High-resolution spectroscopy of the v2 = 2 a ← v2 = 1 s band of 14NH3

Twenty-one transitions of the v₂ = 2 a ← v₂ = 1 s hot band of ¹⁴NH₃ have been observed by an infrared microwave sideband laser spectrometer with an absolute accuracy of 0.00002 cm⁻¹. One hundred and seventeen transitions of the band have been obtained by a Fourier transform infrared spectrometer at a resolution of 0.005 cm⁻¹. A weighted least-squares analysis of these data has been carried out to yield 17 molecular parameters for the v₂ = 2 a state. These parameters reproduce the experimental frequencies with a root mean square deviation of 0.000123 cm⁻¹. To calculate the frequencies to this accuracy it was necessary to take into account the Δ(K − l) = ±3 interaction between the v₂ = 2 a and v₄ = 1 a states.     

High-resolution spectroscopy of the v2 = 2 a ← v2 = 1 s band of 15NH3

Twenty-four transitions of the v₂ = 2 a ← v₂ = 1 s hot band of ¹⁵NH₃ have been observed by an infrared microwave sideband laser spectrometer. In addition, 149 transitions of the band have been obtained by a Fourier transform spectrometer at a resolution of 0.02 cm⁻¹. A weighted least-squares analysis has been carried out and the rms deviation of the fit is 0.00097 cm⁻¹. It was necessary to include the Δ(K − l) = ±3 interaction between the v₂ = 2 a and the v₄ = a states in the analysis.     

The spectrum of a Schrödinger operator inL p ℝ v isp-independent

LetH _p =–1/2+V denote a Schrödinger operator, acting inL _p ^v , 1p. We show that (H _p )=(H ₂) for allp[1, ], for rather general potentialsV.     

Rotational analysis of the v 2 + v 6 ±1, v 5 ∓1 + v 6 ∓1 and v 5 ∓1 + v 6 ±1 interacting infrared bands of methyl bromide

The rotational analysis of the infrared absorption spectrum of CH₃ ⁷⁹Br and CH₃ ⁸¹Br between 2150 and 2510 cm^-1 was performed on a Fourier transform spectrum with a resolution of 0·007 cm^-1. The bands v ₂ + v ₆(E) and v ₅ + v ₆(A ₁ + A ₂ + E) occur in this region, giving rise to several perturbations as in the corresponding system of methyl chloride [3]. Forbidden transitions, observed in correspondence of the level crossing of the x-y Coriolis coupling between v ₂ + v ₆ and v ₅ + v ₆(E), enabled us to estimate the value of A″ - 225D″_K at 5·16186 cm^-1 for CH₃ ⁷⁹Br and 5·16173 cm^-1 for CH₃ ⁸¹Br. The parallel system of v ₅ + v ₆ exhibits a perpendicular structure, and an l-type resonance couples those levels of the parallel and perpendicular components of v ₅ + v ₆ involved in transitions from the K″ = 0 levels of the ground state. The ^QQ ₀ branches of the A ₂ component of v ₅ + v ₆, made active by this resonance, are observed for both isotopic species.     

Effects of vector leptoquarks on Ab →Acl(v)l decay

Experimental data on R(D(*)),R(K(*)),and R(J/ψ),provided by different collaborations,show sizable deviations from the standard model predictions.To describe the...     

The S21 lines of the A2Σ+ (v′ = 1)←X2Π (v″ = 0) transitions of OH and OD

The S₂₁ lines of the OH radical for the A²Σ⁺ (v′ = 1)←X²Π (v″ = 0) transition have been observed in the 278–280 nm region from the laser-excitation spectrum. The OH radical was generated from either the H + NO₂ or the H + O₃ reaction in a flow system and the fluorescence passing through a 309.6 nm interference filter was detected with a photomultiplier-boxcar integrator arrangement. The weak S₂₁ lines were observed at laser energies above 0.2 mJ. The observed peak wavenumbers are in excellent agreement with those predicted for the S₂₁ bands of the A (v>′ = 1)←X (v″ = 0) transition from the known spectroscopic parameters. Observation of the corresponding S₂₁ system for OD in the 286.0–286.9 nm region further confirms this assignment. The relative absorption cross-sections of about one-tenth those of the P₁ lines are in good agreement with theoretical considerations.     

