Observation of the nuclear magnetic octupole moment of173Yb from precise measurements of the hyperfine structure in the3P2state

Abstract

We measure hyperfine structure in the metastable 3 P 2 state of 173 Yb and extract the nuclear magnetic octupole moment. We populate the state using dipole-allowed transitions through the 3 P 1 and 3 S1 states. We measure frequencies of hyperfine transitions of the 3 P 2 → 3 S1 line at 770 nm using a Rb-stabilized ring cavity resonator with a precision of 200 kHz. Second-order corrections due to perturbations from the nearby 3 P 1 and 1 P 1 states are below 30 kHz. We obtain the hyperfine coefficients as: A = −742.11(2) MHz, B = 1339.2(2) MHz, which represent two orders-of-magnitude improvement in precision, and C = 0.54(2) MHz. From atomic structure calculations, we obtain the nuclear moments: quadrupole Q = 2.46(12) b and octupole Ω = −34.4(21) b ×µN .

Magnetic octupole moment of Yb173 using collinear laser spectroscopy

“…As can be seen, the CV and CC correlations make significant contributions to these constants. Comparing our results with other recent measurement and calculations by Porsev et al [32] and Singh et al [22], we found an excellent agreement for the A constant. However, this may be an accidental accidental since μ I = −0.648(3) μ N from Ref.…”

“…It was found from Table I that the present B/Q constant differs from theirs by about 9%, which is in better agreement than that from Ref. [22]. For the latter the deviation reaches 14%.…”

“…In addition, the value of obtained in Ref. [22] is considerably larger than a single-particle shell model estimate. This implies a puzzling deficiency in our understanding of the nuclear electromagnetic moments.…”

“…Yet another example was reported in Ref. [22], where the of Yb was extracted from the hyperfine intervals in the 4 f 14 6s6p 3 P o 2 state of 173 Yb (with nuclear spin I = 5/2 − ). This latter measurement is of particular interest, since a large octupole splitting was observed, and a correspondingly large value of was thus obtained.…”

“…In this work, however, we seek to validate the measurements in Ref. [22] using collinear laser spectroscopy, which is the standard tool for high-resolution optical spectroscopy of radioactive beams. A successful measurement of a nonzero magnetic octupole constant using this method would pave the way for future measurements on radioactive ytterbium isotopes.…”