S12-P12-lambshift in the n = 5 and n = 6 states of ionized helium

The S_{$\text{1}\text{2}$}-P_{$\text{1}\text{2}$}-splittings in the n = 5 and n = 6 states of He⁺ have been determined by an r.f. method to be (905.2 ± 1.0) MHz and (526.7 ± 2.5) MHz, respectively (theory: 906 and 524.2 MHz). The electric fields in the resonance cell and their dependence on the experimental parameters have been examined.     

Spin selectivity of the polarised (d, 2p) reaction

Tensor polarisation observables in intermediate energy $\text{(}\text{d}\text{, 2}\text{p}\text{)}$ charge exchange on 0⁺ nuclei are investigated. It is shown that for small excitation energies of the di-proton the polarisation can help to distinguish between 0^?, 1^? and 2^? final nuclear states produced through ΔL = 1, ΔS = 1 transitions. The information to be obtained is similar to that inherent in $\text{(}\text{p}\text{,}\text{n}\text{)}$ spin transfer experiments but the deutron-induced experiments should have much higher efficiency.     

Transverse spin correlation function of the one-dimensional spin-12 XY model

The transverse spin pair correlation function p^x_n=<S^x_mS^x_m+n>=<S^x_mS^x_m+n> is calculated exactly in the thermodynamic limit of the system described by the one-dimensional, isotropic, spin-$\text{1}\text{2}$, XY Hamiltonian

$\text{H=?2J}\text{∑}\text{l=1}\text{N}\text{(S}{}^{\mathrm{x}}{}_{\mathrm{l}}\text{S}{}^{\mathrm{x}}{}_{\mathrm{l+1}}\text{+S}{}^{\mathrm{y}}{}_{\mathrm{l}}\text{S}{}^{\mathrm{y}}{}_{\mathrm{l+1}}\text{)}$

. It is found that at absolute zero temperature (T = 0), the correlation function ρ^x_n for n ≥ 0 is given by

$\text{ρ}{}^{\mathrm{x}}{}_{\mathrm{2p}}\text{=}\text{1}\text{4}\text{2}\text{π}{}^{\mathrm{2p}}\text{Π}\text{j=1}\text{p?1}\text{4j}{}^2\text{4j}{}^2\text{?1}{}^{\mathrm{2p?2j}}\text{if}\text{n=2p}$

,

$\text{ρ}{}^{\mathrm{x}}{}_{\mathrm{2p+1}}\text{=±}\text{1}\text{4}\text{2}\text{π}{}^{\mathrm{2p+1}}\text{Π}\text{j=1}\text{p}\text{4j}{}^2\text{4j}{}^2\text{?1}{}^{\mathrm{2p+2j}}\text{if}\text{n=2p+1}$

, where the plus sign applies when J is positive and the minus sign applies when J is negative. From these the asymptotic behavior as n → ∞ of |?^x_n| at T = 0 is derived to be $\text{|ρ}{}^{\mathrm{x}}{}_{\mathrm{n}}\text{| ～}\text{a}\text{n}$ with a = 0.147088?. For finite temperatures, ρ^x_n is calculated numerically. By using the results for ?^x_n, the transverse inverse correlation length and the wavenumber dependent transverse spin pair correlation function are also calculated exactly.     

The vibration spectra of the intercalation complexes TaS2·(pyridine)12 and NbS2·(pyridine)12

Using incoherent inelastic neutron scattering we have obtained the vibration spectra of the MS₂ ·(pyridine)_{$\text{1}\text{2}$} complexes (M = Nb, Ta) between 200 and 1000 cm^-1. The vibrations of the pyridine have been perturbed upon intercalation but in a different manner to that which occurs on Lewis complex formation. Implications of these results are mentioned.     

Nuclear g-factor of the 172+ isomeric state in 63Cu

The nuclear g-factor of the 4498 keV $\text{17}\text{2}$⁺ isomeric state in ⁶³Cu was measured with the in-bearn perturbed angular distribution method, through the ⁶²Ni(α, p2nγ)⁶³Cu reaction, to be g_exp = 0.184 ± 0.012. This value is in good agreement with a semiempirical g-factor for the three-quasiparticle configuration [π2p_{$\text{3}\text{2}$}(v1f_{$\text{5}\text{2}$}, 1g_{$\text{9}\text{2}$})₇]_{$\text{17}\text{2}$⁺} calculated using the experimental single-particle g-factors of neighbouring nuclei. At the same time the internal magnetic field at the Cu nuclei in Ni metal was obtained to be B_int = ?46.6 ± 1.3 kG.     

Non-perturbative QCD effects explain the ΔI = 12 rule in the chiral limit

It is shown that in the chiral limit, the enhancement of the $\text{ΔI=}\text{1}\text{2}$ transitions for mesons is explained by the large size of non-perturbative QCD matrix elements. For $\text{〈}\text{s}\text{s〉 = 〈}\text{u}\text{u〉}$ we obtain ∣M(K_S⁰ → 2π⁰) ∣ =(5.2±0.6) × 10^?7m_K in excellent agreement with experiment.     

