TY  - JOUR
AU  - Cridge, T.
AU  - Harland-Lang, L. A.
AU  - Thorne, R. S.
TI  - A first determination of the strong coupling α<sub>S</sub> at approximate N<sup>3</sup>LO order in a global PDF fit
JO  - The European physical journal / C
VL  - 84
IS  - 10
SN  - 1434-6052
CY  - Heidelberg
PB  - Springer
M1  - PUBDB-2025-00271
M1  - arXiv:2404.02964
M1  - DESY-24-044
SP  - 1009
PY  - 2024
N1  - 22 pages, 12 figures, 1 table
AB  - We present the first determination of the value of the strong coupling via a simultaneous global fit of the proton parton distribution functions (PDFs) at approximate N<sup>3</sup>LO (aN<sup>3</sup>LO) order in QCD. This makes use of the MSHT global PDF fitting framework, and in particular the recent theoretical advances t l;;mhat allow a PDF fit to now be performed at this order. The value of the strong coupling is found to be α<sub>S</sub>(M<sub>Z</sub><sup>2</sup>)(aN<sup>3</sup>LO) = 0.1170 ±0.0016. This is in excellent agreement with the NNLO value of  α<sub>S</sub>(M<sub>Z</sub><sup>2</sup>)(NNLO) = 0.1171 ±0.0014, indicating that good perturbative convergence has been found. The resulting uncertainties, calculated using the MSHT dynamic tolerance procedure, are somewhat larger, but more accurate, at aN<sup>3</sup>LO, due to the missing higher order theoretical uncertainties that are included at this order, but not at NNLO. We in addition present a detailed breakdown of the individual dataset sensitivity to the value of the strong coupling, with special focus on the impact of fitting dijet rather than inclusive jet data. This choice is found to have a non-negligible impact, but with overall good consistency found, especially at aN<sup>3</sup>LO.
KW  - parton: distribution function (INSPIRE)
KW  - strong interaction: coupling constant (INSPIRE)
KW  - higher-order: 3 (INSPIRE)
KW  - dijet (INSPIRE)
KW  - quantum chromodynamics: perturbation theory (INSPIRE)
KW  - sensitivity (INSPIRE)
KW  - statistical analysis (INSPIRE)
KW  - data analysis method (INSPIRE)
LB  - PUB:(DE-HGF)16
C6  - 39385798
UR  - <Go to ISI:>//WOS:001330673600013
DO  - DOI:10.1140/epjc/s10052-024-13320-5
UR  - https://bib-pubdb1.desy.de/record/622233
ER  -