Molecular three-body approach to Λ9Be and Σ9Be hypernuclei

The dependence of the low-lying spectra of ${}_{\mathrm{\Lambda ,\; \Sigma }}{}^9\text{Be}$ hypernuclei on hyperon-α interaction in the molecular α + α + Λ(Σ) scheme has been studied. A suggestion is made for obtaining the strengths of both p-wave and spin-orbit Λ-α interactions from the experimental ${}_{\mathrm{\Lambda }}{}^9\text{Be}$ spectrum. A relation between the Σ⁰-binding energies $\text{B}{}_{\mathrm{\Sigma }}\text{(}{}_{\mathrm{\Sigma }}{}^9\text{Be}\text{)}$ and $\text{B}{}_{\mathrm{\Sigma }}\text{(}{}_{\mathrm{\Sigma }}{}^9\text{He}\text{)}$ has been established and on its basis a prediction is made about a possible binding energy of ${}_{\mathrm{\Sigma }}{}^5\text{He}$.     

Multilevel description of the Rh isotopes in the interacting boson-fermion model

We present a multilevel calculation within the framework of the interacting boson-fermion model (IBFM-1) of the odd-mass ^101–109Rh isotopes. We calculate both positive- and negative-parity states of the same hamiltonian, starting from the $\text{1g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$, $\text{2p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, $\text{2p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$, $\text{lf}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ and $\text{2d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ single-particle orbitals. We discuss energy spectra, electromagnetic E2 transition rates and one-nucleon transfer properties. We also discuss the influence of the $\text{1f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ orbital on the one-nucleon transfer properties. The results of the calculation for the negative-parity states are compared with the results of the $\text{U(}\text{6}\text{12}$) supersymmetry scheme of the interacting boson model.     

Prognosis for urban noise in the United States—The present to 1990

A forecast of $\text{L}{}_{\mathrm{dn}}$ changes within the residential areas of constant population density is made in terms of external noise levels ($\text{L}{}_1\text{L}{}_2$) and ‘vehicle travels’ ($\text{N}{}_1\text{N}{}_2$) for cars, trucks and buses. Anticipated increases of $\text{N}{}_1$ and $\text{N}{}_2$ have been estimated by the use of trend line analysis (Figs. 3 and 4). A few hypotheses of $\text{L}{}_1$ and $\text{L}{}_2$ decrease have been considered. Increase of $\text{L}{}_{\mathrm{dn}}$ by more than 3 dB may be expected until 1993.     

Renormalization group improved predictions for quarkonium decay

A method recently suggested to resolve the ambiguity related to scheme dependence in perturbative QCD is applied to calculations of radiative corrections to quarkonium decay. Renormalization group improved predictions are given for the ratio $\text{R=Г(}{}^1\text{S}{}_0\text{→had)/Г(}{}^3\text{S}{}_1\text{→had)}$, as a function of $\text{λ}{}_{\mathrm{<mtext>MS</mtext>}}$. The values obtained are substantially larger than in conventional schemes. One finds in particular that R>182 for charmonium, and R>174 for bottomium, independently of the value of the quark mass and $\text{λ}{}_{\mathrm{<mtext>MS</mtext>}}$. It follows that $\text{Г(}\text{n}{}_{\mathrm{c}}\text{→}\text{had}\text{)>6.9}\text{MeV}$ and $\text{Г(}\text{n}{}_{\mathrm{b}}\text{→}\text{had}\text{)>3.6}\text{MeV}$. Values of the wave function at the origin as a function of $\text{λ}{}_{\mathrm{<mtext>MS</mtext>}}$ are also extracted from the measured gluonic width of the ³S₁ state. An upper bound for $\text{λ}{}_{\mathrm{<mtext>MS</mtext>}}$ is obtained under some assumptions.     

