Negative pion absorption at rest in "3He

Available from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Photoproduction of W boson at HERA: QCD corrections

W bosons can be produced in the channels e"#+-#p #-># W"#+-# + X at HERA thus allowing to probe for anomalous trilinear couplings among the gauge bosons. We discuss the next-to-leading order (NLO) QCD corrections to the photoproduction of W bosons with finite transverse momentum at HERA. The higher-order QCD corrections reduce the factorization scale dependence significantly and modify the leading-order (LO) cross sections by #+-#O(10%). (orig.)Available from TIB Hannover: RA 2999(02-035) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Is YbAs a heavy Fermion system

Using parameters extracted from a tight binding fit to an ab initio band structure, the specific heat anomaly observed in YbAs around 5 K is computed within the infinite U limit of the degenerate Anderson impurity model. Applying the renormalization procedure derived in variational treatments of the periodic Anderson model, a quasiparticle Fermi surface with strong nesting features and small mass enhancements is obtained. The results suggest that YbAs is not a classical'' heavy Fermion system. 28 refs., 3 figs., 1 tab

Photonic and QCD radiative corrections to Higgs-Boson production in #mu#"+ #mu#"- #->#f anti f

The photonic and QCD radiative corrections at next-to-leading order are calculated for fermion-pair production at muon colliders, maintaining the full mass dependence and helicity information of the muons and the produced fermions. Higher-order effects of initial-state radiation are included at the leading logarithmic level. In the calculation particular attention is paid to the issue of gauge invariance in the vicinity of resonances. The most important corrections are presented in analytical form. The detailed numerical discussion concentrates on the corrections to the (s-channel) Higgs-boson resonances in the Standard Model and its minimal supersymmetric extension. The results show that photonic initial- and QCD final-state corrections are very important in a precision study of Higgs resonances, but that (photonic) initial-final interferences are widely suppressed and only modify the non-resonant background. (orig.)Available from TIB Hannover: RA 2999(02-24) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Proceedings of the 4th MEGAPIE (MEGAwatt PIlot Experiments) technical review meeting

The fourth technical review meeting of the MEGAwatt PIlot Experiment (MEGAPIE) took place on 18-19 March, 2003 in Paris, in coincidence with the finalisation of the detailed design and the launching of the manufacturing phase (phase 5) of the project. The present volume contains the proceedings of this technical review meeting. The 36 contributions presented at the meeting, coming from Europe, USA, Japan and Korea, pointed out once more the international frame of the initiative, which is supported by six European research institutions (PSI, CEA, FZK, CNRS, ENEA, SCK), by JAERI (Japan), DOE (USA) and KAERI (Korea). The design of the Ancillary systems (Heat Removal System (HRS)), Cover Gas System (CGS), Liquid Metal Fill and Drain (F and D) System and Insulating Gas System (IGS) is also progressing. In particular the reference solution for the CGS is to periodically drain the gas in a decay tank. Safety and licensing issues were also addressed. Examples are the focused beam transient and the thermal shock transient. For both cases CFD calculations and stress analysis were performed. In the frame of the thermal hydraulic and structural mechanics task, a large amount of CFD calculations and stress analysis have been performed according to the needs expressed by the designers. At the meeting the following topics were presented: (a) RELAP 5 Analysis of the MEGAPIE target thermal hydraulics in steady state and transient conditions; (b) CFD simulation on the heat deposition distribution in the target; (c) Stress analysis of the liquid metal container under normal operating conditions; (d) the HYTAS water experiment, performed to investigate the cooling characteristics of the MEGAPIE beam window and the 3D-CFD simulations associated to the experiment; (e) the LBE KILOPIE and Heated Jet experiments, both under preparation; The Neutronics and Nuclear Assessment task group has performed detailed benchmark exercises and a compilation was produced. During the meeting it was agreed to the use MCNPX and FLUKA codes as reference tools for the project. Materials radiation damage task group has produced data on the mechanical properties of T91 steel at high temperature. These data were used for the safety analysis. In addition, an attempt was made to estimate the window lifetime using DBTT as a criterion. Compatibility tests on bare and welded T91 steel were performed in the frame of the solid - liquid interface task. Tests were performed at the laboratories of different associations, and a comprehensive compilation of the results seems to be mandatory. Progress in the LISOR experiments was shown. In fact a successful assembling and disassembling of the LISOR test section has been shown. In addition, tensile test on T91 exposed for 24 h at 300 C and irradiated for one hour did show ductile fracture mode. (orig.)SIGLEAvailable from TIB Hannover: ZA5141(6876) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Testing coupling relations in SUSY-QCD at a linear collider

