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Large NLO corrections in tt¯ W± and tt¯ tt¯ hadroproduction from supposedly subleading EW contributions

Frederix, Rikkert LU orcid ; Pagani, Davide and Zaro, Marco (2018) In Journal of High Energy Physics 2018(2).
Abstract

We calculate the complete-NLO predictions for tt¯ W± and tt¯ tt¯ production in proton-proton collisions at 13 and 100 TeV. All the non-vanishing contributions of O(αsiαj) with i + j = 3, 4 for tt¯ W± and i + j = 4, 5 for tt¯ tt¯ are evaluated without any approximation. For tt¯ W± we find that, due to the presence of tW → tW scattering, at 13(100) TeV the O(αsα3) contribution is about 12(70)% of the LO, i.e., it is larger than the so-called NLO EW corrections (the O(αs2α2) terms) and has opposite sign. In the case of tt¯ tt¯ production, large contributions from electroweak tt → tt scattering are already present at LO in the O(αs3α) and O(αs2α2) terms. For the same reason we find that... (More)

We calculate the complete-NLO predictions for tt¯ W± and tt¯ tt¯ production in proton-proton collisions at 13 and 100 TeV. All the non-vanishing contributions of O(αsiαj) with i + j = 3, 4 for tt¯ W± and i + j = 4, 5 for tt¯ tt¯ are evaluated without any approximation. For tt¯ W± we find that, due to the presence of tW → tW scattering, at 13(100) TeV the O(αsα3) contribution is about 12(70)% of the LO, i.e., it is larger than the so-called NLO EW corrections (the O(αs2α2) terms) and has opposite sign. In the case of tt¯ tt¯ production, large contributions from electroweak tt → tt scattering are already present at LO in the O(αs3α) and O(αs2α2) terms. For the same reason we find that both NLO terms of O(αs4α), i.e., the NLO EW corrections, and O(αs3α2) are large (±15% of the LO) and their relative contributions strongly depend on the values of the renormalisation and factorisation scales. However, large accidental cancellations are present (away from the threshold region) between these two contributions. Moreover, the NLO corrections strongly depend on the kinematics and are particularly large at the threshold, where even the relative contribution from O(αs2α3) terms amounts to tens of percents.

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author
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publishing date
type
Contribution to journal
publication status
published
subject
keywords
NLO Computations, QCD Phenomenology
in
Journal of High Energy Physics
volume
2018
issue
2
article number
31
publisher
Springer
external identifiers
  • scopus:85041809542
ISSN
1029-8479
DOI
10.1007/JHEP02(2018)031
language
English
LU publication?
no
id
83fc8352-1f42-4bc4-b053-215d127c5a1b
date added to LUP
2019-05-28 15:54:06
date last changed
2022-04-26 00:52:56
@article{83fc8352-1f42-4bc4-b053-215d127c5a1b,
  abstract     = {{<p>We calculate the complete-NLO predictions for tt¯ W<sup>±</sup> and tt¯ tt¯ production in proton-proton collisions at 13 and 100 TeV. All the non-vanishing contributions of O(αsiαj) with i + j = 3, 4 for tt¯ W<sup>±</sup> and i + j = 4, 5 for tt¯ tt¯ are evaluated without any approximation. For tt¯ W<sup>±</sup> we find that, due to the presence of tW → tW scattering, at 13(100) TeV the O(α<sub>s</sub>α<sup>3</sup>) contribution is about 12(70)% of the LO, i.e., it is larger than the so-called NLO EW corrections (the O(αs2α2) terms) and has opposite sign. In the case of tt¯ tt¯ production, large contributions from electroweak tt → tt scattering are already present at LO in the O(αs3α) and O(αs2α2) terms. For the same reason we find that both NLO terms of O(αs4α), i.e., the NLO EW corrections, and O(αs3α2) are large (±15% of the LO) and their relative contributions strongly depend on the values of the renormalisation and factorisation scales. However, large accidental cancellations are present (away from the threshold region) between these two contributions. Moreover, the NLO corrections strongly depend on the kinematics and are particularly large at the threshold, where even the relative contribution from O(αs2α3) terms amounts to tens of percents.</p>}},
  author       = {{Frederix, Rikkert and Pagani, Davide and Zaro, Marco}},
  issn         = {{1029-8479}},
  keywords     = {{NLO Computations; QCD Phenomenology}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{Springer}},
  series       = {{Journal of High Energy Physics}},
  title        = {{Large NLO corrections in tt¯ W<sup>±</sup> and tt¯ tt¯ hadroproduction from supposedly subleading EW contributions}},
  url          = {{http://dx.doi.org/10.1007/JHEP02(2018)031}},
  doi          = {{10.1007/JHEP02(2018)031}},
  volume       = {{2018}},
  year         = {{2018}},
}