Rikkert Frederix
Former member
PhD student in CP3 from December 2005 to September 2009
Current position: Post-doc in Zurich.
Oct. 2008 - Sep. 2009
Marie Curie Early Training Theory Fellow at CERN.
Dec. 2005 - Sep. 2009 (expected)
PhD Student at the Centre for Cosmology, Particle Physics Phenomenology at the UCLouvain. Supervisor: Fabio Maltoni.
Sep. 2004 - Nov. 2005
Master's research on "Wilson lines in pQCD" under supervision of Eric Laenen at the nikhef institute, Amsterdam.
Sep. 2000 - Nov. 2005
(Under)graduate student at Utrecht University.
Research Activities
My research interests are focused on the study of the phenomenology of the standard model (SM) and its extensions.

I have started my Ph.D. working on the MadGraph/MadEvent (MG/ME) event generator. I have implemented new interactions, in particular the effective couplings between (pseudo-)scalars and gluons/photons. This has allowed me to familiarize with the implementation of new helicity routines and vertex structures in the MG/ME framework. I have also developed a code, MadAnalysis, suitable to analyze event files (LHEF and LHCO), i.e., produce plots, set analysis cuts, etc.
ZZ resummation
I have used the expertise gained during my Master's research on perturbative QCD, and in particular in the resummation of soft radiation in production and decays of strongly interacting particles, to calculate of the NLL soft gluon effects in double Z boson production at the LHC with Massimiliano Grazzini. We have implemented the results in a Monte Carlo program and compared our results with a fixed NLO calculation and with the results from the MLO event generator.
Top quark phenomenolgy
Furthermore I am interested in the phenomenology of top quark production and decays. In my first year of my PhD research I have take part to a common theoretical/experimental effort in our Centre (CP3), and proposed an improved method to set model independent bounds on the third row of the CKM matrix. In my second year I have spend quite some time to study the phenomenology of ttbar production, both in the SM and in 'model-independent' extensions. In this work we proposed a the possibility for a mass measurement of the top quark mass from the ttbar invariant mass and also a three-step analysis to discover and measure the properties of new physics resonances.

At the moment I am working in collaboration with John Campbell, Francesco Tramontano and Fabio Maltoni to study the NLO corrections to the t-channel single top production (starting from the 2->3 Born amplitude (4 flavor)).
Together with Thomas Gehrmann and Nicolas Greiner I am working on automatizing the dipole subtraction formalism for NLO in QCD calculations within the MadGraph/MadEvent framework. This includes automatic generation of the subtraction terms for the reals as well as the virtuals, and doing being able to do the (then finite) phase space integration.
Past projects
Hide past projects.

I am involved in the following research direction:

MadDipole: Automatic Dipole subtraction

Automatizing the Catani-Seymour dipole subtraction formalism for NLO in QCD calculations within the MadGraph/MadEvent framework. Both for the subtraction terms for the real and the virtual contributions.

External collaborators: Thomas Gehrmann and Nicolas Greiner.

Top quark phenomenology

Top pair and single-top production is investigated, both for SM measurements and BSM searches.

External Collaborators:
J. Campbell (Glasgow, UK), F. Tramontano (Univ. Napoli, Italy),
+ E. Laenen (NIKHEF), S. Frixione (CERN), C. White (NIKHEF)
+ EXP group at CP3 (A. Giammanco, V. Lemaitre,...)

Publications in CP3
All my publications on Inspire


The complete NLO corrections to dijet hadroproduction
Frederix, Rikkert and Frixione, Stefano and Hirschi, Valentin and Pagani, Davide and Shao, Hua-Sheng and Zaro, Marco
[Abstract] [PDF] [Journal]
Refereed paper. 10th December.
Mass effects in Higgs plus jets production
R. Frederix, S. Frixione, E. Vryonidou and M. Wiesemann
to be submitted to JHEP
Refereed paper. 4th April.


The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
Alwall, J. and Frederix, R. and Frixione, S. and Hirschi, V. and Maltoni, F. and others
[Abstract] [PDF] [Journal] to be submitted
Refereed paper. 4th April.


