PION AND KAON PRODUCTION IN E(-) AND EP COLLISIONS AT NEXT-TO-LEADINGORDER()E()

Citation
J. Binnewies et al., PION AND KAON PRODUCTION IN E(-) AND EP COLLISIONS AT NEXT-TO-LEADINGORDER()E(), Physical review. D. Particles and fields, 52(9), 1995, pp. 4947-4960
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Particles & Fields
ISSN journal
0556-2821
Volume
52
Issue
9
Year of publication
1995
Pages
4947 - 4960
Database
ISI
SICI code
0556-2821(1995)52:9<4947:PAKPIE>2.0.ZU;2-7
Abstract
We present new sets of fragmentation functions for charged pions and k aons, both at leading and next-to-leading order. They are fitted to da ta on inclusive charged-hadron production in e(+)e(-) annihilation tak en by the TPC Collaboration at SLAG PEP (root s = 29 GeV) and to simil ar data by ALEPH at CERN LEP, who discriminated between events with ch arm, bottom, and light-flavor fragmentation in their charged-hadron sa mple. In contrast with our previous analysis, where we only distinguis hed between valence-quark, sea-quark, and gluon fragmentation, we are now able to treat all partons independently and to properly incorporat e the charm and bottom thresholds. Because of the sizable energy gap b etween PEP and LEP, we are sensitive to the scaling violation in the f ragmentation process, which allows us to extract a value for the asymp totic scale parameter of QCD, h. Recent data on inclusive charged-hadr on production in tagged three-jet events by OPAL and similar data for longitudinal electron polarization by ALEPH allow us to pin down the g luon fragmentation functions. Our new fragmentation functions lead to an excellent description of a multitude of other e(+)e(-) data on incl usive charged-hadron production, ranging from root s = 5.2 GeV to LEP energy: In addition, they agree nicely with the transverse-momentum sp ectra of single charged hadrons measured by H1 and ZEUS in photoproduc tion at the DESY ep collider HERA, which represents a nontrivial check of the factorization theorem of the QCD-improved parton model. In thi s comparison, we also find first evidence for the interplay between th e direct- and resolved-photon mechanisms and for the existence of a gl uon density inside the photon.