Combination tones in the response of single degree of freedom systems with quadratic and cubic non-linearities

The method of multiple scales is used to analyze the response of a single-degree-of-freedom system to either the combination resonance of the additive type $\text{Ω}{}_2\text{+ Ω}{}_1\text{≈ ω}{}_0$ or the combination resonance of the difference type $\text{Ω}{}_2\text{? Ω}{}_1\text{≈ ω}{}_0$, where $\text{Ω}{}_1$ and $\text{Ω}{}_2$ are the frequencies of the excitation and ω₀ is the linear undamped natural frequency of the system. To the second approximation, the combination resonance of the additive type has three effects on the steady state response. First, it produces terms having the frequencies $\text{Ω}{}_1\text{, Ω}{}_2$ and $\text{Ω}{}_2\text{+ Ω}{}_1$ at first order and terms having the frequencies 0, $\text{2Ω}{}_1\text{, 2Ω}{}_2\text{, Ω}{}_2\text{? Ω}{}_1$, $\text{2(Ω}{}_2\text{+ Ω}{}_1\text{), Ω}{}_2\text{+ 2Ω}{}_1$ and $\text{2Ω}{}_2\text{+ Ω}{}_1$ at second order. Second, it produces a shift in the natural frequency of the system. Third, it produces a virtual primary-resonant excitation having the frequency $\text{Ω}{}_2\text{+ Ω}{}_1\text{≈ ω}{}_0$ that makes the component having the frequency $\text{Ω}{}_2\text{+ Ω}{}_1$ be of first rather than second order. Similar effects are produced by a combination resonance of the difference type or a superharmonic resonance of order two.     

Stark effect in the torsio-rotational spectrum of propargyl mercaptan and SH bond moment determination

The Stark effect of rotational and torsio-rotational transitions of propargyl mercaptan has been analyzed. Assuming a dependence of the dipole moment components on the internal rotation angle of the type: $\text{μ}{}_{\mathrm{a}}\text{= μ}{}_{\mathrm{a}}{}^0\text{+ μ}{}_{\mathrm{a}}{}^{\mathrm{(1)}}\text{cos}\text{α}$, $\text{μ}{}_{\mathrm{b}}\text{= μ}{}_{\mathrm{b}}{}^0\text{+ μ}{}_{\mathrm{b}}{}^{\mathrm{(1)}}\text{cos}\text{α}$, and $\text{μ}{}_{\mathrm{c}}\text{= μ}{}_{\mathrm{c}}{}^{\mathrm{(1)}}\text{sin}\text{α}$, the following values of the determinable quantities were obtained: $\text{μ}{}_{\mathrm{a}}{}^{\mathrm{<mtext>eff</mtext>}}\text{= 0.718 ± 0.003}\text{D}$, $\text{μ}{}_{\mathrm{b}}{}^{\mathrm{<mtext>eff</mtext>}}\text{= 0.495 ± 0.010}\text{D}$, and $\text{μ}{}_{\mathrm{c}}{}^{\mathrm{(1)}}\text{= 0.809 ± 0.015}\text{D}$.The SH bond moment was also evaluated from $\text{μ}{}_{\mathrm{c}}{}^{\mathrm{(1)}}$ and compared with the SH bond moment of similar molecules.     

Asymptotic power laws for hadron calorimeter experiments

This is a study of asymptotic QCD predictions for collisions in which a finite fraction of the available energy is carried by hadrons into an angular region $\text{Ω}$ whose complement is $\text{Ω}{}_{\mathrm{<mtext>a</mtext>}}$ or $\text{Ω}{}_{\mathrm{<mtext>b</mtext>}}$ or $\text{Ω}{}_{\mathrm{<mtext>a</mtext>}}\text{UΩ}{}_{\mathrm{<mtext>b</mtext>}}\text{, Ω}{}_{\mathrm{<mtext>a</mtext>}}$ being fixed cones about the directions of motion of the initial particles. Apart from slow (logarithmic) corrections the asymptotic power laws derived from the covariant parton model appear to be justified provided certain conditions on $\text{Ω}{}_{\mathrm{<mtext>a</mtext>}}$ and/or $\text{Ω}{}_{\mathrm{<mtext>b</mtext>}}$ and the energy deposited in them are met.     

