Evolution of deformation in neutron-rich Ba isotopes up to A=150

The occurrence of octupolar shapes in the Ba isotopic chain was recently established experimentally up to N = 90. To further extend the systematics, the evolution of shapes in the most neutron-rich members of the Z = 56 isotopic chain accessible at present, Ba-148,Ba-150, has been studied via beta decay at the ISOLDE Decay Station. This paper reports on the first measurement of the positive-and negative-parity low-spin excited states of 150Ba and presents an extension of the beta-decay scheme of Cs-148. Employing the fast timing technique, half-lives for the 2(1)(+) level in both nuclei have been determined, resulting in T-1/2 = 1.51(1) ns for Ba-148 and T-1/2 = 3.4(2) ns for Ba-150. The systematics of low-spin states, together with the experimental determination of the B(E2 : 2(+) -> 0(+)) transition probabilities, indicate an increasing collectivity in Ba148-150, towards prolate deformed shapes. The experimental data are compared to symmetry conserving configuration mixing (SCCM) calculations, confirming an evolution of increasingly quadrupole deformed shapes with a definite octupolar character.Peer reviewe

Lifetime measurements of the low-lying excited states of ²⁰⁸Po

In this study we present the preliminary results about the lifetimes of the 2₂⁺, 4₁⁺ states of ²⁰⁸Po and the upper limit of the lifetime of the 2₁⁺ state. For measuring the lifetimes of the 2₁⁺ and 4₁⁺ states the Recoil Distance Doppler Shift (RDDS) method and for the lifetime of the 2₂⁺ state the Doppler Shift Attenuation method (DSAM) were used. The resulting absolute transition strength B(M1 ; 2₂⁺ → 2₁⁺) ≥ 0.122(20) μN² reveals the predominant isovector nature of the 2₂⁺ state of ²⁰⁸Po

Information demand and stock return predictability

Recent theoretical work suggests that signs of asset returns are predictable given that their volatilities are. This paper investigates this conjecture using information demand, approximated by the daily internet search volume index (SVI) from Google. Our results reveal that incorporating the SVI variable in various GARCH family models significantly improves volatility forecasts. Moreover, we demonstrate that the sign of stock returns is predictable contrary to the levels, where predictability has proven elusive in the US context. Finally, we provide novel evidence on the economic value of sign predictability and show that investors can form profitable investment strategies using the SVI

Experimental evidence for low-lying quadrupole isovector excitation of Po-208

We present the results from an experiment dedicated to measure the lifetime of the 2(2)(+) state, candidate for the one-phonon mixed-symmetry state, of Po-208. This nucleus was studied in the a-transfer reaction Pb-204(C-12,Be-8)208Po and the lifetime of the 2(2)(+) state was determined by utilizing the Doppler-shift attenuation method. The experimental data show that the 2(2)(+) state decays with a sizable M1 transition to the 2(1)(+) state revealing its isovector nature