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تسجيل مستخدم جديدSuperdeformation in $^{198}$Po
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The $^{174}$Yb($^{29}$Si,5n) reaction at 148 MeV with thin targets was used to populate high-angular momentum states in $^{198}$Po. Resulting $gamma$ rays were observed with Gammasphere. A weakly-populated superdeformed band of 10 $gamma$-ray transitions was found and has been assigned to $^{198}$Po. This is the first observation of a SD band in the $A approx 190$ region in a nucleus with $Z > 83$. The ${cal J}^{(2)}$ of the new band is very similar to those of the yrast SD bands in $^{194}$Hg and $^{196}$Pb. The intensity profile suggests that this band is populated through states close to where the SD band crosses the yrast line and the angular momentum at which the fission process dominates.
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Low lying states of $^{198}$Hg have been investigated via $^{197}$Au($^{7}$Li, $ alpha $2n$ gamma $)$ ^{198} $Hg reaction at E$ _{text{beam}} $ = 33 MeV and 38 MeV and the members of $ gamma $-vibrational band have been identified. Results are compar
ed with the systematic of this mass region and found in agreement. Observed band structures have been interpreted using the theoretical framework of microscopic triaxial projected shell model (TPSM) approach and it is shown that TPSM results are in fair agreement with the observed energies.
A superdeformed (SD) band has been identified in a non - alpha - conjugate nucleus 35Cl. It crosses the negative parity ground band above 11/2- and becomes the yrast at 15/2-. Lifetimes of all relevant states have been measured to follow the evolutio
n of collectivity. Enhanced B(E2), B(E1) values as well as energetics provide evidences for superdeformation and existence of parity doublet cluster structure in an odd-A nucleus for the first time in A = 40 region. Large scale shell model calculations assign (sd)16(pf)3 as the origin of these states. Calculated spectroscopic factors correlate the SD states in 35Cl to those in 36Ar.
Results of a comparative analysis of the $^{214}$Po ($T_{1/2}= 163.47pm0.03$ $mu$s), $^{213}$Po ($T_{1/2}=3.705 pm 0.001$ $mu$s) and $^{212}$Po ($T_{1/2}=294.09pm0.07$ ns) half-life annular variation parameters are presented. It is shown that two ind
ependent sequential sets of the $^{214}$Po $tau$-values $(tauequiv T_{1/2})$ obtained in the spaced laboratories can be described by sinusoidal functions. The sinusoid curve with amplitude $A=(5.0 pm1.5) cdot 10^{-4}$, period $omega=(365pm 8)$ days, and phase $phi=(170 pm 7)$ days approximates the set of $^{214}$Po $tau$ values obtained at BNO INR RAS during the $sim$973 days starting on January 4, 2012. The function approximates a set of $tau$-values with a time duration of $sim1460$ days obtained at the KhNU has an amplitude $A=(4.9pm1.8)cdot10^{-4}$, a period $omega= (377pm13)$ days and a phase $phi=(77pm10)$ days. The $^{213}$Po $tau$-value set with a time duration of $sim1700$ days can be described by a sinusoidal function with an amplitude $A=(3.9pm1.2)cdot10^{-4}$, a period $omega= (370pm13)$ days and a phase $phi=(130pm9)$ days. The $^{212}$Po $tau$-value set with a time duration of $sim670$ days can be described by a sinusoidal function with an amplitude $A=(7.5pm1.6)cdot10^{-4}$, a period $omega= (375pm13)$ days and a phase $phi=(40pm10)$ days.
High-spin states in the doubly-odd $^{198}$Bi nucleus have been studied by using the $^{185,187}$Re($^{16}$O, xn) reactions at the beam energy of 112.5 MeV. $gamma-gamma$ coincidence were measured by using the INGA array with 15 Compton suppressed cl
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