[ NIKHEF theory group ]

Purpose

To meet, discuss, collaborate, generate ideas, share expertise, in the context of the FOM programme "Higgs as Probe and Portal"

We hope to see you here!

Agenda Februari 16

Time: 10.00 - 17.00
  • 11.00 - 11.30, H320:

    Giulio Falcioni (Nikhef)
    High-order QCD corrections for Higgs (and more)

    Abstract: Precise theory predictions of signal and background processes at the LHC are needed to match precision of the experimental data and establish possible discrepancies with the Standard Model. From the theory point of view, it is necessary to include QCD radiative corrections beyond the leading order, which requires the use of very efficient computational techniques. This talk gives an overview on the methods based on the so-called $R^*$ operation, that have been used determine the Higgs boson decay rates to the fourth subleading order in QCD.



  • 13.00 - 13.30, H320
    Plot of the Month/Pie of the Month



  • 15.00 - 16.00, H320
    Student meeting/discussion:

    Sam Van Leuven (UVA)
    Exact solution of N=2 super Yang-Mills theories and generalized dualities in quantum field theory

    Abstract: I will give a pedagogical, non-technical overview of some exact results in N=2 super Yang-Mills theories. After introducing the field content, I will first discuss the work of Seiberg and Witten ('94) who solved for the low energy effective action of pure SU(2) Yang-Mills theory using relatively simple geometric methods. This will set the stage for more recent developments, such as the AGT correspondence, that unveil very surprising relations between four-dimensional gauge theories and two-dimensional conformal field theory.



  • 16.30 - 17.00, H320

    Marco Zaro (Nikhef)
    Subleading but large: The complete NLO corrections to 4-top production

    Abstract: I present the calculation of the complete-NLO predictions for four-top production in proton-proton collisions at 13 and 100 TeV. These predictions include all terms at order alpha_s^i alpha^j, with i+j=4,5, where alpha_s and alpha are respectively the strong and the electroweak coupling constant. Despite the suppression due to the coupling powers, the NLO contributions at order alpha alpha_s^4 and alpha^2 alpha_s^3 are individually large, but they cancel each other in an almost complete way. Such a delicate cancelation may be spoiled by BSM effects, like a non-standard top Yukawa coupling. While studies on these matters have only been carried out at LO accuracy, our results clearly show that NLO effects cannot be neglected and have to be considered at least in the estimate of theoretical uncertainties. Based on arXiv:1711.02116



  • 17.00 Borrel