Experimental study of π− π+ system at low invariant-masses

We report on results of an experiment to study the reaction ^– p ^{– +} in the incident pion momentum region between 295 and 450 MeV/c. A departure from phase space was observed in invariant-mass spectra and angular distributions which cannot be explained with and resonance production. It indicates aI=0,J ^P = 0^{+ – +} final-state interaction.Deceased     

Backward production of mesons associated withΔ ++(1232) inπ + p interactions at 20 GeV/c

We have analyzed backward meson production in ⁺ p reactions at 20GeV/c, which were measured in the CERN spectrometer triggered by a fast proton (p _f ), in experiment WA56. Production via baryon exchange of quasi-two-body final states ⁺⁺ (1232) ⁰ (770), ⁺⁺ (1232)f ₂ (1270), and ⁺⁺ (1232) ₃ ⁰ (1690) is clearly identified. The density matrix elements of meson resonances and of ⁺⁺ (1232) are analyzed. We have observed also the reactions ⁺ p ⁺⁺ (1232) ⁰ and ⁺ p ⁺⁺ (1232) in thep _f ^{+ 0} andp _f ^{+ + – 0} final states.     

A new approach to the problem of the anomalous magnetic moment of the electron

A heuristic model for deriving the anomalous magnetic moment of the electron is presented. A term /2 – 0.327(/)² is deduced, in better agreement with experiment than is the QED derivation of /2 – 0.328(/)². The result is strengthened by the recent non-QED account of the Lamb shift by Yu and Sachs.     

Structural,electrical and optical properties of Cdx Zn1−xSe thin films

X-ray diffraction and electron diffraction techniques indicate that Cd_x Zn_1–xSe thin films on glass substrates have a polycrystalline nature, with sphalerite structure for x0.5 and wurtzite structure for x0.6. The crystalline size in each composition increases with increasing the film thickness. The room temperature dark resistivity varies from one composition to another showing a transition at x=0.55The temperature dependence of of the deposited films revealed two conduction mechanisms, one below 352 K due to shallow levels, surface states, and defects introduced during the film growth, and over 352 K due to deep-level ionization following the ordinary semiconducting behaviour.The thermal activation energy of the free charge carriers decreases linearly with increasing the molar fraction x of the CdSe content up to x=0.55, above which it increases with increasing x.The optical constants of Cd_x Zn_1–xSe thin films of different compositions were determined in the spectral range 400–2000 nm. The analysis of the absorption coefticient at and near the absorption edge indicates the existence of allowed direct transition energy gaps decreasing with increasing x.     

Nonlinear piezoresistance in p-type silicon

An investigation was made of the longitudinal and transverse piezoresistance and electrical conductivity of p-type silicon under conditions of uniaxial compression, x [111], in the temperature range 77–300°K and hole concentration range 2.10¹⁵–5.10¹⁸ cm^–3. The transverse component of the electrical conductivity tensor, [11¯2], was found to depend nonmonotonically on the degree of compression. Compression decreases ₄₄ and increases the combination ₁₁ + 2₁₂. The nonlinearity oi the longitudinal piezoresistance increases with increasing hole concentration and T = 77°K. The results are explained by the rearrangement of the valence band under the deformation and the formation near the top of this band of a section of the spectrum described in the approximation of low energies of Pikus-Bir theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 3–7, October, 1980.     

Scalar mesons in ππ and K¯K scattering

The s-wave pion scattering amplitude is analysed with the aim to clarify the mass spectrum of scalar mesons and to find evidence of lightest glueball. The S-matrix and K¯K coupled channel formalism is used. The existence of scalar mesons S^* and is implied by the data. The production K¯K and the elastic K¯KK¯K coupled amplitudes are predicted from the scattering data. The couplings c f S^* to and K¯K states are determined.     

