Excess noise of the silicon surface barrier detectors

From our experiments the following conclusions follow:

On the construction of monopoles for the classical groups

ForG a classical group, an equivalence is exhibited between:

A unified formalism for γγ→meson and ψ-γX with possible tests for hybrid and gluonic hadrons

The couplings of conventional and hybrid mesons to (real and virtual) and their production amplitudes in M are described in a unified manner. Existing results for heavy quarks are recovered, extensions to light quarks and to virtual couplings are made and phenomenological applications discussed. In particular we discuss relativistic corrections to 0⁺, 1⁺, 2⁺ for both real and virtual photons and offer a resolution to a long standing puzzle in perturbative QCD concerning the helicity structure of 2⁺⁺. We suggest that the production off ₂ (1720) involves gluons in an essential way or that this meson hasJ2.     

Investigation of nematic order by coherent neutron scattering

The mathematical relationship between the orientational order parameters and the coherent neutron scattering cross section for a nematic liquid crystal is given. For deuterated para-azoxyanisole the single-molecule part of the cross section is evaluated within the meanfield approximation and combined with experimental results to give information about molecular orientational order in terms of P ₂, P ₄ and P ₆. Both P ₂ and P ₄ are found necessary for describing the molecular order. Discrepancies between experimental and theoretical results are interpreted as possibly reflecting the inadequacy of the meanfield theory of Maier and Saupe.     

Diffractive production of ρ-mesons and of ρπ-systems by neutrinos and antineutrinos on protons

Evidence is presented for diffractive production of -mesons and of -systems invp and chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeVE _v <60 gev=" the=" cross=" sections=" for=" diffractive="> and diffractive production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive signal is consistent with being entirely due to diffractivea ₁ production. However, the data cannot distinguish between diffractivea ₁ and diffractive nonresonant production. The experimental distributions ofW, Q ²,x _Bj andy _Bj for diffractive and events are consistent with model predictions.     

Aspects of χ and ψ production in polarized proton-proton collisions

Several topics of relevance to low transverse momentum and _1,2(c ) production in polarized proton-proton collisions are discussed. The leadingO( _S ³ ) contributions to the lowp _{T 1} production cross-sections viagg, qg, andq initial states are calculated as well as the corresponding spin-spin asymmetries. We find that ₁ production increases relative to direct and ₂ production, providing up to 25% of the observablee ^* e ^– pairs arising from decays inpp collisions at s=500 GeV. The spin-dependence of ₁ production, however, is much smaller than for either direct or ₂ production and so will likely be far less useful than either process in probing the polarized gluon structure function of the proton. A subset of theO( _S ³ ) radiative corrections to ₂ production involving initial state quarks are also performed and compared to leading ordergg₂ predictions.     

Rescattering mechanisms for\bar p p→φX and the OZI rule re-examined

The OZI suppressed reactions¯pp and¯pp are reanalyzed, evaluating the unitarity contributions from two meson intermediate states with full spin, partially correcting earlier results. An estimate for¯pp without spin is also given. Together with earlier VDM results for¯pp the conservative estimates reported here easily explain the observed rates for all the meson channels considered.It is a pleasure to thank the following colleagues for numerous discussions: C. Amsler, D. Buzatu, O. Gortchakov, F. Lev, J.-M. Richard and M.G. Sapozhnikov.     

The structure of28Si above 10 MeV excitation energy I: gamma-decay modes and radiative widths of levels

The systematics of-decay modes and radiative widths of highly excited states in²⁸Si has been extended by taking-ray spectra on 60 resonances of the²⁷Al(p,) reaction in the range 1097 keVE _p 4492 keV (12643 keVE _x 15915 keV) and on the²⁴Mg(,) resonances atE =3355, 3431, 4003 keV (E _x =12860, 12925, 13 415 keV). The-decay modes of levels in the sub-resonance region (E _x =10–12.5 MeV) were studied with both the²⁷ A1(p, ) reaction and the²⁷ A1(d, n) reaction at E_d=4,5,6 MeV. Information on radiative widths of levels was obtained by measuring the resonance strengthsS =(2I+1) _p / for 52 resonances of the²⁷Al(p, ) reaction with an emphasis on prospective T=1 states.     

