The radiative characteristics of the rovibronic states of the hydrogen molecule: IV. Relative probabilities of the r 3Π g ? , s 3Δ g ? → c 3Π u ± spontaneous transitions of the H2 molecule

A statistical analysis of the available literature data and data obtained in this work on the wave numbers of the lines that appear in triplet-triplet rovibronic transitions of the H₂ molecule was performed. This allowed us to verify and refine the controversial identification of spectral lines and find the optimum rovibronic level energy values for the c ³Π _u ^±, r ³Π _g ⁻, and s ³Δ _g ⁻ states. The ratios between the line strengths of the P, Q, and R branches of the (4dπ)r ³Π _g ⁻, (4dδ)s ³Δ _g ⁻ → (2pπ)c ³Π _u ^± band systems of the H₂ molecule were measured systematically. The calculation results obtained in the Frank-Condon approximation differed substantially (by up to two orders of magnitude) from the experimental data. The dependences of the ratios between rovibronic line strengths of the r ³Π _g ⁻ → c ³Π _u ^± and s ³Δ _g ⁻ → c ³Π _u ^± transitions on the rotational quantum number N′ of the upper level were found to correlate with each other. The deviations of adiabatic theory increase as N′ grows, which is evidence of an important role played by electronic-rotational interactions in the perturbation of transition probabilities. The experimental ratios between the probabilities of rovibronic transitions satisfactorily agree with the results of calculations within the framework of the simple nonadiabatic model taking into account electronic-rotational interaction of radiating adiabatic states in the approximation of pure precession. The dependences of transition probabilities on N′ were obtained for the first time for the first four diagonal bands of the r ³Π _g ⁻, s ³Δ _g ⁻ → c ³Π _u ^± transitions. Original Russian Text ? S.A. Astashkevich, B.P. Lavrov, A.V. Modin, I.S. Umrikhin, 2008, published in Khimicheskaya Fizika, 2008, Vol. 27, No. 2, pp. 22–38.     

Indication of asymptotic scaling in the reactions dd → p3H, dd → n3He, and pd → pd

It is shown that the differential cross sections of the reactions dd → n ³He and dd → p ³H measured at a c.m.s. scattering angle θ_cm = 60° in the interval of the deuteron beam energy 0.5–1.2 GeV demonstrate the scaling behavior dσ/dt ∼ s ⁻²², which follows from constituent quark counting rules. It is found also that the differential cross section of the elastic dp → dp scattering at θ_cm = 125°–135° follows the scaling regime ∼s ⁻¹⁶ at beam energies 0.5–5 GeV. These data are parameterized here using the Reggeon exchange. From Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, Vol. 81, No. 7, 2005, pp. 387–390. Original English Text Copyright ? 2005 by Uzikov. This article was submitted by the author in English.     

Solvatochromic shift of the 0-0 phosphorescence band and change of polarizability in the a 1δg → X 3Σ g? -transition in the oxygen molecule

We used known experimental data to analyze the influence of intermolecular interactions on the position of the 0-0-band a¹Δ_g → X³Σ _g ⁻ phosphorescence of molecular oxygen in solutions. A bathochromic (red) shift caused by dispersion interactions and fluctuations of the internal electric field (induction effect) is analyzed employing new formulas obtained by us in the framework of the Onsager model. The contributions from intermolecular repulsion and higher multipole interactions to the shift of the spectrum are also discussed. It is found that the polarizability in the a¹Δ_g state is higher than in the X³Σ _g ^t- state by 0.19 ± 0.03 ų. Taking into account the induced nature of O₂ phosphorescence in solutions, it is noted that the change of polarizability Δα_eg = 0.19 ų should differ from the change of Δα_eg inherent in free molecular oxygen. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 4, pp. 453–459, July–August, 2007.     

Improved absolute frequency measurement of the 115In+ 5s2 1S0-5s5p3P0 narrowline transition: Progress towards an optical frequency standard

We report on an improved absolute frequency measurement of the 5s ^{2 1} S ₀0-5s5p ³ P ₀ narrowline clock transition at 236.5 nm, for a single, trapped, and laser-cooled ¹¹⁵In ion. Using a narrowline laser as the local oscillator, a linewidth of 43 Hz for the transition is resolved. The uncertainty of the transition frequency’s centroid is 18 Hz, leading to a fractional uncertainty of 1.4 × 10⁻¹⁴. For absolute frequency measurement, we use an optical frequency comb locked to a cesium clock as the reference. The transition frequency is found to be 1267402452900967(63) Hz, averaged over 13 days of separate measurements. The accuracy is about 5.0 × 10⁻¹⁴. We discuss possibilities for further improvement. Original Text ? Astro, Ltd., 2007.     

