{^6_{\Lambda} \rm{H}} Modeled as {^4_{\Lambda} \rm{H}} + n + n

A three-body calculation for the \({^4_{\Lambda} \rm{He}}\) and \({^6_{\Lambda}{\rm H}}\) hypernuclei has been undertaken. The respective cores are \({^4_{\Lambda}{\rm H}}\) . The interactions in the \({^6_{\Lambda}{\rm He}}\) system, modeled as \({^4_{\Lambda} {\rm H+p+n}}\) , are reasonably well known. For example, the p n interaction is well determined by the p n scattering data, the \({^4_{\Lambda}{\rm H}}\) –p interaction can be fitted to the \({^5_{\Lambda}{\rm He}}\) binding energy. The \({^4_{\Lambda}{\rm He}}\) –n interaction can be fitted to α–n scattering data. For the ⁴He–n system the s-wave can be modeled alternatively as a repulsive potential or as an attractive potential with a forbidden bound state. We explore these alternatives in ⁶He, because the interaction comes into play in modeling \({^6_{\Lambda}{\rm He}}\) as well as in our \({^4_{\Lambda}{\rm H}}\) + n + n model of \({^6_{\Lambda}{\rm H}}\) , where the valence neutrons are Pauli blocked from the s-shell of the core nucleus.     

Stability of {\text{SrCe}}_{{0.9}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} and {\text{SrZr}}_{{0.2}} {\text{Ce}}_{{0.7}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} under H2 atmospheres

Previous H₂ permeation tests showed a degradation of H₂ permeation flux with time. To understand the cause of degradation and develop a solution, the stability of $ {\text{SrCe}}_{{0.9}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ and $ {\text{SrZr}}_{{0.2}} {\text{Ce}}_{{0.7}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ samples were studied under dry and wet H₂ atmospheres. Total conductivity of $ {\text{SrCe}}_{{0.9}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ increased with time in dry H₂. The X-ray diffraction pattern of $ {\text{SrCe}}_{{0.9}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ after dry hydrogen atmosphere heat treatments show CeO₂ peaks indicating that $ {\text{SrCe}}_{{0.9}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ decomposes under dry H₂ atmospheres; scanning electron microscopy and energy dispersive X-ray spectroscopy analyses prove that decomposition proceeded along the grain boundaries. $ {\text{SrZr}}_{{0.2}} {\text{Ce}}_{{0.7}} {\text{Eu}}_{{0.1}} {\text{O}}_{{3 - \delta }} $ was investigated and demonstrated greater stability under dry hydrogen atmospheres. However, Zr substitution results in a tradeoff with electrical properties.     

Model-independent analysis of Higgs spin and CP properties in the process \boldsymbol{e}^{+} \boldsymbol{e}^{-} \to\boldsymbol{t}\bar{\boldsymbol{t}} \boldsymbol{\Phi}

In this paper we investigate methods to study the $t\bar{t}$ Higgs coupling. The spin and CP properties of a Higgs boson are analysed in a model-independent way in its associated production with a $t\bar{t}$ pair in high-energy e ⁺ e ^? collisions. We study the prospects of establishing the CP quantum numbers of the Higgs boson in the CP-conserving case as well as those of determining the CP-mixing if CP is violated. We explore in this analysis the combined use of the total cross section and its energy dependence, the polarisation asymmetry of the top quark and the up-down asymmetry of the antitop with respect to the top–electron plane. We find that combining all three observables remarkably reduces the error on the determination of the CP properties of the Higgs Yukawa coupling. Furthermore, the top polarisation asymmetry and the ratio of cross sections at different collider energies are shown to be sensitive to the spin of the particle produced in association with the top-quark pair.     

Measurement of the {\rm\bf B_{\bf d}^{\bf 0}- {\bf \bar{B}}_{\bf d}^{\bf 0}} oscillation frequency

Time-dependent mixing is studied using about two million hadronic Z decays registered by L3 in 1994 and 1995. For this study three techniques are used. Tagging of the b-quark charge at decay time is performed by identifying leptons from semileptonic B decays. The flavour of the b quark at production time is determined from the charge of the lepton in the opposite hemisphere or by using a jet-charge technique. The proper time of the B-particle decay is obtained by reconstructing the production and decay vertices or by a measurement of the lepton impact parameter. The combined result for the frequency of meson oscillations is Received: 20 February 1998 / Revised version: 23 March 1998 / Published online: 12 August 1998     

Lasing of optically pumped XeF and analysis of the spectrum of the laser transitionB^2 \sum _{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}^ + - X^2 \sum _{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}}^ +

The operating principle of a photodissociation XeF laser (λ?350 nm) is discussed. A laser operating on the gas mixture XeF₂:N₂(SF₆):Ar pumped by radiation from an open high-current discharge is described. The maximum lasing duration is 5 μsec, the maximum output energy is 0.15 J. The vibrational structure of the XeF-molecule transition B²Σ_1/2 ⁺ ? X²Σ_1/2 ⁺, observed in absorption, luminescence, and stimulated emission, is investlgated. The vibrational quantum and the anharmonicity in the upper and lower states are measured: ω_e ^' = 308.7 cm^-1, ω_e ^'x_e ^' = 1.44 cm^-1, ω_e ^'' = 225.7 cm^-1, ω_e ^''x_e ^'' = 11.0 cm^-1. The difference between the equilibrium internuclear distances of the XeF molecule is determined for the excited (B) and ground (X) states, namely r_e ^' - r_e ^'' = 0.33 +- 0.01 Å.     

