Inelastic scattering and satellite fine structure in the high-resolution uv photoelectron spectrum of CS2

The outer valence region in CS₂ has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X$\text{\$}\text{?}$²Π_g, A$\text{\$}\text{?}$²Π_u, B$\text{\$}\text{?}$²Σ⁺_u and C$\text{\$}\text{?}$²Σ⁺_g bands. Some of the fine-structure peaks in the X$\text{,}\text{?}$B$\text{\$}\text{?}$and C$\text{\$}\text{?}$bands are shown to be pressure-dependent. The reason for the pressure dependence is assumed to be inelastic scattering of electrons emitted in the adiabatic transitions. It is established that the two CI satellite bands present in the He(I)-excited spectrum contain vibrational structure.     

Nucleon-antinucleon resonances near threshold: A possible explanation of the S(1930) meson

We suggest a dynamical mechanism (dominance of isoscalar meson exchange) which leads to an interpretation of the S(1930) meson in terms of a doublet of $\text{N}$N resonances with J^πC(I^G)=2^?+(0⁺, 1^?). The presence of a doublet implies constructive interference in the $\text{p}$p → $\text{p}$p elastic channel and destructive interference in the $\text{p}$p → $\text{n}$n channel, in agreement with recent experimental evidence. Possible spin and isospin assignments are suggested for other structures seen in $\text{N}$N cross sections near threshold.     

Polarization transfer in the 2H(d,n)3He reaction at θ = 0°

The vector polarization transfer coefficient K_y^y′ and the tensor analyzing power A_zz have been measured for the ²H($\text{d}$$\text{n}$)³He reaction at θ = 0° over an incident deuteron energy range from 1 to 15 MeV in 0.5 MeV steps. The results agree with the previous ²H($\text{d}$$\text{n}$)³He measurements of Simmons et al. and are nearly identical to the ²H($\text{d}$$\text{n}$)³H measurements of Clegg et al. in the region of overlap. The present results provide an accurate and complete set of the observables necessary to use the ²H($\text{d}$,$\text{n}$)³He reaction as a source of polarized neutrons.     

Relativistic Hartree-Fock oscillator strengths for the lowest s→p and p→d transitions in the first few members of the Ag(I) and Au(I) isoelectronic sequences,with allowance for cope polarization

Relativistic, single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→np²P_{$\text{1}\text{2}$$\text{3}\text{2}$} and np²P_{$\text{1}\text{2}$$\text{3}\text{2}$}→nd²D_{$\text{3}\text{2}$$\text{5}\text{2}$} transitions in the first few members of the silver (n = 5) and gold (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. Core polarization is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained are compared with available experimental data and the influence of core-polarization effects on oscillator strengths is discussed.     

Evidence for assignment of 14.0 MeV state in 11B from 10B(n,n)10B

The differential cross section and polarization for neutrons scattered from ¹⁰B have been measured at E_n = 2.63 MeV (E_x = 13.85 MeV). The results of this experiment and other available neutron scattering data in the range 1 < E_n < 4 MeV are interpreted through a single-level R-matrix calculation over the region 12 < E_x < 15 MeV. Based on this analysis the most probable J^π assignment for the 14.0 MeV level in ¹¹B is $\text{11}\text{2}{}^{\mathrm{+}}$. The anomaly near E_x = 13.1 MeV can only be explained in terms of two overlapping levels having assignments of ($\text{5}\text{2}$, $\text{7}\text{2}$)^? and ($\text{3}\text{2}$, $\text{5}\text{2}$, $\text{7}\text{2}$)⁺.     

Photon statistics in saturated m-photon amplification and attenuation of coherent light

The change of photon statistics of a nearly coherent single-mode light beam travelling through a saturable m-photon-amplifying or absorbing medium (m = 1, 2, …) is theoretically investigated. With the help of an approximation scheme valid for $\text{n}$ ? 1, Δn² ? $\text{n}$² ($\text{n}$ mean value and Δn² variance of the photon number) an analytical expression is derived for the quantity Δn²/$\text{n}$. The results holds for arbitrary values of the initial population inversion and of the degree of saturation. It turns out that for both amplification and attenuation processes after sufficiently strong interaction Δn²/$\text{n}$ tends to an asymptotic value.     

