scholarly journals Heavy-quark hadroproduction in k T -factorization approach with unintegrated gluon distributions

2006 ◽  
Vol 69 (2) ◽  
pp. 314-327 ◽  
Author(s):  
Yu. M. Shabelski ◽  
A. G. Shuvaev
Keyword(s):  
Heavy Quark ◽  
Unintegrated Gluon ◽  
Factorization Approach ◽  
Gluon Distributions

scholarly journals CHARMED MESON PRODUCTION IN PROTON–(ANTI)PROTON COLLISIONS

2007 ◽  
Vol 22 (02n03) ◽  
pp. 555-560
Author(s):  
MARTA ŁUSZCZAK ◽  
ANTONI SZCZUREK
Keyword(s):  
Heavy Quark ◽  
Meson Production ◽  
Experimental Results ◽  
Charmed Meson ◽  
Matrix Elements ◽  
Unintegrated Gluon ◽  
Proton Collisions ◽  
Shell Matrix ◽  
Gluon Distributions

We discuss and compare different approaches to include gluon transverse momenta for heavy quark-antiquark pair and meson production. The results are illustrated with the help of different unintegrated gluon distributions (UGDF) from the literature. We compare results obtained with on-shell and off-shell matrix elements and kinematics. The results are compared with recent experimental results of the CDF collaboration.

scholarly journals HEAVY QUARK PHOTOPRODUCTION IN THE SEMIHARD QCD APPROACH AND THE UNINTEGRATED GLUON DISTRIBUTION

2000 ◽  
Vol 15 (28) ◽  
pp. 1727-1738 ◽  
Author(s):  
A. V. LIPATOV ◽  
V. A. SALEEV ◽  
N. P. ZOTOV
Keyword(s):  
Experimental Data ◽  
Total Cross Section ◽  
Heavy Quark ◽  
Cross Section ◽  
Gluon Distribution ◽  
Unintegrated Gluon ◽  
Gluon Distributions ◽  
Theoretical Results

Processes of heavy quark photoproduction at HERA energies are considered using the semihard (k⊥ factorization) QCD approach with emphasis of the BFKL dynamics of gluon distributions. We investigate the dependences of the total cross-section of heavy quark photoproduction and also the pT distribution on different forms of the unintegrated gluon distribution. We present a comparison of the theoretical results with available H1 and ZEUS experimental data for charm and beauty photoproductions.

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.

PHOTOPRODUCTION OF HEAVY QUARKS AS A TOOL FOR INVESTIGATION OF THE SPIN-DEPENDENT GLUON DISTRIBUTIONS

1993 ◽  
Vol 08 (09) ◽  
pp. 1603-1612 ◽  
Author(s):  
S.I. ALEKHIN ◽  
V.I. BORODULIN ◽  
S.F. SULTANOV
Keyword(s):  
Heavy Quark ◽  
Heavy Quarks ◽  
Heavy Quark Production ◽  
Fixed Target ◽  
Polarization Asymmetry ◽  
Quark Production ◽  
Gluon Distributions ◽  
Polarized Gluon

The possibility for measuring polarized gluon distributions in the process of heavy quark production in the scattering of real photons off polarized fixed target has been considered. The estimates of γ-beam intensities required to determine the polarization asymmetry have been made.

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 ON THE UNDERSTANDING AND USE OF "UNINTEGRATED" PARTON DISTRIBUTIONS IN SMALL-X QCD

2011 ◽  
Vol 04 ◽  
pp. 74-84 ◽  
Author(s):  
EMIL AVSAR
Keyword(s):  
Unintegrated Gluon ◽  
Parton Distributions ◽  
Small X ◽  
Gluon Distributions

We review and discuss the use of TMD, or "unintegrated", gluon distributions in the domain of small-x physics. The definitions employed, and the hazards of the naive applications of the TMD factorization and the associated gluon distributions are discussed.

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