ρ0 production the reaction ξξ→3π+3π?ξξ→ρ0ρ0(1700)

We have studied the ⁰ production rate in the reaction 3⁺3^– in the energy range 1.6W 7.5 GeV with the CELLO detector at PETRA. Our analysis points to a substantial yield of ^00+– events in particular atW >4.0 GeV. We give cross sections for the ⁰2⁺2^– and ^00+– final states and calculate upper limits for the reaction ⁰⁰ (1700) ^00+–.Now at CERN     

Calculation of Ratios of μ and π Masses to the e Mass for a Simplified Model with a Square-Well Potential

In the present paper, the feasibility of constructing a model of elementary and particles based on the Poincaré model of the electron [1] is examined with allowance for schemes of particle decay. The muon and pion in stopped states are considered as spherical resonators for virtual neutrino quanta excited inside an elastic lepton shell; the number of these quanta is determined by the scheme of the corresponding particle decay. In the model, the muon differs from the electron by two additional quanta of the neutrino field. The e, , and masses are calculated with the help of a single parameter. The ratio of and e masses is about (6c/e ²)^2/3, and the ratio of ° and e masses is (3/2)^2/3. The calculated e, , and ° masses are in the 0.547:105.71:134.963 ratios, which is in good agreement with the available experimental data. The calculated electromagnetic radius of the charged pion (±) = 0.5f is close to that calculated from the experimental data. The neutrino mass _e is found to be m( _e ) 0.02 eV.     

Semiclassical theory of the scattering of π-mesons by nucleons in the case of strong coupling. Part I

The scattering cross section of the reaction + N N + , + N N + is calculated by the semiclassical method. It is predicted that the latter reaction occurs through N** resonance. The mass of this resonance, the spin, and isospin are found. The zero approximation with respect to the coupling constant between the - and -mesons is considered.     

Quantum Chemical Calculation of the Spectral Luminescent and Physicochemical Properties of Anisidines

The influence of the position of a methoxy group in the phenyl radical of aniline on the spectral, geometric, and photophysical characteristics, and also on the proton-donating and proton-accepting properties of the free molecules of o-, m-, and p-anisidines is investigated by the methods of electron spectroscopy and quantum chemistry. The energy levels of the singlet and triplet states of anisidines are calculated. For all the anisidines the band in the intermediate spectral region is shown to be formed by two electron transitions of the ^*- and ^* type of different intensity.     

Role ofh 11/2 protons in144Pm

High spin states of the N=83 nucleus¹⁴⁴Pm have been studied using the reaction¹³⁰Te(¹⁹F,5n) and the techniques of gamma-ray and conversion electron spectroscopy. Empirical shell model calculations indicate that three observed states with J=14, 15 and 16 haveh ₁₁ ^2/2 configurations. This is the first observation ofh ₁₁ ^2/2 states in a Z<64, n="83">This work was supported by the National Science Foundation and the State of Florida.     

Electroproduction of π0 mesons on the deuteron and neutral weak currents

An investigation is made into P-odd effects due to neutral weak currents in the process of electroproduction of ⁰ mesons on the deuteron, e^–+d e^–+⁰+d. The general structure of the differential cross section of this reaction (with allowance for the interference between the amplitudes of the electromagnetic and weak mechanisms) is obtained for the experimental conditions when the scattered electron and ⁰ meson are detected in the final state.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 17–21, September, 1980.     

On the possibilities to study the exotic state 1−+ in photoproduction of the πη, πη′ systems

We show that photoproduction experiments provide propitious conditions to study the exotic state 1^–+ in the and channels. For unpolarized photons contributions from natural and unnatural parity exchanges do not interfere with each other, a fact which permits to estimate the correctness of phase shift analyses. In photoproduction of the ⁺ system in the mass range ofa ₂(1320) a more stringent limit on the product (1^–+)Br(1^–+) can be obtained than in experiments on Primakoff production on nuclei. Particularly favourable is the study of the state 1^–+ in the coherent photoproduction of the ⁰ and ⁰ systems on nuclei, with significantly enlarged statistics and a simplified phase shift analysis.     

Measurement of atomic capture probabilities of negative pions in metal hydrides

Atomic capture probabilities of negative pions in some metal hydrides were measured. The capture by a hydrogen atom was detected by means of a pair of the annihilation rays of ⁰ which had been produced by the charge-exchange reaction of ^– with the capturing hydrogen nucleus (proton). This method ensures a high sensitivity and reliability of the measurements. The probabilities obtained were in agreement with previous measurements except for palladium hydride, which showed a much smaller probability than that given in the literature. The atomic capture of ^– is well described in the framework of the large mesic molecular model, in which the proportionality constant reflects the chemical states of the capturing atoms and also the neighboring ones.     

