Constraining the top-quark mass within the global MSHT PDF fit

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2023-09, Vol.83 (9), p.805-17, Article 805
• Main Authors: Cridge, Thomas, Lim, Matthew A.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Coupling; Cross-sections; Datasets; Distribution (Probability theory); Distribution functions; Elementary Particles; Hadrons; Heavy Ions; Kinematics; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Pair production; Partons; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quarks; Regular Article - Theoretical Physics; String Theory
• ISSN: 1434-6052; 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-023-11961-6

We examine the ability of experimental measurements of top-quark pair production to constrain both the top-quark mass and the strong coupling within the global MSHT parton distribution function (PDF) fit. Specifically, we consider ATLAS and CMS measurements of differential distributions taken at a centre-of-mass energy of 8 TeV, as well as t t ¯ total cross section data taken at a variety of experiments, and compare to theoretical predictions including next-to-next-to-leading order corrections. We find that supplementing the global fit with this additional information results in relatively strong constraints on the top-quark mass, and is also able to bound the strong coupling in a limited fashion. Our final result is m t = 173.0 ± 0.6 GeV and is compatible with the world average pole mass extracted from cross section measurements of 172.5 ± 0.7 GeV by the Particle Data Group. We also study the effect of different top-quark masses on the gluon parton distribution function, finding changes at high x which nonetheless lie within the large PDF uncertainties in this region.