Bounds on the magnetic moment of the τ-neutrino via the process e+e-→v(v)γ

Using Breit-Wigner resonance relation,bounds on the magnetic moment of the tau-neutrino are calculated through the reaction e+e-→v(v)γ at the neutral boson pole in the framework of a superstringinspired E6 model which has one extra low-energy neutral gauge boson and a LRSM.     

Realization of a SU(2)×SU(6) system of fermions in a cold atomic gas

We report the realization of a novel degenerate Fermi mixture with an SU(2)×SU(6) symmetry in a cold atomic gas. We successfully cool the mixture of the two fermionic isotopes of ytterbium 171Yb with the nuclear spin I=1/2 and 173Yb with I=5/2 below the Fermi temperature T_{F} as 0.46TF for 171Yb and 0.54TF for 173Yb. The same scattering lengths for different spin components make this mixture featured with the novel SU(2)×SU(6) symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the SU(2)×SU(6) Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.     

Cartesian Dynamics of Simple Molecules X Linear Quadratomics (C∞v Symmetry)

The vibrations of linear ABC₂ type molecules with C_∞V point group are analysed in terms of Cartesian co-ordinates. Algebraic expressions for the three stretching and two bending normal mode frequencies are derived in terms of longitudinal and transverse force constants, atomic masses and bond lengths. Values of non-valence interaction parameters are transferred from A₂B₂ (D_∞h) molecules, and values of the principal force constants are adjusted to reproduce the observed frequencies for a number of asymmetric halogen derivatives of acetylene. Normal mode frequencies of various isotopic species are also calculated. The nature of the computed eigenvectors for these molecules is briefly discussed. It is found that the carbon-carbon and carbon-hydrogen valence interactions remain approximately constant for these molecules, whereas the carbon-halogen bonds show a weakening trend with increasing halogen mass.     

Nondiagonal radiative (v i v jγ) interactions in an external field

Radiative v_j v_i and v_lv_j transitions of massive Dirac neutrinos are studied in the field of a linearly polarized wave and in a constant crossed field within the framework of an invariant procedure being developed for calculations in plane-wave-type fields. It is shown that with the upper bound used for the anomalous magnetic moment of the neutrinos, consideration of the external field may be decisive in the case of the v_j v_i (m_j>m_i) photodecay, with possible nontrivial consequences in the astrophysical aspect.Moscow State Open Pedagogical Institute. Translated from Izvestiya Vysshikh Zavedenii, Fizika, No. 7, pp. 11–17, July, 1994.     

Relative probabilities of spontaneous transitions in v″ progressions of the G1Σ g + , v′→B 1Σ u + , v″ bands of the H2 molecule

The probabilities of spontaneous transitions in v″ progressions of the G ¹Σ _g ⁺ →B ¹Σ _u ⁺ bands of the H₂ molecule (the 3D→2B electronic transition in notations of G.H. Dieke) are, for the first time, experimentally studied. The line strength ratios were measured for 78 G ¹Σ _g ⁺ , v′, J′→B ¹Σ _u ⁺ , v″, J″ electronic-vibrational-rotational spectral lines having a common upper level but belonging to different bands of v″ progressions (the vibrational branching coefficients). For this purpose, the intensities of lines of the P and R branches, emitted by a low-pressure plasma and corresponding to different values of the rotational (J′=0–11) and vibrational (v′=0–3 and v″=0–7) quantum numbers, were used. It was found that the changes in the vibrational branching coefficients with variation of v′ and v″ are significant (up to a factor of 20). For most bands studied, the dependences of the vibrational branching coefficients on the rotational quantum number J′ of an upper level are rather weak and do not exceed 30%. It was established that the difference between the experimental values of ratios of the vibronic transition probabilities (summed over J″) and the results of calculation in the adiabatic approximation strongly depends on v′, reaching a factor of 25 for a transition from the v′=2 level. At the same time, the discrepancy between the experimental data and the results of nonadiabatic ab initio calculations lies between 1.0 and 2.3.     