Vibronic properties of 2-azaanthracene and its derivatives

We report an experimental and theoretical (PPP method) study of the UV absorption spectra of 2-azaanthracene and four of its methyl-substituted derivatives. We find that the p bands of these compounds consist of two different vibronic ^* bands. Our experimental and theoretical results suggest a rule for evaluating the effect of methyl groups on ^* transition energies as a function of the charge on the atoms. We interpret the reasons for the different effects of a polar solvent and hydrogen bonding on the ^* bands of these compounds.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 7–15, June, 1977.     

Laser collimation of an Fe atomic beam on a leaky transition

We report results of the first laser collimation of a thermal beam of Fe atoms on the leaky ⁵D₄ ⁵F₅ transition, with both parallel linear ^xx and crossed linear ^xy laser polarization configurations. The measured atomic beam divergence is compared to a rate-equation model and a quantum Monte Carlo model. The experimental values for the divergence are limited by the finite laser line width, which is comparable to the natural line width of the Fe atom. In general, flux decreases with higher intensities, showing the effect of the leaky transition. At the best beam collimation _RMS = 0.17 mrad, which is for a detuning of = – and a saturation parameter of s = 6, the flux decreased to approximately 70%. Highest flux was measured for a detuning of = –2 and s = 4, reaching 135% of the uncooled value. From our measurements we estimate the total leak rate to be 1/(240 ± 40), which is in good agreement with the literature value of 1/244. The crossed linear polarization configuration is the better choice, with a slightly better collimation but the same atomic beam flux. Plugging of the largest leak would increase the flux to at least 80% of the closed transition value, resulting in better contrast for atom lithography.     

Bounds to the differential cross-section for the processes p¯p→π+ −

Using scattering data, the integrated cross-section for p¯p^+–, and unitarity, we derive upper bounds to the differential cross-section for p¯p^{+ –}. Comparison with experimental data shows that in general the bounds are several times larger than the measured value, but that at certain points this factor is only about two or three.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.I would like to thank Dr. A. K.Common for useful discussions and collaboration in the early stages of this work.     

The influence of shape changes on the alpha decay in the191Bi m,g →187Tl→183Au chain

The¹⁹¹Bi^{m,g 187}T1 ¹⁸³Au a-decay chain has been studied using mass — separated sources. The a — branching ratios have been measured. Out of the reduced a — decay widths, it is clear that the s_1/2 — S_1/2 and h_9/2 h_9/2 transitions are not hindered although they involve strong shape changes.     

Weinberg Angle and Pion Beta Decay in the Spinor Strong Interaction Theory

From an isospin SU(2) × hypercharge U(1)gauge-invariant meson action for K⁺,^{+ +}, a prediction ofthe Cabbibo angle was obtained earlier. Using anotherresult of the spinor strong interaction theory that the s quark is only a littleheavier than the d quark, the above action can beextended to a weakly broken SU(3) one. The Weinbergangle is found to be 30° in the limit of this SU(3)symmetry. In the approximation and context entailing thislimit, the Weinberg angle can be removed from the listof undetermined fundamental parameters in electroweaktheory. The spinor strong interaction Lagrangian used above and applied to the decay⁺ e⁺ is shown tohold for ^{+ 0}e⁺ as well, renderingthe conserved vector current hypothesis hithertorequired to account for the latter decaysuperfluous.     

Study of the πn → π<Superscript>{-}</Superscript>π<Superscript>{-}</Superscript>p reaction at 430 MeV energy

The total cross-section for the ^{-}n ^{-}{-}p reaction has been measured at a pion kinetic energy of 430MeV in a deuterium bubble chamber. The cross-section value was found to be 0.197±0.016mb that is much smaller than the predictions of the chiral perturbation theory. The differential spectra are compared with calculations made in the framework of the model of Bolokhov et al. 13.60.LeMeson production [:AND:]13.85.LgTotal cross-sections