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[en] Measurements of M_J-state resolved Stern-Gerlach deflection patterns for the ³P₂ states of noble gas metastable atoms in supersonic beams are analyzed using a modification of the method originally worked out by Otto Stern. Velocity distribution breadth and beam collimation required to resolve the M_J states are explored, and the modeling is improved by including variation in the field gradient along the deflected atomic trajectories. (orig.)

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[en] Results on spectroscopy of excited b-hadrons from the LEP experiments are reviewed. (orig.)

[en] Using laser-state-selected metastable neon combined with mass spectrometric product detection in a crossed supersonic beam experiment, we have found a marked dependence of the fraction of associative ionization in Ne*+Ar Penning ionization on the initial fine-structure state of Ne*. Ne*(³P₀) produces more NeAr⁺ than ³P₂ relative to the total ionization cross section by amounts ranging from 33% more at E = 1.5 kcal/mol to 72% at E = 4.5

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[en] A new inclusive secondary vertex reconstruction algorithm which exploits the topological structure of weak b- and c-hadron decays inside jets is presented. The primary goal is the application to b-jet tagging. The fragmentation of a b-quark results in a decay chain composed of a secondary vertex from the weakly decaying b-hadron and typically one or more tertiary vertices from c-hadron decays. The decay lengths and charged particle multiplicities involved in these decays, as well as the instrumental resolution, do not allow to separately reconstruct and resolve these vertices efficiently using conventional secondary vertexing algorithms based on the assumption of a common geometrical vertex. These difficulties are partially overcome in the algorithm presented in this paper, that is based on the hypothesis that the primary event vertex and the vertices of the weak b- and c-hadron decays lie on the same line, the flight direction of the b-hadron. The algorithm provides detailed information on the topology of the decay cascade. The algorithm based on this hypothesis is implemented mathematically as an extension of the Kalman Filter formalism for vertex reconstruction and technically as a set of flexible software modules integrated in the ATLAS software framework Athena, which make use of the existing Event Data Model for vertex reconstruction and b-tagging. The application of the algorithm to b-jet tagging is shown

[en] Relative ionization cross sections for the title systems with articulation of all product ion channels have been measured in the collision energy range 1.5--4.0 kcal/mol using crossed supersonic molecular beams; the H₂ results have been extended down to 0.5 kcal/mol by the use of a 10% H₂/Ar seeded beam. The data are interpreted with a microscopic two-step model that assumes ionization near the turning point in the excited state, a centrifugal barrier criterion for ionic complex formation, and statistical partitioning of flux among the possible ionic products, i.e., phase-space theory. A full statistical calculation underestimates the amount of rearrangement ionization He*+H₂→HeH⁺+H+e^- by a factor of 2, but one which excludes antiparallel coupling of orbital and rotational angular momenta in the H⁺₂ channel is in better accord with the data. A substantial isotope effect favoring HeD⁺ over HeH⁺ in the HD reactions by a factor of 1.9 +- 0.2 is well represented by the model