Thermal changes in the optical properties of SnSxSe2−x crystals

Optical measurements on crystals in the series SnS_xSe_2?x for 0 ? x ? 2, have yielded information on the changes in the ordinary refractive index $\text{Δn}\text{ΔT}$ and the energy gap $\text{ΔEg}\text{ΔT}$ in the temperature range 125–425 K. The coefficient $\text{Δn}\text{ΔT}$ has values +40 to +160 × 10^?6K^?1 and this confirms that covalent bonding predominantly exists in these materials. The coefficient $\text{ΔEg}\text{ΔT}$ remains fairly consistent for all values of x with an average value of -8.0×10^-4eV K^-1.     

Jψ and ψ′ decays into two hadrons

Branching ratios have been determined for the decays of $\text{J}\text{ψ}$ and ψ ′ into π⁺π^?, K⁺K^?, $\text{p}\text{p}$, π^±?^? and $\text{K}{}^{\mathrm{\pm }}\text{K}{}^1\text{(892)}{}^{\mathrm{?}}$. Results on a search for other two body decays of $\text{J}\text{ψ}$ and ψ′ are given. Also presented are values for the π and K from factors at $\text{s}\text{= 3.1}\text{and}\text{3.7}\text{GeV}$.     

Coulomb excitation of 115Sn

Coulomb excitation of the nucleus ¹¹⁵Sn was studied with beams of ⁴He and ¹⁶O. Level energies, spins, mean-lives and B(E2) and B(M1) transition probabilities were obtained. Spin $\text{3}\text{2}$⁺ states were observed at 497.35 and 1280.08 keV and spin $\text{5}\text{2}$⁺ states were observed at 986.54 and 1416.78 keV. A state of 612.79 keV was observed to be indirectly excited by decay of the Coulomb excited states. Eleven B(E2) values and nine B(M1) values were obtained for the transitions between the low-lying states. In contrast to previous particle transfer results which suggested a clear distinction between shell-model and collective $\text{3}\text{2}$⁺ and $\text{5}\text{2}$⁺ states, our results suggest the collective strength is shared by the two $\text{3}\text{2}$⁺ and two $\text{5}\text{2}$⁺ states.     

Spin and lifetime of the ω− hyperon

A total of 101 ω^? decays have been found in K^?p interactions at 10 and $\text{16 GeV}\text{c}$. The decay angular distribution has been fitted under the assumptions that the ω^? has spin either $\text{1}\text{2}\text{or}\text{3}\text{2}$. It has been found that the probability of isotropy (spin$\text{1}\text{2}\text{)}$ is less than one in a thousand, whereas the probability for spin $\text{3}\text{2}$ is about 70%. Thus, we exclude the spin $\text{1}\text{2}$ assignment. The lifetime of the ω^? is found to be (1.41_?0.24^+0.15) × 10^?10s, in agreement with our earlier result based on about $\text{1}\text{5}$ of the present sample.     

Quasi-multiplication and 1-algebras

Let $\text{B}$ be a ¹-algebra with identity. With $\text{B}$ we associate a quasi-algebra Q($\text{B}$) consisting of sequences whose entries are elements of $\text{B}$. For A,B in $\text{B}$ we give general expansions pertaining to (A+B)ⁿ, e^A+B and e^Ae^B. We also discuss the case where $\text{B}$ is the ¹-algebra generate creation and annihilation operators. Another example deals with the ¹-algebra of field operators.     

