictions for other
superheavies.Comment: 7 page
Folding model analysis of proton radioactivity of spherical proton emitters
Half lives of the decays of spherical nuclei away from proton drip line by
proton emissions are estimated theoretically. The quantum mechanical tunneling
probability is calculated within the WKB approximation. Microscopic
proton-nucleus interaction potentials are obtained by single folding the
densities of the daughter nuclei with M3Y effective interaction supplemented by
a zero-range pseudo-potential for exchange along with the density dependence.
Strengths of the M3Y interaction are extracted by fitting its matrix elements
in an oscillator basis to those elements of the G-matrix obtained with the
Reid-Elliott soft-core nucleon-nucleon interaction. Parameters of the density
dependence are obtained from the nuclear matter calculations. Spherical charge
distributions are used for calculating the Coulomb interaction potentials.
These calculations provide reasonable estimates for the observed proton
radioactivity lifetimes of proton rich nuclei for proton emissions from 26
ground and isomeric states of spherical proton emitters.Comment: 6 page
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