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Register a new userGlobal analysis of data on the spin-orbit coupled $A^{1}Sigma_{u}^{+}$ and $b^{3}Pi_{u}$ states of Cs2
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We present experimentally derived potential curves and spin-orbit interaction functions for the strongly perturbed $A^{1}Sigma_{u}^{+}$ and $b^{3}Pi_{u}$ states of the cesium dimer. The results are based on data from several sources. Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used some time ago in the Laboratoire Aim{e} Cotton primarily to study the $X ^{1}Sigma_{g}^{+}$ state. More recent work at Tsinghua University provides information from moderate resolution spectroscopy on the lowest levels of the $b^{3}Pi_{0u}^{pm}$ states as well as additional high resolution data. From Innsbruck University, we have precision data obtained with cold Cs$_{2}$ molecules. Recent data from Temple University was obtained using the optical-optical double resonance polarization spectroscopy technique, and finally, a group at the University of Latvia has added additional LIF FTS data. In the Hamiltonian matrix, we have used analytic potentials (the Expanded Morse Oscillator form) with both finite-difference (FD) coupled-channels and discrete variable representation (DVR) calculations of the term values. Fitted diagonal and off-diagonal spin-orbit functions are obtained and compared with {it ab initio} results from Temple and Moscow State universities.
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We present the first spectroscopic studies of the $C ^1Sigma^+$ electronic state and the $A ^1Sigma^+$ - $b ^3Pi_{0^+}$ complex in $^7$Li - $^{85}$Rb. Using resonantly-enhanced, two-photon ionization, we observed $v = 7$, 9, 12, 13 and $26-44$ of the $C ^1Sigma^+$ state. We augment the REMPI data with a form of depletion spectra in regions of dense spectral lines. The $A ^1Sigma^+$ - $b ^3Pi_{0^+}$ complex was observed with depletion spectroscopy, depleting to vibrational levels $v=0 rightarrow 29$ of the $A ^1Sigma^+$ state and $v=8 rightarrow 18$ of the $b ^3Pi_{0^+}$ state. For all three series, we determine the term energy and vibrational constants. Finally, we outline several possible future projects based on the data presented here.
Polarisation labelling spectroscopy technique was employed to study the 3$^{1}Pi_{u}$ state of Cs$_2$ molecule. The main equlibrium constants are $T_e=20684.60$cm$^{-1}$, $omega_e=30.61$cm$^{-1}$ and $R_e=5.27$r{A}. Vibrational levels $v=4-35$ of the 3$^{1}Pi_{u}$ state were found to be subject to strong perturbations by the neighbouring electronic states. Energies of 3094 rovibronic levels of the perturbed complex were determined.
We present results of a combined analysis in neutrino oscillations without unitarity assumption in the $3 u$ mixing picture. Constraints on neutrino mixing matrix elements are based on recent data from the reactor, solar and long-baseline accelerator neutrino oscillation experiments. The current data are consistent with the standard $3 u$ scheme. The precision on different matrix elements can be as good as a few percent at $3sigma$ CL, and is mainly limited by the experimental statistical uncertainty. The $ u_e$ related elements are the most precisely measured among all sectors with the uncertainties $<20%$. The measured leptonic CP violation is very close to the one assuming the standard $3 u$ mixing. The deviations on normalization and the unitarity triangle closure are confined within $mathcal{O}(10^{-3})$, $mathcal{O}(10^{-2})$ and $mathcal{O}(10^{-1})$, for $ u_e$, $ u_{mu}$ and $ u_{tau}$ sectors, respectively. We look forward to the next-generation neutrino oscillation experiments textit{such as} DUNE, T2HK, and JUNO, especially the precise measurements on $ u_tau$ oscillations, to significantly improve the precision of unitarity test on the $3 u$ mixing matrix.
We combined high-resolution Fourier-transform spectroscopy and large-scale electronic structure calculation to study energy and radiative properties of the high-lying (3)1{Pi} and (5)1{Sigma}+ states of the RbCs molecule. The laser-induced (5)1{Sigma}+(4)1{Sigma}+(3)1{Pi}-A(2)1{Sigma}+ b(1)3{Pi} fluorescence (LIF) spectra were recorded by the Bruker IFS-125(HR) spectrometer in the frequency range { u} 5500 to 10000cm-1 with the instrumental resolution of 0.03 cm-1. The rotational assignment of the observed LIF progressions, which exhibit irregular vibrational-rotational spacing due to strong spin-orbit interaction between A1{Sigma}+ and b3(Pi) states was based on the coincidences between observed and calculated energy differences. The required rovibronic term values of the strongly perturbed A-b complex have been calculated by a coupled-channels approach for both 85Rb133Cs and 87Rb133Cs isotopologs with accuracy of about 0.01 cm-1, as demonstrated in A. Kruzins et al. [J. Chem. Phys. 141, 184309 (2014)]. The experimental energies of the upper (3)1(Pi) and (5)1{Sigma}+ states were involved in a direct-potential-fit analysis performed in the framework of inverted perturbation approach. Quasirelativistic ab initio calculations of the spin-allowed (3)1{Pi},(5)1{Sigma}+- (1-4)1{Sigma}+(1-3)1{Pi} transition dipole moments were performed. Radiative lifetimes and vibronic branching ratios of radiative transitions from the (3)1{Pi} and (5)1{Sigma}+ states were evaluated. To elucidate the origin of the {Lambda}-doubling effect in the (3)1{Pi} state, the angular coupling (3)1{Pi}-(1-5)1{Sigma}+ electronic matrix elements were calculated and applied for the relevant q-factors estimate. The intensity distributions simulated for the particular (5)1{Sigma}+(3)1{Pi}-A-b LIF progressions have been found to be remarkably close to their experimental counterparts.
The hitherto unobserved purely leptonic decays B^pm -> tau^pm u and B^pm -> mu^pm u are of much interest at current and future runs of the e+e- B factories. Such decays are sensitive to charged Higgs bosons (H^pm) at the tree-level and provide essentially model independent constraints on tanbeta/m_{H^pm}. We include the large corrections to the H^pm-ub coupling induced by virtual SUSY effects and show that the bounds on tanbeta/m_{H^pm} can be significantly weakened or strengthened.
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