3rd Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 54, Number 10
Tuesday–Saturday, October 13–17, 2009;
Waikoloa, Hawaii
Session GB: Conference Experience for Undergraduates Poster Session (1:00-3:00 PM)
1:00 PM,
Friday, October 16, 2009
Room: Grand Promenade
Chair: Warren Rogers, Westmont College
Abstract ID: BAPS.2009.HAW.GB.20
Abstract: GB.00020 : Nuclear Structure in Even-Even Nuclei, $24\le Z\le 72$*
Preview Abstract
Abstract
Author:
Sarah Buchhorn
(HSHSP-MSU)
Analysis of the spectra of excited nuclei has been used for
decades to reveal trends and build models. Power regressions of
the form $E(J)=a(\sqrt {J(J+1)} )^b$ fitted to the \textit{yrast}
line of isotopes reveal an average $b$ of $_{\sim
}\raise0.5ex\hbox{$\scriptstyle
4$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 3$}$.
It should be noted that this is the value predicted for large
angular momenta by the Variable Moment of Inertia model [1,2]. A
second plot of $\mathop R\nolimits_J \quad (\mathop R\nolimits_J
=\mathop E\nolimits_{\mathop J\nolimits_1^+ } /\mathop
E\nolimits_{\mathop 2\nolimits_1^+ } )$ vs. $J$ reveals curves
described by power regressions where $0.66\le b\le 1.81$. Graphs
of $b$ vs. neutron number ($N)$ reveal V-shaped patterns for many
nuclei, with the lowest exponent corresponding to a magic $N$. In
addition, sharp jumps in exponents are seen at the $(N=88)\to
(N=90)$ transition point in several nuclei. A third chart -- an
abbreviated energy level diagram including $\mathop
0\nolimits_1^+ $,$\mathop 0\nolimits_2^+ $,$\mathop
2\nolimits_1^+ $,$\mathop 2\nolimits_2^+ $, and $\mathop
4\nolimits_1^+ $states illustrates the energy increases at magic
numbers, along with the near-degenerate two-phonon triplet of
$\mathop 0\nolimits_2^+ $, $\mathop 2\nolimits_2^+ $, and
$\mathop 4\nolimits_1^+ $ - most clearly observed in isotopes of
Z=28,34,36,38,44,46, and 48. Lastly, a fourth chart of $\mathop
E\nolimits_{\mathop 3\nolimits_1^- } $ against $\mathop
E\nolimits_{\mathop 2\nolimits_1^+ } $ shows positive correlation
that is well described by equation $E(\mathop 3\nolimits^-
)=A-\frac{\mathop B\nolimits^2 }{E(\mathop 2\nolimits_1^+ )}$ -
not only for Z=54 [3] but also for Z=36,42-52, and 68. Data
obtained through ENSDF database. [1]
M.A.J.Mariscotti,G.Sharff-Goldhaber and B.Buck,
\textit{Phys.Rev.}\textbf{178,1864}(1969). [2] M.I. Stockmann and
V.G.Zelevinsky, \textit{Phys.Lett.}\textbf{41B},19(1972). [3]
W.F. Mueller et al.,\textit{Phys.Rev.C} \textbf{73}, 014316(2006).
*Research advisor Vladimir Zelevinsky is gratefully acknowledged.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.HAW.GB.20