Some consequences of the conformally invariant generalization of Einstein’s equations

New possibilities in the solution to the general relativity problems appearing in the conformally invariant generalization of Einsteins equations are addressed. The conformally invariant equations and their solutions possess the following properties:

A mini transmissionγ-ray Compton polarimeter and measurements of the sign of magnetic moments of radioactive nuclei

A mini transmission-ray Compton polarimeter was developed for the measurement of the sign of magnetic moments of radioactive nuclei with low-temperature nuclear orientation. The signs of the magnetic moments of the following isotopes were determined:¹⁹³Os [=+0.7297(16) _N];^191m Ir [=+6.20(9) _N];¹⁹²Ir [=+1.924(10) _N];¹⁹⁴Ir [=+0.39(1) _N];^195m Pt [=–0.605(15) _N].Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday     

Observation of isomeric states in197Bi

The high spin states of¹¹⁹Te, populated in¹¹⁰Pd(¹³C,4n) and¹¹⁰Pd(¹²C,3n) reactions, have been studied through -ray spectroscopy. The level scheme has been established upto a spin of 55/2. Three-quasiparticle states, based on g² _7/2h_11/2 and g_7/2d_5/2h_11/2 configurations, have been identified. The 35/2 and 39/2 states are suggested to be the fully aligned states constituted by five valence h_11/2 ³, g_7/2, d_5/2 quasiparticles.     

Fast-hadron formation mechanism in leptoproduction in nuclei

The mechanism of fast-hadron leptoproduction in nuclei in deep inelastic region is considered. Different possible mechansims of fast-hadron formation in the virtual-photon fragmentation region and the process of transition of the quark (quark-gluon system) through nuclear matter is analysed. The range of consistency of the SLAC and EMC CERN data on meson leptoproduction in different nuclei is obtained to be 0.2 GeV²m _c ² 0.5 GeV². It is shown that the kinematic region 0.05x _B 0.3 and (3–5)Q ²/m _c ² 100 is the most favourable for an investigation of the growth law (evolution) of the transverse dimensions of quark (quark-gluon system) produced by the virtual photon.     

Upper limit for thermal direct photon production in heavy-ion collisions at 60 and 200A·GeV

The production of direct photons has been investigated in reactions ofp and¹⁶O projectiles at 60 and 200A·GeV with C and Au nuclei. Photon and ⁰ spectra have been measured in the pseudorapidity range 1.52.1 for the transverse momentum region 0.4 GeV/cp _T 2.8 GeV/c employing the lead-glass spectrometer SAPHIR. An upper limit of 15% at the 90% confidence level for the direct photon signal relative to the neutral pion production is obtained from the comparison of measured photon spectra with Monte Carlo simulations of the hadronic background based on the reconstructed yield of ⁰ and mesons. Consequences for a possible phase transition to a quark-gluon plasma are discussed.     

Further Results on the Smoothability of Cauchy Hypersurfaces and Cauchy Time Functions

Recently, folk questions on the smoothability of Cauchy hypersurfaces and time functions of a globally hyperbolic spacetime M, have been solved. Here we give further results, applicable to several problems:

Association energy of divalent and monovalent impurities with edge dislocations in NaCl

In the present paper calculations have been made of the association and interaction elastic energies for monovalent cation impurities and divalent cation impurities unassociated and associated with cation vacancies in the form of dipoles with dislocationsa/2 r _{+ +} < r_{Ca ^{+ +}} r_{ + + }< r_{Ca^{ + + } } in the compressed region of dislocation, mainly on the dislocationa/2110 {100}. In the case of divalent impurities associated with cation vacancies in the form of dipoles the increase in impurity concentration can take place at all impurities as in the above mentioned case and additionally Sr⁺⁺

Measurement of γp→K + Λ and γp→K + Σ 0 at photon energies up to 1.47 GeV

The reactions pK ⁺ and pK ^{+ 0} have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the polarization and, for the first time, the ⁰ polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°–180°). The polarization of both and ⁰ is substantial at all energies and varies strongly with the production angle.This work is supported by the Bundesminister für Forschung und Technologie (BMFT), FK 06 BN 621 I     

Die magnetische Suszeptibilität der ternären Systeme halbleitender Verbindungen

Zusammenfassung Im vorliegenden Artikel wird der Versuch unternommen, die für die Suszeptibilität der binären Systeme zutreffenden empirischen Beziehungen auf die ternären halbleitenden Systeme auszudehnen. Die Richtigkeit der Erwägungen wird an den Systemen Zn-Cd-Sb, In-Ga-Te und an einigen festen Lösungen anderer halbleitender Verbindungen überprüft. Im Artikel wird weiter gezeigt, daß sich im Falle, wenn sich die Suszeptibilitäten der Komponenten des ternären Systems additiv verhalten, zur Berechnung der molaren Suszeptibilität einer festen Lösung die Mischungsregel verwenden läßt, was im Gegenteil in diesem Falle als Kriterium dienen kann, ob zwei den Erfordernissen der Additivität der Suszeptibilitäten der Bestandteile Genüge leistende Stoffe eine feste Lösung oder ein mehrphasiges System bilden.

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