Collisional quenching of HgBr(B2∑+12)

Rate coefficients for the quenching of HgBr(B²∑⁺_{$\text{1}\text{2}$}) by HgBr₂, H₂, CO₂, CO, O₂, N₂, Xe, and Br₂ are reported. HgBr(B²∑⁺_{$\text{1}\text{2}$}) is formed by the photolysis of HgBr₂ with the output from an ArF laser. The rate coefficients are determined by monitoring the time resolved B²∑⁺_{$\text{1}\text{2}$} → X²∑⁺_{$\text{1}\text{2}$} emission as quenching species are added. Radiative lifetimes at particular emission frequencies are also reported, and quenching mechanisms are discussed.     

Lifetime measurements of the metastable 1s2s2p 4P52 state in the lithium-like N,O and Ne

Lifetimes of the metastable three electron 1s2s2p ⁴P_{$\text{5}\text{2}$} state have been studied with a time-of-flight beam-foil technique. The lifetimes were measured to be 53.5 ± 13, 20.0 ± 3 and 10.4 ± 1.5 nsec for nitrogen, oxygen and neon respectively. Lifetimes and energies of this state are in excellent agreement with theoretical values.     

Polarized deformed spin−32 projectile scattering and complex folded potentials

A formalism is presented where polarization observables of all ranks for deformed spin ?$\text{case3}\text{2}$ projectiles are calculated in a parameter-free fashion. Complex optical potentials for the available ⁷$\text{Li}$ + ⁵⁸Ni elastic scattering data at E_lab = 20.3 MeV are obtained from single folding calculations, taking the ⁷Li ground state to be an α + t cluster in relative p-state. The expansion of the hamiltonian in spin-space generates tensor terms of ranks 2 (T_R) and 3 (T₃) apart from the usual central and spin-orbit terms. The T_R potential fits the second-rank tensor analysing powers quite well without being able to resolve discrete ambiguities of input optical parameters. The T₃ term generates a J · L contribution, making the spin-orbit interaction three-component. The ⁷Li vector analysing power so obtained is negative, but the magnitude is not fully reproduced. Modification of parameters to account for absorption modes not included in the superposition model indicates the need for properly handling dynamical polarization effects due in particular to the low-lying first excited state of ⁷Li.     

On the λλ spectroscopy in e+e− annihilation

The properties of the radial excitations of the ?, ω and ? mesons are discussed. In particular it is proposed to identify the recently observed states at √s ? 1.5, 1.82 and 2.13 GeV in e⁺e^? annihilation with the $\text{?}{}_{\mathrm{<mtext>D</mtext>}}\text{≡}{}^3\text{D}{}_1\text{(λλ), ?″}\text{and}\text{?′″}$ mesons respectively. The ?′ meson is suggested to lie in the vicinity of 1.5 GeV and strongly coupled to the ?_D. The ?″(1.6) width is also suggested to be smaller than previously reported.     

Dynamical basis for spin-12 as well as generation stability of leptons and quarks

A three-way preon interaction with a spin-dependence of the form σ_μν⁽¹⁾ σ_νγ⁽²⁾ σ_λμ⁽³⁾, is proposed for a two-flavor (t,v) preon model, within a Bethe-Salpeter framework. This mechanism not only eliminates all $\text{S =}\text{3}\text{2}$ states but severely restricts the spatial symmetries of allowed $\text{S =}\text{1}\text{2}$ states to at most threedistinct “generations” with very strong selection rules forbidding transitions among them.     

Phonon observations from 1ƒ noise measurements

From mobility fluctuation $\text{1}\text{?}$ noise parameter measurements five phononic energies corresponding to LO, TO vibrational modes as well as TA + S₂ or O, TO + TA, TO + O combined modes were identified. They stand for phonon replicas of non-radiative recombination processes. It is thus demonstrated that the carrier-phonon interaction is the source of $\text{1}\text{?}$ noise in semiconductors.     

The systematics of h112 proton alignment in 157, 158, 159Er

Rotational bands have been observed in ^{157, 158, 159}Er to very high spin ($\text{J ～ 41}\text{h}\text{?}$). Upbends are found, due to the alignment of two h_{$\text{11}\text{2}$} protons at $\text{0.40 ?}\text{h}\text{?}\text{ω ? 0.46}\text{MeV}$ in all bands. A systematic shift with neutron number of the band-crossing frequency is observed and is related to a change in quadrupole deformation ?₂.     

