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Production of forward heavy-flavor dijets at the LHCb within the kT -factorization approach

Maciuła, Rafał ; Pasechnik, Roman LU and Szczurek, Antoni (2022) In Physical Review D 106(5).
Abstract

We calculate differential cross sections for cc¯- and bb¯-dijet production in pp scattering at s=13 TeV in the kT-factorization and hybrid approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in the transverse momentum and pseudorapidity of the leading jet, the rapidity difference between the jets and the dijet invariant mass. Our results are compared to recent LHCb data on forward production of heavy-flavor dijets, measured recently for the first time individually for both charm and bottom flavors. We find that an agreement between the predictions and the data within the full kT factorization is strongly related to the modeling of the large-x behavior of the gluon uPDFs, which is... (More)

We calculate differential cross sections for cc¯- and bb¯-dijet production in pp scattering at s=13 TeV in the kT-factorization and hybrid approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in the transverse momentum and pseudorapidity of the leading jet, the rapidity difference between the jets and the dijet invariant mass. Our results are compared to recent LHCb data on forward production of heavy-flavor dijets, measured recently for the first time individually for both charm and bottom flavors. We find that an agreement between the predictions and the data within the full kT factorization is strongly related to the modeling of the large-x behavior of the gluon uPDFs, which is usually not well constrained. The problem may be avoided following the hybrid-factorization approach. Then, we obtain a good description of the measured distributions with the parton-branching, Kimber-Martin-Ryskin, Kutak-Sapeta, and Jung setA0 models for the gluon uPDF. We also calculate differential distributions for the ratio of the cc¯ and bb¯ cross sections. In all cases we obtain a ratio close to 1, which is caused by the condition on the minimal jet transverse momentum (pTjet>20 GeV) introduced in the experiment, that makes the role of the heavy-quark mass almost negligible. The LHCb experimental ratio seems a bit larger than the theoretical predictions. We discuss potentially important for the ratio effect of c- or b-quark gluon radiative corrections related to emission outside of the jet cone. The found effect seems rather small. A more refined calculation requires full simulation of c and b jets, which goes beyond of the scope of this paper.

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author
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organization
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type
Contribution to journal
publication status
published
subject
in
Physical Review D
volume
106
issue
5
article number
054018
publisher
American Physical Society
external identifiers
  • scopus:85139033496
ISSN
2470-0010
DOI
10.1103/PhysRevD.106.054018
language
English
LU publication?
yes
id
e310701a-c1f2-413c-996f-f652a8539984
date added to LUP
2022-12-12 10:51:00
date last changed
2024-04-18 16:14:49
@article{e310701a-c1f2-413c-996f-f652a8539984,
  abstract     = {{<p>We calculate differential cross sections for cc¯- and bb¯-dijet production in pp scattering at s=13 TeV in the kT-factorization and hybrid approaches with different unintegrated parton distribution functions (uPDFs). We present distributions in the transverse momentum and pseudorapidity of the leading jet, the rapidity difference between the jets and the dijet invariant mass. Our results are compared to recent LHCb data on forward production of heavy-flavor dijets, measured recently for the first time individually for both charm and bottom flavors. We find that an agreement between the predictions and the data within the full kT factorization is strongly related to the modeling of the large-x behavior of the gluon uPDFs, which is usually not well constrained. The problem may be avoided following the hybrid-factorization approach. Then, we obtain a good description of the measured distributions with the parton-branching, Kimber-Martin-Ryskin, Kutak-Sapeta, and Jung setA0 models for the gluon uPDF. We also calculate differential distributions for the ratio of the cc¯ and bb¯ cross sections. In all cases we obtain a ratio close to 1, which is caused by the condition on the minimal jet transverse momentum (pTjet&gt;20 GeV) introduced in the experiment, that makes the role of the heavy-quark mass almost negligible. The LHCb experimental ratio seems a bit larger than the theoretical predictions. We discuss potentially important for the ratio effect of c- or b-quark gluon radiative corrections related to emission outside of the jet cone. The found effect seems rather small. A more refined calculation requires full simulation of c and b jets, which goes beyond of the scope of this paper.</p>}},
  author       = {{Maciuła, Rafał and Pasechnik, Roman and Szczurek, Antoni}},
  issn         = {{2470-0010}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{5}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review D}},
  title        = {{Production of forward heavy-flavor dijets at the LHCb within the kT -factorization approach}},
  url          = {{http://dx.doi.org/10.1103/PhysRevD.106.054018}},
  doi          = {{10.1103/PhysRevD.106.054018}},
  volume       = {{106}},
  year         = {{2022}},
}