4,258 research outputs found
The Impact of Measurements at Intermediate Energies on the Parameters of the Standard Model
We discuss the impact of precision measurements of in the center-of-mass range between 3 and 12 GeV, including
improvements in the electronic widths of the narrow charmonium and bottonium
resonances, on the determination of parameters of the Standard Model. In
particular we discuss the impact of potential improvements on the extraction of
the strong coupling constant , on the evaluation of the hadronic
contributions to the electromagnetic coupling , and the
determination of the charm and bottom quark masses.Comment: 8 page
Comment on the Average Momentum of Top Quarks in the Threshold Region
The behavior of the momentum distribution of top quarks in the threshold
region is investigated. The qualitative behavior, in particular the dependence
of the average momentum on the strong coupling constant can be understood from
analytical calculations for the Coulomb potential. Ambiguities in the relation
between the excitation curve and the top mass are addressed.Comment: Univ. of Karlsruhe preprint TTP93-31, LaTeX, 6 pages including two
figures (uses epsf) appended as uuencoded postscript fil
QCD Corrections to Toponium Production at Hadron Colliders
Toponium production at future hadron colliders is investigated. Perturbative
QCD corrections to the production cross section for gluon fusion are calculated
as well as the contributions from gluon-quark and quark-antiquark collisions to
the total cross section. The dependence on the renormalization and
factorization scales and on the choice of the parton distribution functions is
explored. QCD corrections to the branching ratio of into
are included and the two-loop QCD potential is used to predict
the wave function at the origin. The branching ratio of into , , and is compared with the channel.Comment: 16 pages (latex) 9 figures (postscript) available upon request,
TTP92-3
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