Speaker
Description
In our previous papers, we extensively studied odd-odd nuclei adjacent to doubly
magical stable nuclide $^{208}$Pb, as well as to also doubly magical neutron excess
$^{132}$Sn. To date, some experimental information has emerged also about the
properties of such nuclei in the vicinity of an extremely neutron deficient and
also doubly magical $^{100}$Sn. In our calculations of odd-odd nuclei close to
$^{100}$Sn, we applied random phase
approximation and multi-particle shell model, both based on the phenomenological
nuclear potential [1] and effective two-body interaction [2], which parameters were
defined by us before. The subject of our interest were $^{98}_{49}$In$_{49}$,
$^{100}_{49}$In$_{51}$, $^{98}_{47}$Ag$_{51}$ and $^{94}_{45}$Rh$_{49}$. In these
nuclei we determined energy spectra and $E2, M1$ transition rates. Effective
transition operators were also defined by us before [3], and they successfully
described $E2$ and $M1$ transitions in nuclei close to $^{208}$Pb and $^{132}$Sn.
In particular, the values of proton and neutron effective charges were $e_p = 1.6|e|$
and $e_n = 0.9|e|$. In our case, the value of $e_p \approx 1.6|e|$ was also obtained
by us by using the experimental $T_{1/2}$ values of the $8^{+}_{1} \to 6^{+}_{1}$
and $6^{+}_{1} \to 4^{+}_{1}$ transitions in $^{98}_{48}$Cd$_{50}$ [4], as well as our
RPA calculation for these cases. However, the energy of an analogous $6^{+}_{1}
\to 4^{+}_{1}$ transition and its half-life in $^{102}_{50}$Sn$_{52}$ are known with
great uncertainty [4, 5] and thus the value of neutron effective charge in nuclei
close to$^{100}$Sn is also very uncertain [5]: $e_n = 2.3(+0.6 -0.2)|e|$. Such a
large value of neutron effective charge is a subject of discussions. Here, we defined
the values of $e_p$ and $e_n$ from the joint description of the $4^{+}_{1} \to
6^{+}_{1}(gr.st.)$ and $2^{+}_{1} \to 4^{+}_{1}(gr.st.)$ transitions in $^{98}$Ag
and $^{94}$Rh. The result is $e_p \approx 1.6$ and $e_n \approx 2.8$. Mention that
the obtained by us value of $e_n$ agrees with the experimental results [6, 7],
considered together with theoretical calculations performed by us for the
$6^{+}_{1} \to 4^{+}_{1}$ transition in $^{102}$Sn [2].
- V. I. Isakov et al., Eur. Phys. J. A {\bf14}, 29 (2002).
- V. I. Isakov, Phys. At. Nucl. {\bf76}, No 7, 828 (2013).
- S. A. Artamonov, et al., Sov. J. Nucl. Phys. {\bf36}, No 4, 486 (1982).
- https://www-nds.bnl.gov/ensdf/
- M. Lipoglav$\breve{s}$ek et al., Phys. Lett. B {\bf440}, 246 (1998).
- T. Faestermann, {\em Spectroscopy of N $\sim$ Z Nuclei:
$^{100}$Sn and Neighbours}, https://indico.ific.\uv.es/event/349/contributions/6172/
attachments/4036/4532/Faestermann.pdf, 24 (2011). - M. G$\acute{o}$rska, {\em Recent results in the region of $^{100}$Sn}, https://indico.in2p3.fr/
event/12970/\contriburions/12367/attachments/10498/13010/SSNET$\_$gorska$\_$2016$\_$2.pdf, 36 (2016).