Electromagnetic transitions in 51Mn

The nuclear structure of ⁵¹₂₅Mn was studied by γ-ray spectroscopy in the ⁵⁴Fe(p, α)⁵¹ Mn reaction (E_p = 9.0–13.2 MeV) and the ¹⁴N+³⁹K, ¹⁶O+⁴⁰Ca and ¹⁴N+⁴⁰Ca fusion-evaporation reactions (E_beam = 36 MeV). In the ⁵⁴Fe(p, αγ)⁵¹Mn reaction γ-rays were detected in coincidence with α-particles emitted near 180°; mean lifetimes and γ-ray mixing and branching ratios were deduced from Doppler shift attenuation and α-γ angular correlation measurements, respectively. Definite spin assignments are: 237 and 2416 keV, $\text{J}{}^{\mathrm{\pi }}\text{=}\text{7}\text{2}{}^{\mathrm{?}}$; 1140 keV, $\text{9}\text{2}$^?; 1488 keV, $\text{11}\text{2}$^?; 1825 and 2140 keV, $\text{3}\text{2}$^?. The results for other states below 3 MeV are consistent with the existence of rotational bands (/kh²/2/OI/t~ 95 keV) built on the ($\text{3}\text{2}$⁺) 1817 keV and $\text{1}\text{2}$⁺ 2276 keV hole states. The various measurements together with an earlier value for the lifetime of the first-excited state determine unambiguously the B(M1) and B(E2) values for all of the decay branches of the $\text{7}\text{2}$^?, $\text{9}\text{2}$^? and $\text{11}\text{2}$^? lowest three excited states. From the γ-singles and γ-γ coincidence observations with fusion-evaporation reactions, the yrast cascade proceeds through these three states and higher states at 2957, 3250,3680 and 4139 keV which are suggested to have $\text{J}{}^{\mathrm{\pi }}\text{=}\text{13}\text{2}{}^{\mathrm{?}}$, $\text{15}\text{2}$^?,$\text{15}\text{2}$^? and $\text{19}\text{2}$^?, respectively. The various experimental results for the $\text{5}\text{2}$^? → ($\text{19}\text{2}$^?) yrast states are in good overall agreement with shell-model calculations in the (f_{$\text{7}\text{2}$}¹ space.     

The photoelectron angular distributions of HBr and HI AT hν = 21.2 eV

Photoelectron angular distributions for the ²Π_{$\text{3}\text{2}$, $\text{1}\text{2}$}(pπ)^?1 and ²Σ_{$\text{1}\text{2}$}⁺(pσ)^?1 ionic states of HBr and HI have been measured at a photon energy of 21.2 eV. The asymmetry parameters for the highly localized pπ orbitals closely follow those of the “lone-pair” orbitals of the related CH₃X molecules and the outer np atomic orbitals of the corresponding united atoms. Furthermore, the asymmetry parameters for the ²Π_{$\text{3}\text{2}$} and ²Π_{$\text{1}\text{2}$} states were found to be equal within experimental uncertainty, despite the large spin—orbit splittings of these heavy molecules. The asymmetry parameters for the ²Σ⁺(pσ)^?1 ionic states are significantly smaller than for the ²Π(pπ)^?1 states, in contrast to recent predictions based on angular momentum transfer theory.     

High pT π0 production from αα and αp collisions at the CERN ISR

The invariant cross sections for π⁰ meson production in alpha—alpha and alpha—proton collisions at the ISR were meas- ured up to transverse momenta of $\text{7}\text{GeV}\text{c}$ and $\text{8}\text{GeV}\text{c}$, respectively. These measurements are compared with π⁰ production in pp collisions at the same values of $\text{s}\text{/}$nucleon, and the variation of the nuclear A-dependence with p_T is determined.     

Experimental comparison of Jψ production by π±, K±, p and p̄ beams at 39.5 GeV/c

Measurements have been made of relative production cross sections of the $\text{J}\text{ψ}$ by π^±, K^±, p and p? at 39.5 GeV/c incident on copper. $\text{J}\text{ψ}$ production rates from π^?, K^? and p? are similar. The $\text{J}\text{ψ}$ relative particle/anti-particle production cross sections for x>0 are $\text{σ(π}{}^{\mathrm{+}}\text{)}\text{σ(π}{}^{\mathrm{?}}\text{)=(0.87±0.14)}$, σ(K⁺)/σ(K^?)=(0.85±0.5) and $\text{σ(}\text{p}\text{)}\text{σ(}\text{p}\text{?}\text{)=(0.15 ±0.08)}$. The small p/p? cross section ratio disagrees with models of J/ψ production by gluon amalgamation.     

