Gregory Soyez's home page
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Research in a nutshell
Generally speaking, I work on collider phenomenology and the study of strong interactions from first principles. My current research activities focus mainly on jet physics and on the development of new parton showers. I am also working on the physics of jets in the quark-gluon plasma. Over the past ~15 years, I have made several key contributions to the field like the anti-kt jet algorithm, FastJet (a package for jet finding), strategies for pileup mitigation, Soft Drop and the jet Lund Plane.
Other topics I work (or have worked) on include the physics of jets in the quark-gluon plasma and the study the high-energy limit of QCD with the group at the IPhT in CEA Saclay, an activity that I started when I was a PostDoc at the IPhT and pursued at the Brookhaven National Laboratory.
My earlier research experience, during my PhD, focused on the proton structure functions and the interplay between perturbative QCD and Regge theory. I have also worked independently on the structure of the QCD vacuum, using light-cone quantisation.
Employment
| 10/2018 - now: | CNRS Senior Scientist at the IPhT (CEA Saclay) |
| 09/2022 - 08/2023: | CERN Associate Scientist |
| 02/2010 - 09/2018: | CNRS Associate Scientist at the IPhT (CEA Saclay) |
| 10/2009 - 09/2010: | CERN fellow |
| 10/2007 - 09/2009: | Research Associate at the Brookhaven National Laboratory |
| 10/2004 - 09/2007: | Postdoc as a FNRS Research Fellow (Charg\'e de recherches) With this fellowship, I have visited the following places:
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Education
- 2017-03:
Habilitation thesis from the University Pierre et Marie Curie
Title: Pileup mitigation at the LHC, a theorist view} [PDF] - 2001-04:
Ph.D. in Physics from the University of Liege. Highest honours on January 6, 2004
Title: Deep Inelastic Scattering at small x: Perturbative QCD and S-matrix theory [PDF] - 2001-02:
D.E.A. (5th year degree) in Physics from the University of Liege. Highest honours
Title: The DGLAP equation: analytical properties and numerical resolution [PDF] - 1999-00:
License (4th year degree) in Physics from the University of Liege. Highest honours
Title: Light-cone quantisation, application to vacuum and zero modes - 1997-98: Candidature (2nd year degree) in Physics from the University of Liege. Highest honours
- 1997-98: Candidature (2nd year degree) in Mathematics from the University of Liege. Highest honours
Selected most-representative publications (both major achievements and recent interests)
The 3 works that lay basis for the current jet-reconstruction framework at the LHC:
- M. Cacciari, G.P. Salam and G. Soyez, The anti-kt jet clustering algorithm, JHEP 0804 (2008) 063 [arXiv:0802.1189], 9672 citations (as of Oct 10 2023).
- M. Cacciari, G.P. Salam and G. Soyez, FastJet User Manual, Eur. Phys. J. C 72 (2012) 1896 [arXiv:1111.6097], 5534 citations.
- M. Cacciari, G.P. Salam and G. Soyez, The Catchment Area of Jets, JHEP 0804 (2008) 005 [arXiv:0802.1188], 1202 citations.
Work on jet substructure with perturbative-QCD analytic control:
- A. J. Larkoski, S. Marzani, G. Soyez and J. Thaler, Soft Drop, JHEP 1405 (2014) 146 [arXiv:1402.2657], 920 citations.
- F. Dreyer, G.P. Salam and G. Soyez, The Lund Jet Plane, JHEP 12 (2018) 132, [arXiv:1807.04758], 144 citations.
Recent work on parton shower with improved logarithmic accuracy:
- S. Ferrario-Ravasio, K. Hamilton, A. KArlberg, G.P. Salam and G. Soyez, A parton shower with higher-logarithmic accuracy for soft emissions arXiv:2307.11142 (accepted for publication in Phys.Rev.Lett.), 5 citations.
- M. Dasgupta, F. Dreyer, K. Hamilton, P. Monni, G.P. Salam and G. Soyez, Parton showers beyond leading logarithmic accuracy, Phys.Rev.Lett. 125 (2020) 5, 052002, [arXiv:2002.11114], 113 citations.
Work on jet quenching (combining vacuum and medium-induced radiation):
- P. Caucal, E. Iancu and G. Soyez, Vacuum-like jet fragmentation in a dense QCD medium, Phys.Rev.Lett. 120 (2018) 232001 [arXiv:1801.09703], 92 citations.
Example work on pileup mitigation:
- M. Cacciari, G.P. Salam and G. Soyez, SoftKiller, a particle-level pileup removal method, Eur.Phys.J. C75 (2015) 2, 59 [arXiv:1407.0408], 124 citations.
Example of recent work done on the high-energy limit of QCD:
- E. Iancu, J.D. Madrigal, A.H. Mueller, G. Soyez, D.N. Triantafyllopoulos, Collinearly-improved BK evolution meets the HERA data Phys.Lett.B 750 (2015) 643-652 [arXiv:1507.03651], 131 citations.