Search for direct CP violating charge asymmetries in K±→π±π+π- and K±→π±π0π0 decays

A measurement of the direct CP violating charge asymmetries of the Dalitz plot linear slopes A_g=(g⁺-g^-)/(g⁺+g^-) in K^±→π^±π⁺π^- and K^±→π^±π⁰π⁰ decays by the NA48/2 experiment at CERN SPS is presented. A new technique of asymmetry measurement involving simultaneous K⁺ and K^- beams and a large data sample collected allowed a result of an unprecedented precision. The charge asymmetries were measured to be A^c _g=(-1.5±2.2)×10^-4 with 3.11×10⁹K^±→π^±π⁺π^- decays, and Aⁿ _g=(1.8±1.8)×10^-4 with 9.13×10⁷K^±→π^±π⁰π⁰ decays. The precision of the results is limited mainly by the size of the data sample.     

Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)

The spin polarized β-emitting nuclei¹²B (I ^π=1⁺,T _1/2=20.18 ms) were produced by the nuclear reaction¹¹B(d, p)¹²B and by the selection technique of the incident deuteron energy and the¹²B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei¹²B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment of¹²B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift.     

Excitation cross sections of thulium atom transitions terminating at 4f13(2Fo)6s6p(3Po (7/2, J2) levels with J2 = 0, 1

The excitation of odd levels of the thulium atom, spontaneous transitions from which terminate at the 4f ¹³(² F ^o)6s6p(³ P ^o) (7/2, J ₂) levels with J ₂ = 0, 1, is studied by the method of extended crossing beams. Fifty four excitation cross sections are measured at an excitation electron energy of 50 eV. Seven optical excitation functions are recorded in the electron energy range of 0–200 eV.     

Search for T violation in the decays K+ → π0μ+ν and K+ → μ+νγ

Recent advances in a search for a T-violating transverse muon polarization in the decays K ⁺ → π ⁰ μ ⁺ ν and K ⁺ → μ ⁺ νγ in the on-going E246 experiment at KEK are reported. Future prospects in polarization measurements are also discussed. From Yadernaya Fizika, Vol. 65, No. 2, 2002, pp. 269–273. Original English Text Copyright ? 2002 by Kudenko. This article was submitted by the author in English.     

On CP-odd effects in KL → 2π and K± → π±π±π± decays generated by direct CP violation

The amplitudes of the K ^± → 3π and K→ 2π decays are expressed in terms of different combinations of one and the same set of CP-conserving and CP-odd parameters. Extracting the magnitudes of these parameters from the data on K → 2π decays, we estimate an expected CP-odd difference between the values of the slope parameters g ⁺ and g ⁻ of the energy distributions of “odd” pions in K ⁺ → π⁺π⁺π⁻ and K ⁻ → π⁻π⁻π⁺ decays. From Yadernaya Fizika, Vol. 68, No. 1, 2005, pp. 89–94. Original English Text Copyright ? 2005 by Shabalin. This article was submitted by the author in English.     

Relations at order p6 in chiral perturbation theory

We report on a search of relations valid at order p ⁶ in Chiral Perturbation Theory. We have found relations between π π, π K scattering, K _ℓ4 decays, masses and decay constants and scalar and vector formfactors. In this paper we give the relations and a first numerical check of them.     

Postcollision interaction upon electron excitation of 4sns1S0, 3S1 and 4snd1D2, 3DJ levels of zinc atom

The optical excitation functions (OEFs) for four series of spectral lines of the Zn atom at the transitions 4sn ₁ s ¹ S ₀ → 4s4p ¹ P ₁^∘ (n ₁ = 6–10), 4sn ₂ s ³ S ₁ → 4s4p ³ P ₂^∘ (n ₂ = 6−8), 4sn ₃ d ¹ D ₂ → 4s4p ¹ P ₁^∘ (n ₃ = 4−6), 4sn ₄ d ³ D _{1, 2, 3} → 4s4p ³ P ₂^∘ (n ₄ = 4−7) excited by a monoenergetic (0.04–0.08 eV) electron beam with energies from the excitation threshold to 18–19 eV are measured. In the energy dependences of the excitation cross sections, the effect of post-collision interaction of slow (scattered) and fast (emitted after the autoionization state decay) electrons is observed and described. This interaction leads to the capture of a slow electron into the listed discrete levels and the appearance of maxima in the excitation functions. The energies of the maxima are used to determine the energies and widths of single autoionization states or their groups by approximate formulas of the classical approach. The autoionization levels of the zinc atom responsible for the maxima observed are determined. Possible transfer of the orbital angular momentum between electrons is analyzed.     

K0πand K*0Σ+ photoproduction off the proton

The exclusive reactions γp → K ^*0Σ⁺(1189) and γp → K ⁰π⁰Σ⁺(1189) , leading to the p 4π⁰ final state, have been measured with a tagged photon beam for incident energies from threshold up to 2.5GeV. The experiment has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were combined to a photon detector system of almost 4π geometrical acceptance. Differential and total cross-sections are reported. At energies close to the threshold, a flat angular distribution has been observed for the reaction γp → K ⁰π⁰Σ⁺ suggesting dominant s -channel production. Σ^*(1385) and higher-lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions of the reaction γp → K ^*0Σ⁺ indicates a t -channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical predictions.     

