Search results for "DESY HERA Stor"
showing 4 items of 4 documents
Heavy quarkonium: progress, puzzles, and opportunities
2011
A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flo…
Running of the Charm-Quark Mass from HERA Deep-Inelastic Scattering Data
2017
Physics letters / B 775, 233 - 238 (2017). doi:10.1016/j.physletb.2017.11.002
New Results on Charm Production at HERA
2014
The copious production of charm quarks at HERA yielded measure- ments of the charm contribution to the proton structure and of the charm mass and fragmentation parameters of charmed hadrons. Several measure- ments of charm production in deep inelastic scattering from the H1 and ZEUS collaborations as well as combined data are presented. They provide a powerful vindication of the form of the gluon density in the proton de- rived from scaling violations of inclusive deep inelastic scattering data. A QCD fit to the charm data leads to a measurement of the charm mass and provides precise predictions e.g. for W and Z production at the LHC. In ad- dition, charm fragmentation fractions in photopro…
Inclusive photoproduction of bottom quarks for low and medium p T in the general-mass variable-flavour-number scheme
2016
We present predictions for b-quark production in photoprodcution and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e+e- data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.