Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements $V_{cb}$ and $V_{ub}$. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of $|V_{cb}|$ and $|V_{ub}|$ from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p

High-temperature deformation behavior of a gamma TiAl alloy-microstructural evolution and mechanisms

The present investigation was carried out in the context of the internal-variable theory of inelastic deformation and the dynamic-materials model (DMM), to shed light on the high-temperature deformation mechanisms in TiAl. A series of load-relaxation tests and tensile tests were conducted on a fine-grained duplex gamma TiAl alloy at temperatures ranging from 800 degreesC to 1050 degreesC. Results of the load-relaxation tests, in which the deformation took place at an infinitesimal level (epsilon congruent to 0.05), showed that the deformation behavior of the alloy was well described by the sum of dislocation-glide and dislocation-climb processes. To investigate the deformation behavior of the fine-grained duplex gamma TiAl alloy at a finite strain level, processing maps were constructed on the basis of a DMM. For this purpose, compression tests were carried out at temperatures ranging from 800 degreesC to 1250 degreesC using strain rates ranging from 10 to 10(-4)/s. Two domains were identified and characterized in the processing maps obtained at finite strain levels (0.2 and 0.6). One domain was found in the region of 980 degreesC and 10(-3)/s with a peak efficiency (maximum efficiency of power dissipation) of 48 pct and was identified as a domain of dynamic recrystallization (DRx) from microstructural observations. Another domain with a peak efficiency of 64 pct was located in the region of 1250 degreesC and 10(-4)/s and was considered to be a domain of superplasticity.ope

How To Find Charm in Nuclear Collisions at RHIC and LHC

Measurements of dilepton production from charm decay and Drell-Yan processes respectively probe the gluon and sea quark distributions in hadronic collisions. In nucleus-nucleus collisions, these hard scattering processes constitute a `background' to thermal contributions from the hot matter produced by the collision. To determine the magnitude and behavior of this background, we calculate the hard scattering contribution to dilepton production in nuclear collisions at RHIC and LHC at next to leading order in perturbative QCD. Invariant mass, rapidity and transverse momentum distributions are presented. We compare these results to optimistic hydrodynamic estimates of the thermal dilepton production. We find that charm production from hard scattering is by far the dominant contribution. Experiments therefore can measure the gluon distribution in the nuclear target and projectile and, consequently, can provide new information on gluon shadowing. We then illustrate how experimental cuts on the rapidity gap between the leptons can aid in reducing the charm background, thereby enhancing thermal information.Comment: 32 pages, latex, 19 figure

Physics with the KLOE-2 experiment at the upgraded DAϕ\phiNE

Investigation at a $\phi$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the $e^+ e^-$ physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.Comment: 60 pages, 41 figures; added affiliation for one of the authors; added reference to section

Die Reaktionen kritisch kranker Patienten unter Volumentherapie mit Hydroxyäthylstärke (6%HES 450/0,7)

Bei 31 kritisch kranken chirurgischen Patienten wurden hämodynamische und (O&lt;sub&gt;2&lt;/sub&gt;-Transport-Variable nach klinisch erforderlicher Volumentherapie mit 500ml 6% HES 450/0,7 bestimmt. Es ergaben sich signifikante Maximal-Anstiege des Herzindex (CI) von 3,5 ± 2,1 auf 4,4 ± 0,2 (1/min/m&lt;sup&gt;2&lt;/sup&gt;) und des Wedge-Drucks von 9,3 ± 0,7 auf 13,6 ± 0,8 (mmHg) und eine signifikante Verminderung des systemischen Widerstands (SVRI) von 2018 ± 128 auf 1641 ± 102 (dynsec/cm5 m&lt;sup&gt;2&lt;/sup&gt;). Auβerdem wurden maximale Anstiege der linksventrikulären Schlagarbeit (LVSWI) von 41 ± 3,1 auf 53 ± 3,2 (gm/m&lt;sup&gt;2&lt;/sup&gt;), der Sauerstoffver-fügbarkeit (DO&lt;sub&gt;2&lt;/sub&gt;) von 489 ± 24 auf 587 ± 29 (ml/min/m2) und des Sauerstoffverbrauchs (VO&lt;sub&gt;2&lt;/sub&gt;) von Ill ± 6 auf 130 ± 7 (ml/min/m2) während der maximalen Herzindex-Steigerung beobachtet. Darüber hinaus wurden die Reaktionen der Patienten (MAP, CI, VO&lt;sub&gt;2&lt;/sub&gt;) nach verschiedenen klinischen Gesichtspunkten wie OP-Zeitpunkt, Alter, Prognose, ARDS, Sepsis, Hyperdynamik und Blutvolumen aufgeschlüsselt.</jats:p

On the inclusion of dissipation on top of mean-field approaches

International audienc