Diphoton production in the ADD model to NLO+parton shower accuracy at the LHC
R. Frederix, Manoj K. Mandal, Prakash Mathews, V. Ranvidran, Satyajit Seth, P. Torrielli, M. Zaro
[Abstract] [PDF] [Journal] 10 pages
Refereed paper. 28th September.


Automation of next-to-leading order computations in QCD: the FKS subtraction
Rikkert Frederix, Stefano Frixione, Fabio Maltoni and Tim Stelzer
[Abstract] [PDF] [Journal] Published in JHEP10(2009)003.
Refereed paper. 14th August.
NLO predictions for t-channel production of single top and fourth generation quarks at hadron colliders
John M. Campbell, Rikkert Frederix, Fabio Maltoni, Francesco Tramontano
[Abstract] [PDF] [Journal] Published in JHEP10(2009)042.
Refereed paper. 22nd July.
t-channel single-top production at hadron colliders
John M. Campbell, Rikkert Frederix, Fabio Maltoni, Francesco Tramontano
[Abstract] [PDF] [Journal] 5 pages. Published in Phys. Rev. Lett. 102, 182003 (2009)
Refereed paper. 28th February.


New Developments in MadGraph/MadEvent
J. Alwall, P. Artoisenet, S. de Visscher, C. Duhr, R. Frederix, M. Herquet, O. Mattelaer
[Abstract] [PDF] [Journal] SUSY08 Proceedings (plenary talk by Johan Alwall)
Contribution to proceedings. 15th September.
MadDipole: Automation of the Dipole Subtraction Method in MadGraph/MadEvent
Rikkert Frederix, Thomas Gehrmann and Nicolas Greiner
[Abstract] [PDF] [Journal] Published in JHEP09(2008)122
Refereed paper. 7th August.
Recent developments in MadGraph/MadEvent v4
Rikkert Frederix
[Journal] [Full text] Presented at the Loops & Legs 2008 conference, Sondershausen, Germany, April 2008.
Contribution to proceedings. 1st July.
Constraining CKM elements with direct top measurements
Rikkert Frederix
[Full text] Presented at the International Workshop on Top Quark Physics (TOP2008), La Biodola, Isola d'Elba, Italy, May 2008.
Contribution to proceedings. 1st July.
Collider aspects of flavour physics at high Q
del Aguila, F. and others
[Abstract] [PDF] [Journal] Report of Working Group 1 of the CERN Workshop Flavor in the Era of the LHC. Published in Eur.Phys.J.C57:183-308,2008.
Refereed paper. 14th January.
Higher-order QCD effects in the Higgs to ZZ search channel at the LHC
Rikkert Frederix and Massimiliano Grazzini
[Abstract] [PDF] [Journal] Published in Phys. Lett. B662: 353-359, (2008)
Refereed paper. 14th January.


Top pair invariant mass distribution: a window on new physics
Rikkert Frederix and Fabio Maltoni
[Abstract] [PDF] [Journal] Published in JHEP01(2009)047.
Refereed paper. 25th October.
MadGraph/MadEvent v4: from models to events
Rikkert Frederix
[Full text] ACAT07 workshop proceedings.
Contribution to proceedings. 26th July.
Madgraph/MadEvent v4: The new web generation
Johan Alwall, Pavel Demin, Simon de Visscher, Rikkert Frederix, Michel Herquet, Fabio Maltoni, Tilman Plehn, David Rainwater, Tim Stelzer
[Abstract] [PDF] [Journal] Published in JHEP 0709:028,2007
Refereed paper. 4th June.


Is Vtb=1?
J. Alwall, R. Frederix, J.-M.Gerard, A. Giammanco, M. Herquet, S. Kalinin, E. Kou, V. Lemaitre, F. Maltoni
[Abstract] [PDF] [Journal] Published in Eur.Phys.J.C.49 (2007) 791
Refereed paper. 29th June.

[UCLouvain] - [SST] [IRMP] - [SC]
Contact : Jérôme de Favereau
Job opportunities EOS be.h : 10 PhD positions
Postdoctoral position: Data Analysis and GTK operation for NA62 experiment
Postodoctoral position in precision and BSM Phenomenology
Postdoctoral Position in Precision Computations for the LHC