Stable triaxiality at the highest spins in138Ndand139Nd

Tilted axis rotation, candidates for chiral bands, and wobbling motion in138Nd

“…The energies, relative intensities, DCO ratios and spin-parity assignments of the observed transitions are reported in Table I. The spectroscopic data on 138 Nd are very much enriched with respect to the previous studies [11,[17][18][19][20][21]. The newly constructed level scheme will be discussed separately for the bands of quadrupole and dipole transitions.…”

“…These exotic types of motion were observed in specific regions of the nuclear chart: the wobbling motion in the odd-even Lu nuclei with A ∼ 160 [6], the chirality primarly in the odd-odd and odd-even nuclei with A ∼ 130 nuclei [4,7,8]. In the nuclei 136−140 Nd, surrounding the subject of the present paper, the rotational bands at medium and high spins have been successfully interpreted with model calculations based on triaxial shapes [9][10][11][12][13]. In the same mass region nearly degenerate bands with the same spin and parity have been observed, which were interpreted as chiral partners (for example 134 Pr and 135 Nd [4,7,8]).…”

“…• , which is a typical value for this mass region [9][10][11][12][13]. The TAC model considers the rotation about an axis that is tilted by the angles θ and φ from the principal axes.…”

“…Refs. [11][12][13] proposed stable triaxiality at high-spin in 138,139,140 Nd. A highly-deformed band in 138 Nd and a superdeformed (SD) band in 140 Nd were suggested in Refs.…”

“…High-spin states in 138 Nd have been previously studied by Müller-Veggian et al [19,20] and de Angelis et al [21] up to spin 19 and 21 , respectively. More recently, four high-spin bands were observed in 138 Nd using the 94 Zr( 48 Ca,4n) reaction at an energy 195 MeV [11]. Gamma-ray coincidences were measured with the 8π spectrometer consisting of 20 Ge detectors with anti-Compton shields and an inner ball of 71 BGO scintillator detectors.…”