Analysis of Bc→τvτ at CEPC

Precise determination of the Bc → tvt branching ratio provides an advantageous opportunity for under-standing the electroweak structure of the Standard Model,me...     

Observation of the v′=8←v=0 vibrational overtone in cold trapped HD+

We report the observation of the hitherto undetected v′=8←v=0 vibrational overtone in trapped HD⁺ molecular ions, sympathetically cooled by laser-cooled Be⁺ ions. The overtone is excited using 782 nm laser radiation, after which HD⁺ ions in v=8 are photodissociated by the 313 nm laser used for Be⁺ cooling. The concomitant loss of HD⁺ is detected by the method of secular excitation (Roth et al. in Phys. Rev. A. 74:040501(R), 2006). We furthermore present details of the experimental setup, and we show that results from spectroscopy of v′=8←v=0 overtones in combination with accurate ab initio calculations may yield a new value for the proton–electron mass ratio with an accuracy of order 1 ppb.     

Towards a constructive approach of a gauge invariant,massiveP(φ)2 theory

As part of a possible constructive approach to a gauge invariantP()₂ theory, we consider massive, scalar, polynomially selfcoupled fields in a fixed external Yang-Mills potentialA in two-dimensional euclidean space. For a large class ofA's we show that the corresponding euclidean Green's functions for the fields have a lower mass gap for weak coupling which is uniform inA. The result is obtained by adapting the Glimm-Jaffe-Spencer cluster expansion to the present situation through Kato's inequality, which reflects the diamagnetic effect of the Yang-Mills potential. A discussion of the corresponding gauge covariance is included.     

Study of scalar meson a0(980) from B→a0(980)π decays

In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B0 →a00(980)π0, a0+(980)π-, a0-(980)π and B- →a00(980)π-, a0-(980)π0 by employing the perturbative QCD (pQCD) factorization approach at the leading order. We found that (a) the pQCD predictions for the branching ratios are around (0.4 - 2.8) × 10-6, consistent with currently available experimental upper limits; (b) the CP asymmetries of B0→ao(980)π0 and B-→a0-(980)π0 decays can be large, about (70-80)% for α = 100°.     

Millimeter-wave spectrum of the C4v molecule IOF5: l-type doubling of the kl = −1 transitions in the v11(E) = 1 state spectrum

Measurements of the rotational spectrum of the C_4v molecule IOF₅ are reported for the excited vibrational state v₁₁(E) = 1 for the transitions J13 ← 12, 14 ← 13, 16 ← 15, and 17 ← 16 (55–72 GHz) including the observation of the kl = −1 (q⁻), l-doubling effect. Detailed assignments of the E-state spectrum are presented based on the overlapping quadrupole structure. These data are analyzed together with earlier results for the excited vibrational state v₆(B₁) = 1 to give information concerning the ν₆(B₁)-ν₁₁(E) Coriolis interaction and the (Δl, Δk) = (2, 2) (q⁺) and (2, −2) (q⁻)l-resonance interactions. It is found that q₁₁⁻ = −2.57(10) MHz, |q₁₁⁺| = 0.094(20) MHz, Δ = ν₆ − ν₁₁ = 45.2(7) cm⁻, ζ_11,11^z = +0.18(1) and |ζ_6,11^y| = 0.73(4).     

The dipole moment function of CO(a 3Π)

The dipole moment function of the a ³Π state of CO is calculated using the multi-configuration self-consistent-field method of Wahl and Das. Only the dominant valence charge-transfer correlation configurations are mixed with the Hartree-Fock configuration since only the region between the classical turning points of the v = 1 vibrational level is considered. The calculated function does not agree with the shape of the fitted dipole moment function of Wicke et al. Configurations chosen on the basis of the model of optimized valence configurations do not determine an accurate dipole moment function for an open shell system.