Supersymmetry predicts that gauge couplings are equal to the corresponding gaugino-sfermion-fermion Yukawa couplings. This prediction can be tested for the QCD sector of the MSSM by studying the processes e"+e"- #-># squark+antisquark+gluon and e"+e"- #-># squark+antiquark+gluino at a future linear collider. We present results for these processes at next-to-leading order in #alpha#_s in the framework of the MSSM. We find sizable SUSY-QCD corrections. The renormalization scale dependence is significantly reduced at next-to-leading order. (orig.)SIGLEAvailable from TIB Hannover: RA 2999(02-097) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Verhalten einer geschaedigten Rohrleitung bei simuliertem Kuehlmittelverlust-Stoerfall mit hoher Druckstosslast. Quick Look Report. Versuch: E31.3

Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

A possible design for the NLC e sup + source

The Next Linear Collider (NLC) currently under investigation at SLAC requires a positron source with a flux of about 8.6 {times} 10{sup 13} particles per second, 14.4 times more than the SLC source. Based on the SLC experience, a source for NLC is proposed that can be realized with present accelerator technology. It consists of a 7 GeV S-band electron linac, a solid moving target, a 1.8 GeV L-band positron accelerator and a pre-damping ring with a large acceptance. The pre-damping ring performs positron accumulation and the matching of the positron source emittance to the NLC main damping ring acceptance. The scheme and parameters of the NLC positron source are given and the expected source performance is computed

SOPRO 2004 International workshop on sorption processes at oxide and carbonate mineral water interfaces

SOPRO 2004 is the fourth meeting in the series ''Karssruher Geochemical Workshops''. The first workshop, held in 1997 at the Forschungszentrum Karlsruhe, was entitled ''Geochemical modelling - radio toxic and chemical toxic substances in natural aquatic systems''. The second meeting was held in 1999 in Speyer focusing on ''Mineral/water interactions close to equilibrium''. The third workshop, held in 2002 in Karlsruhe, dealt with ''Modelling of coupled transport reaction processes''. SOPRO 2004 is intended to deal with sorption processes. These are for example relevant for retention of radionuclides migrating from nuclear waste repositories. General focus will be on fundamental studies from an experimental and theoretical point of view. The intention of SOPRO 2004 is to serve as a possibility to discuss the state of the art and our understanding of sorption processes at mineral water interfaces. Focus will be on oxide and carbonate minerals. The workshop intends to cover a broad range of experimental techniques (classical chemistry studies, surface spectroscopy), modeling aspects (such as surface complexation modeling), theoretical approaches (quantum chemistry) and the synthesis of results in data bases. The present report includes extended abstracts of the contributions presented at SOPRO 2004. (orig.)Available from TIB Hannover: ZA 5141(6986) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

TRePro 2002 - modelling of coupled transport reaction processes

TRePRo 2002 is the third meeting in the series of the Karlsruhe Geochemical Workshops. The first workshop was held in 1997 at the Forschungszentrum Karlsruhe. Its main topic was 'Geochemical Modelling - Radio Toxic and Chemical Toxic Substances in Natural Aquatic Systems'. The second workshop was held in 1999 in Speyer focusing on 'Mineral / Water Interactions Close to Equilibrium'. The present workshop was jointly organized by Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe (FZK-INE) and Labor fuer Endlagersicherheit, Paul Scherrer Institut (PSI-LES). This book of abstracts contains the contributions presented at TRePro 2002 held at the Forschungszentrum Karlsruhe, March 20-21, 2002. The organizing committee thanks all the authors for their efforts to prepare their extended abstracts in advance of the workshop. Moreover, we would like to thank the numerous persons behind the scenes who contributed in whatever way to the workshop. Especially, the support by FZK-INE director Prof. J.-I. Kim and PSI-LES director Prof. J. Hadermann is acknowledged. Special thanks are also due to Mrs. G. Endress for her administrative assistance. (orig.)Available from TIB Hannover: ZA 5141(6721) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman