The Large Hadron Collider (LHC) is at the heart of the worldwide effort to uncover the fundamental laws of physics. After the highly successful Run 1, with as climax the Nobel prize winning discovery of the Higgs boson, the hunt for Beyond-the-Standard Model physics is about to resume at even higher energies. My research focusses on QCD aspects of LHC collisions. An introduction to why and how QCD is important for the LHC, is presented in my recent national seminar.

My main research themes are:

• Developing and studying observables that can be used to identify and characterize new physics.
• Improving theoretical predictions, e.g. for the extraction of Higgs couplings from data. 

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 techniques.

Some of my contributions are:

• The N-Jettiness observable, which provides a theoretically clean definition of an event with N jets. It is also successfully used as jet substructure at the LHC, to identify hadronic decays of heavy particles (e.g. top quarks), which could prove crucial in uncovering a faint new physics signal.
• The first precision calculation of Higgs+0 jets. Many LHC analyses bin events by the number of jets, to improve the signal sensitivity, which typically dominates the theory uncertainty.
• A precision calculation of the invariant mass spectrum of jets, an important benchmark observable.
• A study of LHC applications of the electric charge of a jet and its calculation.

• A rigorous QCD analysis of double parton scattering. This important component in Monte Carlo simulations of LHC events lacked a solid field-theoretic description.

A Two Jet Event - ATLAS Experiment © 2013 CERN

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 part of the Nikhef theory group. I have ongoing collaborations with colleagues at MIT, Harvard and DESY, whom I regularly visit.

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

Massachusetts Institute of Technology (from Prudential sky walk)

Sunset in California

Back in the Netherlands

Some recent talks:

• Jet Substructure at the LHC, Los Alamos seminar (Jan. 8, 2015) 
• QCD at the LHC, National seminar (Nov. 21, 2014)
• Dissecting Soft Radiation with Factorization, MPI@LHC 2014 (Nov. 4, 2014) 

Publications

Can also be viewed on Inspire.

1. P. Bartalini, D. Treleani, W. Waalewijn, et. al., Progress in Double Parton Scattering Studies, arXiv:1410.6664.
2. M. Procura, W. J. Waalewijn, and L. Zeune, Resummation of Double-Differential Cross Sections and Fully-Unintegrated Parton Distribution Functions, arXiv:1410.6483
3. A. J. Larkoski, J. Thaler, and W. J. Waalewijn, Gaining (Mutual) Information about Quark/Gluon Discrimination, arXiv:1408.3122.
4. M. Ritzmann and W. J. Waalewijn, Fragmentation in Jets at NNLO, Phys. Rev. D90 (2014) 054029.
5. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, Dissecting Soft Radiation with Factorization, arXiv:1405.6722.
6. E. E. Jenkins, A. V. Manohar, W. J. Waalewijn, and A. P. S. Yadav, Higher-Order Gravitational Lensing Reconstruction using Feynman Diagrams, JCAP 1409 (2014) 024.
7. E. E. Jenkins, A. V. Manohar, W. J. Waalewijn, and A. P. S. Yadav, Gravitational Lensing of the CMB: a Feynman Diagram Approach, Phys. Lett. B736 (2014) 6–10.
8. H.-M. Chang, M. Procura, J. Thaler, and W. J. Waalewijn, Calculating Track Thrust with Track Functions, Phys. Rev. D88 (2013) 034030.
9. H.-M. Chang, M. Procura, J. Thaler, and W. J. Waalewijn, Calculating Track-Based Observables for the LHC, Phys. Rev. Lett. 111 (2013) 102002.
10. T. T. Jouttenus, I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, Jet Mass Spectra in Higgs + One Jet at NNLL, Phys. Rev. D88 (2013) 054031.
11. H.-M. Chang, A. V. Manohar, and W. J. Waalewijn, Double Parton Correlations in the Bag Model, Phys. Rev. D87 (2013) 034009.
12. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, Combining Fixed-Order Helicity Amplitudes With Resummation Using SCET, PoS LL2012 (2012) 058.
13. W. J. Waalewijn, Calculating the Charge of a Jet, Phys. Rev. D86 (2012) 094030.
14. D. Krohn, T. Lin, M. D. Schwartz, and W. J. Waalewijn, Jet Charge at the LHC, Phys. Rev. Lett. 110 (2013) 212001.
15. T. T. Jouttenus, I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, The Soft Function for Exclusive N-Jet Production at Hadron Colliders, AIP Conf. Proc. 1441 (2012) 803–805.
16. A. Jain, M. Procura, B. Shotwell, and W. J. Waalewijn, Fragmentation with a Cut on Thrust: Predictions for B-factories, Phys. Rev. D87 (2013) 074013.
17. A. V. Manohar and W. J. Waalewijn, What is Double Parton Scattering?, Phys. Lett. B713 (2012) 196–201.
18. A. V. Manohar and W. J. Waalewijn, A QCD Analysis of Double Parton Scattering: Color Correlations, Interference Effects and Evolution, Phys. Rev. D85 (2012) 114009.
19. S. Dittmaier, C. Mariotti, G. Passarino, R. Tanaka, et. al., Handbook of LHC Higgs Cross Sections: 2. Differential Distributions, arXiv:1201.3084.
20. M. Procura and W. J. Waalewijn, Fragmentation in Jets: Cone and Threshold Effects, Phys. Rev. D85 (2012) 114041.
21. A. Jain, M. Procura, and W. J. Waalewijn, Fully-Unintegrated Parton Distribution and Fragmentation Functions at Perturbative kT , JHEP 1204 (2012) 132. 
22. T. T. Jouttenus, I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, The Soft Function for Exclusive N-Jet Production at Hadron Colliders, Phys. Rev. D83 (2011) 114030.
23. A. Jain, M. Procura, and W. J. Waalewijn, Parton Fragmentation within an Identified Jet at NNLL, JHEP 1105 (2011) 035.
24. C. F. Berger, C. Marcantonini, I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, Higgs Production with a Central Jet Veto at NNLL+NNLO, JHEP 1104 (2011) 092.
25. A. Fuhrer, A. V. Manohar, and W. J. Waalewijn, Electroweak radiative Corrections to Higgs Production via Vector Boson Fusion using Soft-Collinear Effective Theory, Phys. Rev. D84 (2011) 013007.
26. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, The Beam Thrust Cross Section for Drell-Yan at NNLL Order, Phys. Rev. Lett. 106 (2011) 032001.
27. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, N-Jettiness: An Inclusive Event Shape to Veto Jets, Phys. Rev. Lett. 105 (2010) 092002.
28. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, The Quark Beam Function at NNLL, JHEP 1009 (2010) 005.
29. I. W. Stewart, F. J. Tackmann, and W. J. Waalewijn, Factorization at the LHC: From PDFs to Initial State Jets, Phys. Rev. D81 (2010) 094035.
30. W. J. Waalewijn, The Chiral Anomaly in SCET, Phys. Rev. D79 (2009) 036003.

Papers:

• arXiv

• Inspire

Public results:

• ATLAS
• CMS

Local talks:

• Nikhef Theory Seminar (Thursdays)
• Grappa (journal club and seminar on Mondays)
• UvA Colloquium (Thursdays, once a month)

Recent workshops I attended:

• MPI@LHC 2014
• GGI: Prospects and Precision at the LHC at 14 TeV
• Astroparticle Physics 2014
• SCET 2014
• Boston Jets Workshop 2014
• BOOST 2013 

Some lecture notes:

• Iain Stewart: Effective Field Theory
• Christoph Paus: LHC experimental methods and measurements

Booking travel:

• Kayak
• Hotels

No known ancillary activities