Spectroscopic information on ground-state Ar2, Kr2, and Xe2 from interatomic potentials

Calculations of vibrational and rotational level spacings of homonuclear inert gas diatomic molecules by numerical integration of the radial Schrödinger equation are presented. The potentials which were used for the ground states of Ar₂, Kr₂, and Xe₂ were obtained from accurate fits to the molecular beam scattering data. From the calculated $\text{Δ}\text{G}{}_{\mathrm{<mtext>v+</mtext><mtext>1</mtext><mtext>2</mtext>}}\text{'}\text{s}$ and B_v's, the following spectroscopic constants (in cm^?1) were fitted: for Ar₂ω_e = 31.92, ω_ex_e = 3.31, ω_ey_e = 0.11, B_e = 0.060, α_e = 0.004; for $\text{Kr}{}_2\text{ω}{}_{\mathrm{e}}\text{? 23.99}$, $\text{ω}{}_{\mathrm{e}}\text{x}{}_{\mathrm{e}}\text{? 1.30}$, $\text{ω}{}_{\mathrm{e}}\text{y}{}_{\mathrm{e}}\text{? 0.021}$, $\text{B}{}_{\mathrm{e}}\text{? 0.024}$, $\text{α}{}_{\mathrm{e}}\text{? 0.001}$; for $\text{Xe}{}_2\text{ω}{}_{\mathrm{e}}\text{? 21.26}$, $\text{ω}{}_{\mathrm{e}}\text{x}{}_{\mathrm{e}}\text{? 0.75}$, $\text{ω}{}_{\mathrm{e}}\text{y}{}_{\mathrm{e}}\text{? 0.008}$, $\text{B}{}_{\mathrm{e}}\text{? 0.013}$, $\text{α}{}_{\mathrm{e}}\text{? 0.0004}$.     

Limits on neutrino-antineutrino transitions from a study of high-energy neutrino interactions

We distinguish electron and positron tracks from ν_e and $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ charged-current interactions in a large bubble chamber f ed with a neon-hydrogen mixture. No evidence is seen for an excess of $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ interactions from primary $\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ sources secondary $\text{ν}{}_{\mathrm{\mu }}\text{→}\text{ν}{}_{\mathrm{<mtext>e</mtext>}}\text{or}$$\text{ν}{}_{\mathrm{<mtext>e</mtext>}}\text{→}\text{ν}{}_{\mathrm{<mtext>e</mtext>}}$ oscillations. Upper limits on oscillation parameters, majoron sion and lepton-number violating π and K decays are presented.     

Electron-muon mass ratio,neutrino masses and Weinberg angle in an approximate SU(4)+ ⊗ SU(4)− symmetry for leptons

Assuming an SU(4) group for leptons together with the dynamical equation $\text{P}{}_{\mathrm{z}}\text{{z ? z} = 0}$ ($\text{P}{}_{\mathrm{z}}$ is the projection of the representation z from the direct product z ? z) for the symmetry breaking, we predict: and a Weinberg angle $\text{sin}{}^2\text{θ}{}_{\mathrm{<mtext>w</mtext>}}\text{=}\text{1}\text{4}$.     

The effective T = 1 two-particle matrix elements in the fp shell

The ⁴¹Ca($\text{d}$, p)⁴²Ca reaction has been used to locate the strength distributions for $\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ transfer in ⁴²Ca. Effective $\text{(}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^2$, $\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and ${}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ two-body matrix elements are derived from the data and compared to theoretical predictions.     

Level structure of 48Sc from the 48Ca(p,nγ) reaction

Levels of ⁴⁸Sc up to 3.33 MeV excitation were studied by the reaction ⁴⁸Ca(p,nγ)⁴⁸Sc employing a variety of experimental techniques. A level scheme of ⁴⁸Sc comprising 29 excited states and 54 transitions were determined from the measurements of γ-γ coincidences and γ-ray excitation functions. Within the framework of the statistical compound nucleus model spins and parities of the ⁴⁸Sc levels were assigned from the angular distributions and linear polarizations of the de-excitation γ-rays as well as the excitation functions of the residual levels. From the present experimental results and other available data we tentatively identified some of the levels of the ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9$, $\text{1}\text{d}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}\text{)}$, ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^9\text{, 2}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$), ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$) and ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^7\text{, 1}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$) configurations in addition to the well-known ($\text{π}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{, v}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}{}^{\mathrm{?1}}$) multiplet.     

