29,497 research outputs found
QCD Factorization for heavy quarkonium production at collider energies
In this talk, I briefly review several models of the heavy quarkonium
production at collider energies, and discuss the status of QCD factorization
for these production models.Comment: 7 pages, 12 figures, Talk presented at the Conference on Quark
Confinement and Hadron Spectrum VII, Ponta Delgada, Portugal, 2-7 September,
200
Preen Gland-Secreted Alkanols Enhance Male Attractiveness in Parrots
The skin glands are widely used in pheromone production throughout the vertebrate worlds. Growing evidences show that birds also have chemical communication, but the uropygial (also called preen or oil) glands, serving as only specialized skin glands of birds, have no sex pheromones characterized. Here, by combining GC-MS analysis and bioassay, we show with the budgerigar, Melopsittacus undulatus, that birds can used the preen gland-secreted volatiles (a blend of octadecanol, nonadecanol and eicosanol for male budgerigars) spread over body plumage when preening to convey sex information. Here, we first report the avian pheromones derived from the uropyginal gland and suggests that the gland has broader implications than previously known (e.g. plumage waterproofing and reflectance in sexual behaviour of birds
Collinear factorization for deep inelastic scattering structure functions at large Bjorken xB
We examine the uncertainty of perturbative QCD factorization for hadron
structure functions in deep inelastic scattering at a large value of the
Bjorken variable xB. We analyze the target mass correction to the structure
functions by using the collinear factorization approach in the momentum space.
We express the long distance physics of structure functions and the leading
target mass corrections in terms of parton distribution functions with the
standard operator definition. We compare our result with existing work on the
target mass correction. We also discuss the impact of a final-state jet
function on the extraction of parton distributions at large fractional momentum
x.Comment: 18 pages, 10 figures; discussion on baryon number conservation
clarifie
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