EPR of Fe3+ ion and symmetry of [AIF5·H2O]2? complex ion in (NH4)2AIF5·H2O single crystals

We used the spin-Hamiltonian method for the analysis of the electron paramagnetic resonance (EPR) spectrum of Fe³⁺ as a probe ion in (NH₄)₂AlF₅·H₂O single crystalline basic material. The theoretical expressions for the magnetic field (at which the fine structure transition lines appear) versus the angle between the magnetic field and the axis of symmetry of the magnetic complex are also given. These values were calculated by applying the perturbation theory to the second-order terms. From the experimental results (at 300 K and 9.21 GHz), the spin-Hamiltonian parameters were deduced:D=(668±10)·10⁻⁴ T,E=(−56±10)·10⁻⁴ T,a=(−54±10)·10⁻⁴ T,F=(30±10)·10⁻⁴ T. An isotropic superhyperfine structure was evidenced for the five fluorine ions. The obtained EPR data were used to determine the local symmetry of the Al³⁺ ion. A good agreement with X-ray diffraction measurements was found.     

Improved measurement of theB0 andB+ meson lifetimes

The lifetimes of theB ⁰ andB ⁺ mesons have been measured with theAleph detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991–1994. In the first of three methods, semileptonic decays ofB ⁰ andB ⁺ mesons were partially reconstructed by identifying events containing a lepton with an associatedD*⁻ or meson. The second method used fully reconstructedB ⁰ andB ⁺ mesons. The third method, used to measure theB ⁰ lifetime, employed a partial reconstruction technique to identifyB ⁰→D*⁻ π ⁺ X decays.     

Production of the f0(980) resonance in the reaction π?p → π0π0n

Predictions of the model that relies on purely one-pion exchange and which describes well GAMS data on the rearrangement of the S-wave mass spectrum of the π ⁰ π ⁰ system in the region of the f ₀(980) resonance with increasing −t in the reaction π ⁻ p → π ⁰ π ⁰ n are compared with detailed data that were recently obtained at the Brookhaven National Laboratory (BNL) for the m and t distributions of the number of events of the reaction π ⁻ p → π ⁰ π ⁰ n. An analysis revealed that these BNL data disagree with the predictions of this model. This suggests that a different mechanism must be responsible for the phenomenon discovered experimentally. Most likely, this is the a ₁-exchange mechanism. __________ Translated from Yadernaya Fizika, Vol. 66, No. 2, 2003, pp. 381–387. Original Russian Text Copyright ? 2003 by Achasov, Shestakov.     

Calculation of O(p6) corrections to the muon transverse polarization in Kl2γ decay

The contribution of final-state interactions to the muon transverse polarization in the decay K ⁺ → μ⁺ v γ is calculated within chiral perturbation theory to O(p ⁶) terms. It is shown that the O(p ⁶) corrections to the transverse polarization are much smaller than the O(p ⁴) leading contribution. Original Russian Text ? V.V. Braguta, A.A. Likhoded, A.E. Chalov, 2007, published in Yadernaya Fizika, 2007, Vol. 70, No. 2, pp. 386–391.     

Quark momentum-space charge distribution in deuteron and neutron/proton structure functions ratio

The electromagnetic polarizabilities of the nucleon are shown to be essentially composed of the nonresonant α _p(E ₀₊) = + 3.2, α _n(E ₀₊) = + 4.1, the t-channel α ^t _{p, n} = - β ^t _{p, n} = + 7.6 and the resonant β _{p, n}(P ₃₃(1232)) = + 8.3 contributions (in units of 10^-4fm^3). The remaining deviations from the experimental data Δα _p = 1.2±0.6, Δβ _p = 1.2±0.6, Δα _n = 0.8±1.7 and Δβ _n = 2.0±1.8 are contributed by a larger number of resonant and nonresonant processes with cancellations between the contributions. This result confirms that dominant contributions to the electric and magnetic polarizabilities may be represented in terms of two-photon coupling to the σ-meson having the predicted mass m _σ = 666MeV and two-photon width Γ _γγ = 2.6keV.     

Spin-other-orbit interaction in highly excited configurations with p and g electrons in outer shells

The matrix of the operator of the spin-other-orbit interaction energy is constructed for npn’g and np ⁵ n’g configurations. The matrix elements of this operator are calculated in the single-configuration approximation with wave functions in the LSJM representation and in the representation of uncoupled angular momenta using the known general formulas. The spin-other-orbit interaction is represented by three direct and three exchange radial Marvin spin interaction integrals.