Hyperfine structure of CH3OH

Hyperfine structure of the (0, 0, 1) - (1, 0, 1) transition of methanol has been investigated by beam absorption and of the (J, 1, 3?) → (J, 1, 3+) transitions for J = 2, 3, and 6 by beam-maser spectroscopy. The best-fit results for the spin-rotation and spin-spin coupling constants $\text{C}{}_{\mathrm{JK\tau \pm }}{}^{\mathrm{(i)}}$ and $\text{D}{}_{\mathrm{JK\tau \pm }}{}^{\mathrm{(i)}}$, respectively, are in kHz¹: $\text{C}{}_{101}{}^{\mathrm{(1)}}\text{= 2.4(10)}$, $\text{C}{}_{101}{}^{\mathrm{(2)}}\text{= ?0.6(10)}$, $\text{D}{}_{101}{}^{\mathrm{(1)}}\text{= ?13.8(9)}$, $\text{D}{}_{101}{}^{\mathrm{(2)}}\text{= 7.0(9)}$, $\text{C}{}_{\mathrm{213?}}{}^{\mathrm{(1)}}\text{= ?5.0(10)}$, $\text{C}{}_{\mathrm{213?}}{}^{\mathrm{(2)}}\text{= ?5.5(10)}$ and ($\text{C}{}_{\mathrm{J13?}}{}^{\mathrm{(2)}}\text{- C}{}_{\mathrm{J13+}}{}^{\mathrm{(2)}}\text{) = 0.98(9)}$.     

Evidence for Mn clustering in dilute CuMn alloys from high-field (40 T) magnetization curves at 4.2 K

Magnetization curves of CuMn alloys with Mn concentration between 1.5 and 10 at.% have been measured at 4.2 K in fields up to 40 T, using a pulsed-field method.The results found for different concentrations can be scaled upon one another, which is a clear indication for the occurance of magnetic clusters. Analysis of this universal curve in terms of Brillouin functions yields the values $\text{z}{}_{\mathrm{I}}\text{J}{}_{\mathrm{I}}\text{/k??44K}$, $\text{z}{}_{\mathrm{II}}\text{J}{}_{\mathrm{II}}\text{/k??10K}$ and $\text{z}{}_{\mathrm{III}}\text{J}{}_{\mathrm{III}}\text{/k??0.5K}$, for the largest three interactions within each cluster.     

Level structure of 100Tc

Gamma and electron spectra following thermal neutron capture on ⁹⁹Tc have been studied with a bent-crystal spectrometer, Ge(Li) and Si(Li) detectors and a magnetic spectrometer. Prompt and delayed γ-γ coincidences with Ge(Li) detectors have been performed. A level scheme is proposed for ¹⁰⁰Tc comprising 21 excited states up to 640 keV. The binding energy of the last neutron in ¹⁰⁰Tc was deduced. For most levels, spin and parity values were assigned. Two isometric transitions of respective half-lives 10.2 and 4.6 μs have been identified using the ¹⁰⁰Mo(d, 2n)¹⁰⁰Tc reaction with a pulsed beam of deuterons. From the comparison of the present (n, γ) study and the collaborative study of the ⁹⁹Tc(d, p) reaction, several members of the multiplets $\text{π}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{ν}\text{g}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$, $\text{π}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{ν}\text{g}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$, $\text{π}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{ν}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ have been identified.     

Phenomenological predictions of the SO(10) supersymmetric grand unified model

The phenomenological predictions of the SO(10) supersymmetric grand unified model (SO(10) SGUM) for the mass scales M₁, M₂, weak angle ifsin²θ_w, quark-leptons mass ratios $\text{m}{}_{\mathrm{<mtext>b</mtext>}}\text{m}{}_{\mathrm{\tau }}$, $\text{m}{}_{\mathrm{t}}\text{m}{}_{\mathrm{<mtext>b</mtext>}}$, $\text{m}{}_{\mathrm{\tau }}\text{m}{}_{\mathrm{\nu }}{}_{\mathrm{\tau }}$ and proton lifetime τ_p are estimated by using renormalization group analysis at one-loop level. In contrast with SU(5) SGUM, we find that the SO(10) SGUM still has problems with τ_p but not with sin²θ_w and $\text{m}{}_{\mathrm{<mtext>b</mtext>}}\text{m}{}_{\mathrm{\tau }}$, which may suggest that supersymmetry would be bro at a mass scale $\text{?10}{}^7\text{GeV}$.