Six-fermion calculation of intermediate-mass Higgs boson production at future {e^+ e^-} colliders

The production of an intermediate-mass Higgs boson in processes of the kind fermions at the energies of future linear colliders is studied. The recently developed and fully automatic algorithm/code ALPHA is used to compute the tree-level scattering amplitudes for the reactions . The code has been interfaced with the Monte Carlo program HIGGSPV/WWGENPV, properly adapted to 6-fermion production, in order to provide realistic results, both in the form of cross sections and event samples at the partonic level. Phenomenological results, that incorporate the effects of initial-state radiation and beamstrahlung, are shown and commented, emphasizing the potentials of full six-fermion calculations for precise background evaluation as well as for detailed studies of the fundamental properties of the Higgs particle. Received: 22 May 1997 / Published online: 20 February 1998     

Can the Local Energy-Momentum Conservation Laws be Derived Solely from Field Equations?

The vanishing of the divergence of the matter stress-energy tensor for General Relativity is a particular case of a general identity, which follows from the covariance of the matter Lagrangian in much the same way as (generalized) Bianchi identities follow from the covariance of the purely gravitational Lagrangian. This identity, holding for any covariant theory of gravitating matter, relates the divergence of the stress tensor with a combination of the field equations and their derivatives. One could thus wonder if, according to a recent suggestion [1], the energy-momentum tensor for gravitating fields can be computed through a suitable rearrangement of the matter field equations, without relying on the variational definition. We show that this can be done only in particular cases, while in general it leads to ambiguities and possibly to wrong results. Moreover, in nontrivial cases the computations turn out to be more difficult than the standard variational technique.     

On a theorem by do Carmo and Dajczer

We give a new proof of a theorem by M.P. do Carmo and M. Dajczer on helicoidal surfaces of constant mean curvature.

     

A new model for the discharge behaviour of metal-nitride-oxide-silicon (MNOS) non-volatile memory devices

A new model is presented for the discharge mechanism of MNOS memory devices. For moderate and large charge contents the discharging effect can actually be ascribed to the compensation of the stored charge by the injection from the silicon into the nitride of carriers of the opposite type.     

Anwendung der Ionenstrahl- und Plasma?tztechnik in der elektronischen Feinstrukturierung und ihre analytische Problematik anhand praktischer Erfahrungen

Zusammenfassung Die Herstellung feinstrukturierter Schaltungen in der Elektronik hat zu neuen Strukturierungsverfahren geführt, die heute im Produktionsmaßstab eingesetzt werden. Im folgenden Beitrag wird die Ionenstrahl- und Plasmaätztechnik in ihren Prinzipien und ihrer praktischen Anwendung dargelegt.

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Application and analytical problems of ion beam etching and plasma etching in structuring of electronic devices

Summary The manufacturing of fine line geometries in electronic circuits requires new technologies. This paper describes principles and practical applications of ion milling and plasma etching.

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Für anregende und hilfreiche Beiträge in einer Reihe von Erörterungen danken die Autoren Herrn Gerhard Lässing und Herrn Dr. Frank Stephany von der Firma AEG-Telefunken, Heilbronn.     

IonCCD Detector for Miniature Sector-Field Mass Spectrometer: Investigation of Peak Shape and Detector Surface Artifacts Induced by keV Ion Detection

A recently described ion charge coupled device detector IonCCD (Sinha and Wadsworth, Rev. Sci. Instrum. 76(2), 2005; Hadjar, J. Am. Soc. Mass Spectrom. 22(4), 612–624, 2011) is implemented in a miniature mass spectrometer of sector-field instrument type and Mattauch-Herzog (MH)-geometry (Rev. Sci. Instrum. 62(11), 2618–2620, 1991; Burgoyne, Hieftje and Hites J. Am. Soc. Mass Spectrom. 8(4), 307–318, 1997; Nishiguchi, Eur. J. Mass Spectrom. 14(1), 7–15, 2008) for simultaneous ion detection. In this article, we present first experimental evidence for the signature of energy loss the detected ion experiences in the detector material. The two energy loss processes involved at keV ion kinetic energies are electronic and nuclear stopping. Nuclear stopping is related to surface modification and thus damage of the IonCCD detector material. By application of the surface characterization techniques atomic force microscopy (AFM) and X-ray photoelectrons spectroscopy (XPS), we could show that the detector performance remains unaffected by ion impact for the parameter range observed in this study. Secondary electron emission from the (detector) surface is a feature typically related to electronic stopping. We show experimentally that the properties of the MH-mass spectrometer used in the experiments, in combination with the IonCCD, are ideally suited for observation of these stopping related secondary electrons, which manifest in reproducible artifacts in the mass spectra. The magnitude of the artifacts is found to increase linearly as a function of detected ion velocity. The experimental findings are in agreement with detailed modeling of the ion trajectories in the mass spectrometer. By comparison of experiment and simulation, we show that a detector bias retarding the ions or an increase of the B-field of the IonCCD can efficiently suppress the artifact, which is necessary for quantitative mass spectrometry.