4 research outputs found

    Subleading Light-cone distributions functions in the decays Lambda(b) --> X(s) Gamma and Lambda(b) --> X(u) Lepton Anti-Nu

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    In this paper we investigate the subleading twist corrections to the photon energy spectrum in the decay Lambda_b -> X_s \gamma and to the lepton energy spectrum in Lambda_b -> X_u l \bar{\nu}. As a first step we rederive the matching coefficients of the subleading twist using a much simpler method. Parametrizing the matrix elements for Lambda_b and using reparametrization invariance, we show that the energy spectra close to the endpoints are given in terms of only a single universal function.Comment: LATEX,The complete paper is also available via the www at http://www-ttp.physik.uni-karlsruhe.de/Preprints/ . Discussion section improve

    Das Spektrum der hadronisch invarianten Masse in semileptonischen ZerfÀllen B X c lny

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    Das Spektrum der hadronisch invarianten Masse in semileptonischen ZerfĂ€llen <i>B &#8594; X<font size=-1><sub>c</sub></font>l&nu;</i> <br /> <br /> In der vorliegenden Arbeit wird das Spektrum der hadronisch invarianten Masse des inklusiven semileptonischen Zerfalls <i>B &#8594; X<font size=-1><sub>c</sub></font>l&nu;</i> prĂ€sentiert. Durch die Verwendung der Lichtkegelentwicklung ergibt die Berechnung ein glattes Spektrum, in dem zuverlĂ€ssig physikalische Schnitte platziert werden können. Diese Entwicklung stellt eine Operatorproduktentwicklung dar, welche der kinematischen Situation, in der die Zerfallsprodukte die maximale Energie erhalten, angepasst ist. Dabei wird berĂŒcksichtigt, dass der numerische Wert der invarianten Masse des c-Quarks von der gleichen GrĂ¶ĂŸenordnung ist wie der Entwicklungparameter. Der Verlauf des Spektrums wird durch Shapefunktionen beschrieben. Die Resultate stimmen mit publizierten Ergebnissen ĂŒberein, wenn die Shapefunktionen entwickelt bzw. die Masse des c-Quarks vernachlĂ€ssigt wird. Durch die genaue Kenntnis des Verlaufs des Spektrums können Momente in AbhĂ€ngigkeit von einem Cutoff berechnet werden. Ein Vergleich der ersten Momente des gesamten Spektrums mit experimentellen Daten zeigt eine gute Übereinstimmung. Die Ergebnisse dieser Arbeit werden die Ungenauigkeit von hadronischen Parametern verringern, die bei der Bestimmung von CKM-Matrixelementen benötigt werden. Dadurch wird eine prĂ€zise Analyse des UnitaritĂ€tsdreiecks möglich, die klĂ€rt, ob Diskrepanzen zwischen den theoretischen Vorhersagen und den experimentellen Daten existieren und wie die Theorie erweitert werden muss, damit die Effekte der neuen Physik exakt beschrieben werden.Das Spektrum der hadronisch invarianten Masse in semileptonischen ZerfĂ€llen <i>B &#8594; X<font size=-1><sub>c</sub></font>l&nu;</i> <br /> <br /> The dissertation at hand provides the spectrum of the hadronic invariant mass in the inclusive semileptonic decay <i>B &#8594; X<font size=-1><sub>c</sub></font>l&nu;</i>. The calculation leading to this result was carried out using the lightcone expansion, which is an operator product expansion that is adjusted to properly describe the kinematics if all decay products reach their maximum energy. This method guaranties a smooth shape for the complete spectrum, which can then be used to introduce physical cuts. Furthermore it was taken into account that the invariant mass of the c quark is of the same order as the expansion parameter. The spectrum is described by shape functions. By expanding these shape functions or by examining the limit m<sub>c</sub> &#8594; 0, known results are reproduced. The knowledge of the exact shape of the spectrum can be used to calculate moments with a cutoff. The first moments in terms of the whole spectrum are in good agreement with experimental data. The results of this work will enhance the precision of hadronic parameters that describe inclusive decays of B mesons. These parameters are used to extract CKM matrix elements from experimental data. A smaller uncertainty concerning these matrix elements will allow for a more accurate analysis of the unitarity triangle which can clarify if there are discrepancies between experimental data and theoretical predictions and how the theory has to be enlarged to incorporate the effects of new physics beyond the standard model

    Zinc-Imidazolate Films as an All-Dry Resist Technology

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    Motivated by the drawbacks of solution phase processing, an all-dry resist formation process is presented that utilizes amorphous zinc-imidazolate (aZnMIm) films deposited by atomic/molecular layer deposition (ALD/MLD), patterned with electron beam lithography (EBL), and developed by novel low temperature (120 °C) gas phase etching using 1,1,1,5,5,5-hexafluoroacetylacetone (hfacH) to achieve well-resolved 22 nm lines with a pitch of 30 nm. The effects of electron beam irradiation on the chemical structure and hfacH etch resistance of aZnMIm films are investigated, and it is found that electron irradiation degrades the 2-methylimidazolate ligands and transforms aZnMIm into a more dense material that is resistant to etching by hfacH and has a C:N:Zn ratio effectively identical to that of unmodified aZnMIm. These findings showcase the potential for aZnMIm films to function in a dry resist technology. Sensitivity, contrast, and critical dimensions of the patterns are determined to be 37 mC cm-2, 0.87, and 29 nm, respectively, for aZnMIm deposited on silicon substrates and patterned at 30 keV. This work introduces a new direction for solvent-free resist processing, offering the prospect of scalable, high-resolution patterning techniques for advanced semiconductor fabrication processes
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