scholarly journals Photoproduction ofJ/ψmesons at high energies in the parton model andKT-factorization approach

2002 ◽  
Vol 65 (5) ◽  
Author(s):  
V. A. Saleev
Keyword(s):  
Parton Model ◽  
Factorization Approach ◽  
High Energies

scholarly journals Bottomonia production and polarization in the NRQCD with $$k_T$$-factorization. I: $$\Upsilon (3S)$$ and $$\chi _b(3P)$$ mesons

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
N. A. Abdulov ◽  
A. V. Lipatov
Keyword(s):  
Bound States ◽  
Spin Density Matrix ◽  
Unintegrated Gluon ◽  
Factorization Approach ◽  
Transverse Momentum Dependent ◽  
High Energies ◽  
Radiation Theory ◽  
Multipole Radiation ◽  
Shell Production ◽  
Good Agreement

Abstract The $$\Upsilon (3S)$$Υ(3S) production and polarization at high energies is studied in the framework of $$k_T$$kT-factorization approach. Our consideration is based on the non-relativistic QCD formalism for bound states formation and off-shell production amplitudes for hard partonic subprocesses. The transverse momentum dependent (TMD, or unintegrated) gluon densities in a proton were derived from the Ciafaloni-Catani-Fiorani-Marchesini (CCFM) evolution equation as well as from the Kimber–Martin–Ryskin (KMR) prescription. Treating the non-perturbative color octet transitions in terms of the multipole radiation theory and taking into account feed-down contributions from radiative $$\chi _b(3P)$$χb(3P) decays, we extract the corresponding non-perturbative matrix elements for $$\Upsilon (3S)$$Υ(3S) and $$\chi _b(3P)$$χb(3P) mesons from a combined fit to $$\Upsilon (3S)$$Υ(3S) transverse momenta distributions measured by the CMS and ATLAS Collaborations at the LHC energies $$\sqrt{s} = 7$$s=7 and 13 TeV and central rapidities. Then we apply the extracted values to describe the CDF and LHCb data on $$\Upsilon (3S)$$Υ(3S) production and to investigate the polarization parameters $$\lambda _\theta $$λθ, $$\lambda _\phi $$λϕ and $$\lambda _{\theta \phi }$$λθϕ, which determine the $$\Upsilon (3S)$$Υ(3S) spin density matrix. Our predictions have a good agreement with the currently available data within the theoretical and experimental uncertainties.

scholarly journals Intrinsic charm in the nucleon and charm production at large rapidities in collinear, hybrid and kT-factorization approaches

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Rafał Maciuła ◽  
Antoni Szczurek
Keyword(s):  
Transverse Momentum ◽  
High Energy ◽  
Charm Production ◽  
Leading Order ◽  
Collinear Factorization ◽  
Factorization Approach ◽  
High Energies ◽  
Neutrino Production ◽  
Intrinsic Charm ◽  
Gluon Distributions

Abstract We discuss the role of intrinsic charm (IC) in the nucleon for forward production of c-quark (or $$ \overline{c} $$ c ¯ -antiquark) in proton-proton collisions for low and high energies. The calculations are performed in collinear-factorization approach with on-shell partons, kT-factorization approach with off-shell partons as well as in a hybrid approach using collinear charm distributions and unintegrated (transverse momentum dependent) gluon distributions. For the collinear-factorization approach we use matrix elements for both massless and massive charm quarks/antiquarks. The distributions in rapidity and transverse momentum of charm quark/antiquark are shown for a few different models of IC. Forward charm production is dominated by gc-fusion processes. The IC contribution dominates over the standard pQCD (extrinsic) gg-fusion mechanism of $$ c\overline{c} $$ c c ¯ -pair production at large rapidities or Feynman-xF. We perform similar calculations within leading-order and next-to-leading order kT-factorization approach. The kT-factorization approach leads to much larger cross sections than the LO collinear approach. At high energies and large rapidities of c-quark or $$ \overline{c} $$ c ¯ -antiquark one tests gluon distributions at extremely small x. The IC contribution has important consequences for high-energy neutrino production in the Ice-Cube experiment and can be, to some extent, tested at the LHC by the SHIP and FASER experiments by studies of the ντ neutrino production.

scholarly journals Comparison of the k T-factorization approach and the QCD parton model for charm and beauty hadroproduction

2001 ◽  
Vol 64 (11) ◽  
pp. 1995-2005 ◽  
Author(s):  
M. G. Ryskin ◽  
Yu. M. Shabelski ◽  
A. G. Shuvaev
Keyword(s):  
Parton Model ◽  
Factorization Approach

HADRON PRODUCTION IN HIGH ENERGY LEPTON-NUCLEON AND LEPTON-NUCLEUS COLLISIONS

1988 ◽  
Vol 03 (09) ◽  
pp. 1997-2065 ◽  
Author(s):  
NORBERT SCHMITZ
Keyword(s):  
Meson Production ◽  
Parton Model ◽  
High Energy ◽  
Hadron Production ◽  
Model Data ◽  
High Energies ◽  
Quantum Numbers ◽  
Quark Parton Model ◽  
Fragmentation Functions ◽  
Bose Einstein

Recent experimental results on the production of hadrons in collisions of muons, neutrinos and antineutrinos with nucleons and nuclei at high energies are reviewed and discussed in the framework of the quark-parton model. Data are presented on the following topics: Multiplicities, fragmentation functions, transverse momenta and jet properties, azimuthal asymmetry, distribution of quantum numbers, production of strange and charmed particles, test of PCAC and shadowing, single meson production, and Bose-Einstein correlations.

scholarly journals New parton model for the soft interactions at high energies: The odderon

2020 ◽  
Vol 101 (9) ◽  
Author(s):  
E. Gotsman ◽  
E. Levin ◽  
I. Potashnikova
Keyword(s):  
Parton Model ◽  
High Energies ◽  
Soft Interactions
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