Radial Excitations of Heavy Mesons

Recent discovery of D_s states suggests existence of radial excitations. Our semirelativistic quark potential model succeeds in reproducing these staes within one to two percent of accuracy compared with the experiments, D_s0(2860) and D_s^*(2715), which are identified as 0^+ and 1^- radial excitations (n=2). We also present calculations of radial excitations for B/B_s heavy mesons. Relation between our formulation and the modified Goldberger-Treiman relation is also described.Comment: 3 pages, 1 figure, QNP06 conference repor

Manipulating ionization path in a Stark map: Stringent schemes for the selective field ionization in highly excited Rb Rydberg atoms

We have developed a quite stringent method in selectivity to ionize the low angular- momentum ($\ell$) states which lie below and above the adjacent manifold in highly excited Rb Rydberg atoms. The method fully exploits the pulsed field-ionization characteristics of the manifold states in high slew-rate regime: Specifically the low $\ell$ state below (above) the adjacent manifold is firstly transferred to the lowest (highest) state in the manifold via the adiabatic transition at the first avoided crossing in low slew-rate regime, and then the atoms are driven to a high electric field for ionization in high slew-rate regime. These extreme states of the manifold are ionized at quite different fields due to the tunneling process, resulting in thus the stringent selectivity. Two manipulation schemes to realize this method actually are demonstrated here experimentally.Comment: 10 pages, 4 figure

Systematic observation of tunneling field-ionization in highly excited Rb Rydberg atoms

Pulsed field ionization of high-$n$ (90 $\leq n \leq$ 150) manifold states in Rb Rydberg atoms has been investigated in high slew-rate regime. Two peaks in the field ionization spectra were systematically observed for the investigated $n$ region, where the field values at the lower peak do not almost depend on the excitation energy in the manifold, while those at the higher peak increase with increasing excitation energy. The fraction of the higher peak component to the total ionization signals increases with increasing $n$, exceeding 80% at $n$ = 147. Characteristic behavior of the peak component and the comparison with theoretical predictions indicate that the higher peak component is due to the tunneling process. The obtained results show for the first time that the tunneling process plays increasingly the dominant role at such highly excited nonhydrogenic Rydberg atoms.Comment: 8 pages, 5 figure