Measurement of Hyperfine Structure and the Zemach Radius in

We investigate the 2^{3}S_{1}-2^{3}P_{J} (J=0, 1, 2) transitions in ^{6}Li^{+} using the optical Ramsey technique and achieve the most precise values of the hyperfine splittings of the 2^{3}S_{1} and 2^{3}P_{J} states, with smallest uncertainty of about 10 kHz. The present results reduce the uncertainties of previous experiments by a factor of 5 for the 2^{3}S_{1} state and a factor of 50 for the 2^{3}P_{J} states, and are in better agreement with theoretical values. Combining our measured hyperfine intervals of the 2^{3}S_{1} state with the latest quantum electrodynamic (QED) calculations, the improved Zemach radius of the ^{6}Li nucleus is determined to be 2.44(2) fm, with the uncertainty entirely due to the uncalculated QED effects of order mα^{7}. The result is in sharp disagreement with the value 3.71(16) fm determined from simple models of the nuclear charge and magnetization distribution. We call for a more definitive nuclear physics value of the ^{6}Li Zemach radius.

Precision Spectroscopy of the Pionic Helium-4.

The transition frequency of (n,ℓ)=(17,16)→(16,15) in pionic helium-4 is calculated to an accuracy of 4 ppb (parts per billion), including relativistic and quantum electrodynamic corrections up to O(R_{∞}α^{5}). Our calculations significantly improve the recent theoretical values [Hori et al., Phys. Rev. A 89, 042515 (2014)PLRAAN1050-294710.1103/PhysRevA.89.042515]. In addition, collisional effects between pionic helium and target helium on transition frequencies are estimated. Once measurements reach the ppb level, our Letter will improve the value of the π^{-} mass by 2-3 orders of magnitude.

Precision Calculation of Hyperfine Structure and the Zemach Radii of

The hyperfine structures of the 2^{3}S_{1} states of the ^{6}Li^{+} and ^{7}Li^{+} ions are investigated theoretically to extract the Zemach radii of the ^{6}Li and ^{7}Li nuclei by comparing with precision measurements. The obtained Zemach radii are larger than the previous values of Puchalski and Pachucki [Phys. Rev. Lett. 111, 243001 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.243001] and disagree with them by about 1.5 and 2.2 standard deviations for ^{6}Li and ^{7}Li, respectively. Furthermore, our Zemach radius of ^{6}Li differs significantly from the nuclear physics value, derived from the nuclear charge and magnetic radii [Phys. Rev. A 78, 012513 (2008)PLRAAN1050-294710.1103/PhysRevA.78.012513] by more than 6σ, indicating an anomalous nuclear structure for ^{6}Li. The conclusion that the Zemach radius of ^{7}Li is about 40% larger than that of ^{6}Li is confirmed. The obtained Zemach radii are used to calculate the hyperfine splittings of the 2^{3}P_{J} states of ^{6,7}Li^{+}, where an order of magnitude improvement over the previous theory has been achieved for ^{7}Li^{+}.

Oscillator strengths between low-lying ro-vibrational states of hydrogen molecular ions.

It is important for experimental design to know the transition oscillator strengths in hydrogen molecular ions. In this work, for HD(+), HT(+), and DT(+), we calculate the ro-vibrational energies and oscillator strengths of dipole transitions between two ro-vibrational states with the vibrational quantum number ν = 0-5 and the total angular momentum L = 0-5. The oscillator strengths of HT(+) and DT(+) are presented as supplementary material.

[Establishment and characterization of serial subpopulations with highly metastatic potential via different metastatic routes].

OBJECTIVE: To establish the serial cell lines, derived from the same parental gallbladder cancer cell line GBC-SD, with highly metastatic potential via different routes and characterize their biological behaviors to understand the different metastasis mechanisms via lymph and blood. METHODS: The spleen-liver metastasis model and footpad-inguinal lymph node metastasis model were established. GBC-SD was injected into spleen or footpad of nude mice. Then the highly metastasized subpopulations via lymph and blood were isolated. Their differences in morphology, genetic background, proliferation, migration, invasion and adhesion were revealed by comparing the lymphatic-disseminating and hematogenous-disseminating subpopulations with parental cells. RESULTS: The lymphatic-disseminating and hematogenous-disseminating subpopulations were successfully isolated and designated as GBC-SD/HL and GBC-SD/M3 respectively. They demonstrated the identical genetic background with GBC-SD. In comparison with parental cells, the hematogenous-disseminating subpopulation was morphologically characterized with epithelial-mesenchymal transition (EMT) while it was not shown in the lymphatic-disseminating subpopulation. Furthermore, the hematogenous-disseminating subpopulation showed the strongest migrating capacity but the lymphatic-disseminating subpopulation demonstrated a stronger invasive and adhesive ability. CONCLUSION: The whole parental cell GBC-SD, hematogenous-metastasized subpopulation GBC-SD/M3 and lymphatic-disseminating subpopulation GBC-SD/HL is an ideal tool for metastatic mechanism study of gallbladder cancer. EMT plays an important role in hematogenous metastasis while lymphatic metastasis relies more on enhanced invasiveness and adhesion. It may be a target for interfering the lymphatic metastasis of gallbladder cancer.