Configuration Mixing for Po Isotopes within the Interacting Boson Model-2

We analyze a sequence of 194−204Po isotopes, using the Configuration Mixing (CM) Interacting Boson Model 2 (IBM-2). We set the parameters of Hamiltonian using a least-square fit for the known energy levels, electrical transition rates B(E2), and quadruple moments Q(2+1) for the first excited states. We have a good agreement with the experimental values for all the observables tested, and we infer that the feature of the shape coexistence is concealed in the isotopes of Po, just as in the isotopes of Os and Pt.

Lifetime measurements in $$^{182}\hbox {Pt}$$ using $$\gamma $$–$$\gamma $$ fast-timing

The level lifetimes of the $$2_1^+$$ 2 1 + and $$4_1^+$$ 4 1 + states in $$^{182}\hbox {Pt}$$ 182 Pt have been re-measured employing the $$\gamma $$ γ –$$\gamma $$ γ fast-timing technique using fast $$\hbox {LaBr}_3$$ LaBr 3 (Ce) scintillators. Excited states in the nucleus of interest were populated by the fusion-evaporation reaction $$^{170}\hbox {Yb}(^{16}\hbox {O},\hbox {4n})^{182}\hbox {Pt}$$ 170 Yb ( 16 O , 4n ) 182 Pt at a beam energy of 87 MeV provided by the FN Tandem accelerator of the University of Cologne. The lifetime of the $$2_1^+$$ 2 1 + state was re-measured with high accuracy to be $$\tau = 563(12)~$$ τ = 563 ( 12 ) ps and resolves inconsistencies from previous measurements. Experimental results are compared to theoretical calculations in the framework of the sd-IBM with and without configuration mixing.

Impact of uncertainties of unbound 10Li on the ground state of two-neutron halo 11Li

Recently, the energy spectrum of \boldsymbol{^{10}}10Li was measured upto \boldsymbol{4.6}4.6 MeV, via one-neutron transfer reaction \boldsymbol{d(^{9}\textrm{Li},~p)^{10}\textrm{Li}}𝐝(9Li,𝐩)10Li. Considering the ambiguities on the \boldsymbol{^{10}}10Li continuum spectrum with reference to new data, we report the configuration mixing in the ground state of the two-neutron halo nucleus \boldsymbol{^{11}}11Li for two different choices of the \boldsymbol{^{9}{\textrm{Li}}+n}9Li+𝐧 potential. For the present study, we employ a three-body (\boldsymbol{\textrm{core}+n+n}core+𝐧+𝐧) structure model developed for describing the two-neutron halo system by explicit coupling of unbound continuum states of the subsystem (\boldsymbol{\textrm{core}+n}core+𝐧), and discuss the two-neutron correlations in the ground state of \boldsymbol{^{11}}11Li.