Distinctions and grants
| 09/2018-08/2024: | Senior scientist on the Panscales Advanced ERC project (PI: Gavin Salam) |
| 12/2016: | Thibaud Prize of the ``Académie des Sciences, Belles Lettres et Arts'' in Lyon (awarded every 2 years in nuclear and particle physics) |
| 10/2016-03/2020: | member of the ANR DenseQCDAtLHC (Projet Blanc; PI: E.Iancu) |
| 10/2015-09/2019: | PI of the ANR OptimalJets (Défi de tous les savoirs) |
| 10/2011-03/2016: | member of the ANR CGC@LHC (Projet Blanc; PI: F.Gélis) |
| 10/2010-09/2014: | PI of the ANR Jets4LHC (Chaire d'Excellence) |
| 07/1997: | Roset Prize of the AMULg (Association of the Ulg Mathematicians), granted each year to a student in Mathematics |
| 07/1996: | Participation, with the Belgian team, to the 37th International Mathematical Olympiad. Bronze medal |
Supervision of students and postdocs
| 2020-2022: | Supervision of Alba Soto Ontoso' postdoc (PanScales ERC grant) |
| 2018-2019: | Supervision of Vincent Theeuwes' postdoc (German DAAD-Prime) |
| 2017-2020: | PhD advisor of Giovanni Stagnitto (with M. Cacciari, graduated in Sept. 2020) |
| 2017-2020: | PhD advisor of Paul Caucal (with E. Iancu, graduated in Sept. 2020) |
| 2017-2019: | Supervision of Davide Napoletano's postdoc (ANR OptimalJets) |
| 2017: | Master (2nd year) internship of Paul Caucal (with E. Iancu) |
| 2017: | Master (1st year) internship of Linnéa Gräns Samuelsson (with E. Iancu) |
| 2014-2017: | PhD advisor of Lais Sarem Schunk (graduated in Sept. 2017) |
| 2014: | Master internship advisor of Lais Sarem Schunk |
| 2011-2013: | Supervision of Ji-Hun Kim's postdoc (ANR Jets4LHC) |
| 2011: | Master internship advisor of Stéphane Dartois (ENS Lyon) |
Teaching experience
| 08/2023: | Lectures on QCD and Monte-Carlo generators at the CERN-Fermilab Hadron-Collider Physics School (CERN, 4 hours) |
| 02/2020: | Exploring High-Energy Physics with Jets, IPhT lectures (France, 10 hours) |
| 01/2019: | Lectures on QCD and collider physics at the GGI School on Fundamental Interactions (Firenze, 8 hours) |
| 06/2018: | Lectures on jet physics for the French GDRQCD school (France, 6 hours) |
| 04/2017: | External examiner for Heather McAslan (PhD) |
| 2011-2019: | Exercises for the QCD lectures at the ENS (Master 2) (6 hours) |
| 06/2016: | Lectures on jet physics at the QCDMasterClass summer school (France, 6 hours) |
| 06/2016: | Member of Matthias Saimpert's PhD jury |
| 12/2015: | Lectures on Advanced QCD at the UCL (Louvain, Belgium, 10 hours) |
| 10/2015: | Lectures on jets physics the Prague University (6 hours) |
| 2015: | QCD lectures at the ENS (Master 2) (12 hours) |
| 10/2014: | Member of Martin Zeeman's PhD jury |
| 09/2014: | Lectures on jets physics at a Summer school in Natal (Brazil, 6 hours) |
| 04/2014: | Lectures on QCD and jet physics at a school in Trento (Italy, 6 hours) |
| 09/2011: | Discussion Leader at the CERN European School of High-Energy Physics (Romania, 2011, 11 hours) |
| 09/2010: | Lectures on Phenomenology of hardonic collisions at the BND Summer School (Oostende, Belgium, 6 hours) |
| 12/2008: | Lectures on Advanced QCD at the UCL (Louvain, Belgium, 10 hours) |
| 2004: | Physics laboratories for 1st year students in Computer Sciences (50 hours/year) |
| 2003: | Physics laboratories for 1st year students in Computer Sciences (50 hours/year) |
| 2000-2001: | Programming exercises for B.A. students in Chemistry (30 hours/year) |
Institutional responsibilities
| 2018-2022: | Member of the IPhT Scientific Council (``Conseil Scientifique'') |
| 2016-now: | Member of the IT Committee (``Commission Informatique'') of the IPhT |
| 2016-2019: | Coordinator of the jet working group of the GDR-QCD |
| 09/2012-09/2016: | Member of the Section 02 (``Particle physics: Theory and Models'') of the French National Committee for Scientific Research (CoNRS) |
| 2011, 2013: | Jet contact for the Les-Houches Physics at TeV collider workshops |
Organisation of meetings and seminars
| 2023: | Co-chair (with Alba Soto and David d'Enterria) of the 1st Lund jet plane institute |
| 2018: | Main organiser (with Matteo Cacciari and Reina Camacho) of the Boost 2018 conference |
| 2016: | Main organiser (with Matteo Cacciari) of the PSR 2016 workshop |
| 2015: | Organisation committee for the conference ``Poetic 6'' |
| 2015: | Organisation committee for the conference ``Blois 2015'' |
| 04/2014: | Co-organisation of the workshop ``QCD and forward physics at the LHC'' |
| 07/2013: | Co-organisation of the ``Workshop on jets in Heavy-Ion collisions'', in Paris |
| 10/2011-now: | Co-organisation of the Particle Physics and Cosmology seminars at the IPhT (CEA Saclay) |
| 10/2008-09/2009: | Organisation of the Nuclear Theory Group seminars at Brookhaven National Laboratory |
© 2017-
Gregory Soyez
Last modification: January 10 2018