Electrical conduction and 1ƒ noise in Li-DOPED MnO

Electrical resistivity, thermoelectric power and current noise were measured on Li-doped MnO single crystals in the temperature range from 300 to 1000 K. Below 700 K the crystals are p-type and the activation energy of the resistivity is 0.75 eV. Around 700 K the activation energy changes from 0.75 to 1.25 eV owing to a change from p- to n-type conduction. The depth of the Li acceptor is found to be 0.65 eV. From resistivity and thermoelectric power data it is concluded that the bandgap in first approximation can be written as E_s(T) = E_o ? γT between 750 and 1000 K, with E_o = 1.9 eV and γ = 6 × 10^?4 eV/K. The current noise spectra show $\text{1}\text{?}$ noise. The magnitude of the $\text{1}\text{?}$ noise is strongly temperature dependent. From the noise data it is deduced that E_o = 2.2 eV and γ = 10^?3 eV/K in the temperature range 430–700 K.     

|ΔI| = 12 rule in non-leptonic weak interactions with Han-Nambu quarks

Gauge theories of weak and electromagnetic interactions involving Han-Nambu quarks are constructed with the following features: small $\text{K}{}_{\mathrm{<mtext>L</mtext>}}\text{→ μ}\text{μ}$ amplitude and K_L - K_S mass-splitting; a non-leptonic effective Lagrangian ΔY = ± 1 leading to the usual soft-pion theorems and obeying a fundamental $\text{|ΔI| =}\text{1}\text{2}$ rule, with corrections of order θ²_Cabibbo.     

Origin of 1ƒ noise

$\text{1}\text{?}$ noise dependence on temperature for both n- and p-type silicon has been measured. The formula for calculation of $\text{1}\text{?}$ noise is presented. The formula has been derived by presumption that only lattice scattering gives $\text{1}\text{?}$ noise. A good agreement between calculations and experimental results is found.     

E2 transition rates and seniority mixing in the proton 1g92 orbit

The half-lives of the lowest $\text{21}\text{2}$⁺ states in ${}^{91}\text{Nb}$ and ${}^{93}\text{Tc}$ were measured with the pulsed beam direct timing method. The results are $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 0.92 ± 0.10}\text{ns}$ and 1.61 ± 0.10 ns for ${}^{91}\text{Nb}$ and ${}^{93}\text{Tc}$, respectively. The known experimental data on E2 transition rates in N = 50 nuclei are analysed in the light of a suggested seniority mixing in the proton $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$. orbit. It is concluded that the E2 matrix elements cannot be explained satisfactorily in the proton $\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ model space, even if free seniority mixing is allowed.     

A numerical estimate of deviations from the exponential decay law for the transition 2P12→1S12 in hydrogen

The deviations from the exponential decay law of the $\text{2}\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ states of the Dirac hydrogen atom with respect to the transition $\text{2}\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{→1}\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ are numerically estimated. We find |a₀(t) ? exp(?λt)|?2.5 × 10^?4 for all t, where a₀(t) is the “exact” decay amplitude and λ is a complex constant such that (2Re λ)^?1 is the “natural lifetime” of the $\text{2}\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ states with respect to the spontaneous transition to $\text{1}\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$.     

The rotational bands 12+[411]and 12−[541]in 175Lu

In a study of the γ-radiation emitted in the reaction ¹⁷⁶Yb(p, 2n) excited states of the nucleus ¹⁷⁵Lu up to spin I = $\text{13}\text{2}$ have been investigated. The main results concern the rotational bands $\text{1}\text{2}$⁺ [411]and $\text{1}\text{2}$^? [541]with the corresponding band heads found at 626.60 and 370.88 keV, respectively. The half-life of the $\text{1}\text{2}$⁺[411] level has been determined to be $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 10.7±0.5}\text{ns}$. Furthermore, the band heads $\text{3}\text{2}$^?[532]and $\text{3}\text{2}{}^{\mathrm{+}}$[411]are proposed at energies of 999.0 and 1150.8 keV, respectively. Experimental E1 transition probabilities between both $\text{K =}\text{1}\text{2}$ bands are compared with calculations including the Coriolis and pairing effects, as well as theoretically deduced quadrupole deformation parameters.     

Some studies of T = 32 states in 17F

Measurements have been made of some parameters of the second and sixth $\text{T =}\text{3}\text{2}$ states in ¹⁷F. For the second state, the resonance energy was found to be E_p = 12.707 ± 0.001 MeV (E_n = 12.550±0.001 MeV), which agrees with and improves on the accuracy of earlier work. For the sixth $\text{T =}\text{3}\text{2}$ state, at E_p = 14.435 MeV, the γ-decay was determined to be predominantly γ₀ with a branch to the first excited state of Γ(γ₁)/Γ(γ₀) ≦ 0.14. Together with other work, this determines J^π to be $\text{3}\text{2}{}^{\mathrm{?}}$. The capture strength is found to be (2J + 1)Γ_pΓ_γ/Γ = 11.4 ± 2.6 eV.