UCL HEP Seminars
Seminars are generally held at 16:00 on Fridays in room A1 on the top floor of the Physics Department or — in the unlikely event of a global pandemic — online via Microsoft Teams or Zoom.
Please send suggestions for topics and/or speakers to Theresa Fruth and Andreas Korn.
: Matthew Mccullough (CERN)
The Higgs Boson Under a Microscope
What does the Higgs boson look like if you put it under a microscope? How does it move? Is it made up of smaller parts? Does it give itself mass? In this talk I will sketch a theoretical range of possible answers to these questions and, ultimately, how we might hope to answer them with the HL-LHC and future colliders.
: Lucian Harland-Lang (UCL)
The structure of the proton at approximate N3LO order: MSHT20aN3LO PDFs
As we move towards the era of high-luminosity LHC running, the precision in data and theory has reached an unprecedented level. As such an accurate and precise determination of proton structure, as encoded in parton distribution functions (PDFs), is an essential element of the LHC physics programme. An important aspect of PDF fitting that has recently received a great deal of attention is the question of how to correctly account for uncertainties due to missing higher orders in the perturbative calculation of observables that enter the PDF fit. In this talk I will present the results of a new study in this direction, namely the first global PDF fit at approximate N3LO order in the strong coupling. This applies a general formalism for the inclusion of theoretical uncertainties from missing higher orders into a PDF fit. I will demonstrate how using the currently available knowledge about N3LO theory, an order above the standard NNLO used in current PDF fits, can provide consistent, justifiable and explainable estimates for missing higher order uncertainties. Using this approach I will present the first approximate N3LO PDF fit with theoretical uncertainties, and analyse the differences between these N3LO PDFs and the standard NNLO PDFs.