The Large Hadron Collider (LHC) is at the heart of the worldwide effort to uncover the fundamental laws of physics, and has already discovered the Higgs boson. My research focusses on QCD aspects of LHC collisions, which is important for searches for new physics and stringent tests of the Standard Model carried out at the LHC. Much of my work focusses on jets, which are sprays of energetic collimated hadrons (see image). They are copiously produced at the LHC and play a crucial role in many analyses. To describe these intrinsically multi-scale processes, I use effective field theory.

Some of my contributions are:

• The N-Jettiness observable, which provides a theoretically clean definition of an event with N jets, and is employed in high precision (NNLO) calculations to treat infrared divergences. It is also used to quantify jet substructure at the LHC, for identifying hadronic decays of heavy particles (e.g. top quarks), which may prove crucial in uncovering a faint new physics signal. 
• The first precision calculation of  Higgs+0 jets, which involved the introduction of beam functions. Many LHC analyses bin events by the number of jets, to improve the signal sensitivity, which often dominates the theory uncertainty.
• A study of the potential of the electric charge of a jet to characterize a new physics signal, and its calculation. A generalization to a framework for calculating generic track-based observables.
• A rigorous QCD analysis of double parton scattering. This important component of collisions currently modeled by Monte Carlo simulations without a solid field-theoretic description.
• Multi-differential resummation techniques, reliably accounting for correlations between observables, hierarchies in jet angles and energies, etc.
• Exploring the use of the Winner-Take-All axis, which is insensitive to soft radiation, in the context of the jet shape, transverse momentum distributions of the constituents of the proton, and the azimuthal angle between a vector boson and jet in pp collisions.
• The effect of grooming away soft radiation on the jet energy and jet axis.

Some research that is a bit off the beaten path:

• Efficient counting of operators in effective field theories.
• Electroweak logarithms in inclusive cross sections.
• Higherorder gravitational lensing of the Cosmic Microwave Background using Feynman diagrams.

A full list of my publications can be viewed on Inspire.

After studying physics and mathematics at Utrecht University, I went on to obtain a PhD at MIT and was a postdoc at UC San Diego. I started as a junior faculty member at the UvA in 2013 and am also affiliated with the Nikhef theory group. I have ongoing collaborations with colleagues at various institutions, including MIT, DESY, Berkeley, CERN, SLAC, University of Vienna, Stoney Brook, Complutense Madrid and Zheijang University.

When I am not doing physics, I enjoy running, reading, traveling and of course spending time with my lovely wife and children.

Research group

• Uri Cohen (master student)
• Max Jaarsma (PhD student)
• Rudi Rahn (postdoc)
• Solange Schrijnder van Velzen (PhD student)
• Michiel Veen (PhD student)

Grants

• SPARC (2019-2021)
• NWO Projectruimte (2018-2022)
• ERC Starting Grant (2016-2021)
• MISTI Global Seed Fund (2015-2016)
• Veni (Lisa Zeune, 2015-2017)
• Marie Curie Fellowship (2013-2015)