KMS condition in a Schrödinger picture of the dynamics

Given the C¹-algebra $\text{A}$ of observables, the KMS condition is formulated in terms of the time evolution α¹_t of a set $\text{S}$₀ ? $\text{S}$($\text{A}$) of “physical” states subject to certain natural conditions. α¹_t need not be defined by an automorphism group of $\text{A}$. It is shown that, for a KMS state ω, α¹_t induces a 1-automorphism α^ω_t of the von Neumann algebra π_ω($\text{A}$)″ generated by the representation π_ω belonging to ω.     

Relaxation of the 4G92 state of Nd3+ in LaCl3 and Nd3+ in La(Cl99.6Br0.4)3

The decay of the ⁴G_{$\text{9}\text{2}$} state of Nd³⁺ in LaCl₃ and La(Cl_99.6 Br_0.4)₃ was measured after pulsed laser excitation as a function of temperature. The decay rate is shown to depend besides the radiative transition on single-phonon relaxation between the states ⁴G_{$\text{9}\text{2}$} ($\text{μ =}\text{1}\text{2}$) and ⁴G_{$\text{9}\text{2}$} ($\text{μ =}\text{3}\text{2}$) and on multiphonon orbit-lattice relaxation from ⁴G_{$\text{9}\text{2}$} to ²G_{$\text{9}\text{2}$}. Partial substitution of Cl by Br only alters the radiative lifetime.     

Determination of some atomic-state densities in an Xe-Br2 mixture

The atomic-state densities of the 6s[1 $\text{1}\text{2}$]⁰ metastable Xe energy level and of the 5s⁴P_{$\text{1}\text{2}$}, 5s⁴P_{$\text{3}\text{2}$} and 5s⁴P_{$\text{5}\text{2}$}Br energy levels in an Xe-Br₂ mixture have been determined as a function of current strength.     

On universality for area-preserving maps of the plane

We present detailed evidence that one-parameter families of area-preserving maps exhibit cascades of period doubling with universal geometric scaling in the parameter. We relate this behaviour to a fixed point equation of the form

$\text{Λ}{}^{\mathrm{?1}}\text{°Φ°Φ°Λ = Φ}$

and

$\text{det}\text{DΦ = 1}$

, Φ:$\text{R}$²→$\text{R}$². In particular we argue that the scaling transformation Λ:$\text{R}$²→$\text{R}$² is conjugate to the transformation Λ₀:(x, y)→(λx, μy), with λ² ≠ μ, and in fact λ² >μ. We present some numerical evidence that

$\text{δ = 8.721}$

…,

$\text{?}\text{1}\text{λ}\text{= 4.018}$

…,

$\text{1}\text{μ}\text{= 16.36}$

…, where δ is the asymptotic ratio of the differences of the parameter values corresponding to the successive periods 2^k described above.     

Spins of the levels and multipole mixing ratios of transitions in 125Sb determined from γ-γ directional correlation and polarization-directional correlation measurements

In order to resolve several discrepancies in spin assignments to levels in ¹²⁵Sb, directional correlations and polarization-directional correlations have been measured for several γ-γ cascades in ¹²⁵Sb populated from the decay of ¹²⁵Sn. Earlier results obtained from using NaI and Ge(Li) and NaI detectors were difficult to interpret due to the complex structure of the decay scheme. To improve the experimental situation, we have used two coaxial Ge(Li) detectors for the angular correlation measurements and a coaxial Ge(Li)-planar Ge(Li) combination for the polarization-directional correlations. Combination of the results of these measurements give unique spin assignments of $\text{11}\text{2}$^?, $\text{11}\text{2}$^?, $\text{9}\text{2}$⁺, $\text{11}\text{2}$⁺ and $\text{9}\text{2}$⁺ to the 1982 keV, 1890 keV, 1420 keV, 1089 keV and 1067 keV levels, respectively. The determined E2/M1 mixing ratios are : δ(470) = 0.010±0.027, δ(1067) = ?0.86±0.18, and δ(916) = ?0.02±0.01.