24 research outputs found
Formalism for dilepton production via virtual photon bremsstrahlung in hadronic reactions
We derive a set of new formulas for various distributions in dilepton
production via virtual photon bremsstrahlung from pseudoscalar mesons and
unpolarized spin-one-half fermions. These formulas correspond to the leading
and sub-leading terms in the Low-Burnett-Kroll expansion for real photon
bremsstrahlung. The relation of our leading-term formulas to previous works is
also shown. Existing formulas are examined in the light of Lorentz covariance
and gauge invariance. Numerical comparison is made in a simple example, where
an "exact" formula and real photon data exist. The results reveal large
discrepancies among different bremsstrahlung formulas. Of all the leading-term
bremsstrahlung formulas, the one derived in this work agrees best with the
exact formula. The issues of M_T-scaling and event generators are also
addressed.Comment: 37 pages, RevTeX, epsf.sty, 10 embedded figure
First measurements of hadronic decays of the Z boson
We have observed hadronic final states produced in the decays of Z bosons. In order to study the parton structure of these events, we compare the distributions in sphericity, thurst, aplanarity, and number of jets to the predictions of several QCD-based models and to data from lower energies. The data and models agree within the present statistical precision
Initial measurements of Z-boson resonance parameters in e+e- annihilation
We have measured the mass of the Z boson to be 91.11±0.23 GeV/c^2, and its width to be 1.61-0.43+0.60 GeV. If we constrain the visible width to its standard-model value, we find the partial width to invisible decay modes to be 0.62±0.23 GeV, corresponding to 3.8±1.4 neutrino species
Wie Management Reporting 2020 aussehen könnte
Die Erwartungen an Management Reporting sind hoch. Es soll immer effizienter und effektiver werden, dabei zugleich stark wachsende Datenmengen und neue komplexe Strukturen berücksichtigen. Unternehmen können auf diese Veränderungen mit unterschiedlichen Strategien reagieren. Drei Szenarien zeigen, wie das Management Reporting der Zukunft aussehen kann
Komplexität – Einführung in die Komplexitätsforschung und Herausforderungen für die Praxis
Targeting Multifunctional Proteins by Virtual Screening: Structurally Diverse Cytohesin Inhibitors with Differentiated Biological Functions
SEARCH FOR DIRECT gamma PRODUCTION AT LOW TRANSVERSE MOMENTUM IN 63-GeV p p COLLISIONS
We have searched for direct photons of low PT (≤1.0 GeV/c) at θc.m.=90° in pp collisions at √s =63 GeV. We used two independent methods: direct detection in NaI crystals and conversion to e+e− pairs. No signal is observed; the photon spectrum is well described by the decay of hadrons. The result is consistent with a direct low-PT photon signal reported at √s =12 GeV, but excludes a rapid growth of soft-photon production with √s