Investigation of atmospheric {\text{O}}_{2}{\text{X}}{^{ 3}}{ \sum_{\text{g}}^{ - }} \,{\text{to}}\, {\text{b}}{^{ 1}}{ \sum_{\text{g}}^{ + }} using open-path tunable diode laser absorption spectroscopy

A tunable diode laser absorption spectroscopy (TDLAS) device fiber coupled to a pair of 12.5 in. telescopes was used to study atmospheric propagation for open path lengths of 100–1,000 meters. More than 50 rotational lines in the molecular oxygen A-band O₂ $ {\text{X}}{^{ 3}}{ \sum_{\text{g}}^{ - }} \,{\text{to}}\, {\text{b}}{^{ 1}}{ \sum_{\text{g}}^{ + }} $ transition near 760 nm were observed. Temperatures were determined from the Boltzmann rotational distribution to within 1.3 % (less than ±2 K). Oxygen concentration was obtained from the integrated spectral area of the absorption features to within 1.6 % (less than ±0.04 × 10¹⁸ molecules/cm³). Pressure was determined independently from the pressure-broadened Voigt lineshapes to within 10 %. A fourier transform interferometer (FTIR) was also used to observe the absorption spectra at 1 cm^?1 resolution. The TDLAS approach achieves a minimum observable absorbance of 0.2 %, whereas the FTIR instrument is almost 20 times less sensitive. Applications include atmospheric characterization for high energy laser propagation and validation of monocular passive raging.     

Study of Inelastic $$\boldsymbol{A}$$ ( $$\boldsymbol{p,p^{\prime}}$$ ) $$\boldsymbol{X}$$ Reaction with $${}^{\mathbf{9}}$$ Be and $${}^{\mathbf{90}}$$ Zr Nuclei at 1 GeV

Physics of Atomic Nuclei - The secondary proton polarization and differential cross sections of the ( $$p,p^{\prime}$$ ) inelastic reaction on nuclei $${}^{9}$$ Be and $${}^{90}$$ Zr at the initial...     

Properties of $$\boldsymbol{B}_{\boldsymbol{c}}$$ Mesons and Variational Constraints on Their Masses

Physics of Atomic Nuclei - Spectrum, radii, radial wave functions at origin, decay constants, and momentum widths for radial and orbital excited $$B_{c}$$ mesons are derived within non-relativistic...     

Differential $$\boldsymbol{W}^{{+}}{/}\boldsymbol{W}^{{-}}$$ Cross Section Ratios for $$\boldsymbol{W}$$ Plus Jet Production in $$\boldsymbol{pp}$$ Collisions Through (N)NLO in QCD

Physics of Atomic Nuclei - This paper presents a phenomenological study of differential $$W^{+}/W^{-}$$ cross section ratios for $$W$$ -boson production in association with a jet through...     

Study of semileptonic decay of ${\bar{B}}_{s}^{0} \rightarrow \phi {l}^{+}{l}^{-}$ in QCD sum rule

In this work we study the semileptonic decay of ${\bar{B}}_{s}^{0}\to \phi {l}^{+}{l}^{-}$ (l=e, μ, τ) with the QCD sum rule method. We calculate the ${\bar{B}}_{s}^{0}\to \phi $ translation form factors relevant to this semileptonic decay, then the branching ratios of ${\bar{B}}_{s}^{0}\to \phi {l}^{+}{l}^{-}$ (l=e, μ, τ) decays are calculated with the form factors obtained here. Our result for the branching ratio of ${\bar{B}}_{s}^{0}\to \phi {\mu }^{+}{\mu }^{-}$ agree very well with the recent experimental data. For the unmeasured decay modes such as ${\bar{B}}_{s}^{0}\to \phi {e}^{+}{e}^{-}$ and ${\bar{B}}_{s}^{0}\to \phi {\tau }^{+}{\tau }^{-}$, we give theoretical predictions.     

Analysis of Angular $$\boldsymbol{t{-}\gamma}$$ Correlations in the Reaction $${}^{\boldsymbol{27}}$$ Al $$\boldsymbol{(\alpha,t)^{28}}$$ Si(2 $${}^{\boldsymbol{+}}$$ )

Physics of Atomic Nuclei - Angular $$t$$ – $$\gamma$$ correlations measured earlier in the reaction $${}^{27}$$ Al $$(\alpha,t)^{28}$$ Si(2 $${}^{+}$$ ) occurring at $$E_{\alpha}=30.3$$ MeV...     

The Semileptonic Decay Modes {\bar{B} \rightarrow D\ell \bar{\nu}} and {\bar{B}_{s} \rightarrow D_{s} \ell \bar{\nu}}: A New Analysis in Potential Model

We consider the Schrödinger equation with a combination of Deng–Fan-type and harmonic terms. To solve the corresponding differential equation, we split the equation to two parts: the parent and the perturbation terms. We use the Nikiforov–Uvarov technique to solve the parent part. For the perturbation part, we apply the series expansion method. Next, using the calculated wave function, we investigate some bottom and charm mesons within the Isgur–Wise function formalism. We present especially semileptonic \({\bar{B} \rightarrow D\ell \bar{\nu}}\) and \({\bar{B}_{s} \rightarrow D_s \ell \bar{\nu }}\) decay widths, branching ratios and \({|V_{cb}|}\) (element of the CKM matrix). Masses of some pseudoscalar mesons are also indicated. Comparisons of our results with experimental values and other approaches are included.     

Measurement of the Cross Section for the Process $${e^{+}e^{-}}{\to}{\omega\pi}^{{0}}{\to}{\pi}^{{+}}{\pi}^{{-}}{\pi}^{{0}}{\pi}^{{0}}$$ with the SND Detector

Physics of Atomic Nuclei - The process $$e^{+}e^{-}\to\omega\pi^{0}\to\pi^{+}\pi^{-}\pi^{0}\pi^{0}$$ was studied in the energy range between 1 and 2 GeV to the best precision in the world. The data...