Jos J. Engelen

Faculty Professor-em., Faculty of Science, University of Amsterdam and NIKHEF

Address: Nikhef, Science Park 105, 1098 XG Amsterdam
Tel. +31(0)20 592 2142 | engelen at


A brief CV you find here and a list of scientific publications. Most of these publications can be found at and here with a targeted search (with a few entries of persons with the same name). Top citations (for what it is worth..!)   here Here a list of former Ph.D. students and their current whereabouts, send me updates :)

One publication I am particularly fond of: MEASUREMENT OF DEEP INELASTIC COMPTON SCATTERING OF HIGH ENERGY PHOTONS, CERN/EP/85-07, 18 January 1985. Available here.

Current activities include: member Supervisory Board Waddenacademie
Member RvC Matrix Innovation Center
Former 'Third' member of the Executive Board of NeCEN The Netherlands Centre for Electron Nanoscopy
Until recently: Associate editor for European Physical Journal EPJ C

Peter Higgs at CERN attending the presentations on the discovery of the Higgs boson, 2012; at his left me, by pure coincidence, and partly visible Roger Cashmore. At his right a colleague from Edinburgh, I think.
Buttons to the various chapters of this site:

Dutch corner

Mei 2024
Nieuwe editie Nikhef magazine DIMENSIES, met aandacht voor 70e verjaardag van CERN op pag. 18 e.v.

April 2024
Bijeenkomst met enkele jaargenoten scheikunde (Nijmegen 1967) over elemenraire deeltjes en zo. Zal proberen een mooi rapportje te schrijven.The 'sheets' I used to support the discussion are HERE. Powerpoint ALSO Available

Hier een oplossing van de 'cycloïdeslinger' van Christiaan Huygens
en een prachtig arikel van Jan Aarts over Horologium Oscillatorium van Christaan Huygens.

An article an addendum and an erratum in Dutch on a 1927 photo taken in Leiden, with, among others, Dirac, Oppenheimer. Looking for information on Josephus Spier (1904-1944) living at Transvaalplein in Amsterdam, physicist, teacher, social democrat, journalist (Het Volk) - Louk Lapikás and I are working on an article to commemorate him.

A number of articles on historical topics (quarks; relativity; Zeeman effect; discovery electron; invention cloud chamber (in Dutch):

'Hoe quarks hun entree maakten in ons wereldbeeld via kosmische stralen en protonversnellers'
Deel 1 van het NTVN artikel verscheen in het januari 2024 nummer, reprint hier.
Deel 2 verscheen in het februari 2024 nummer, reprint hier.

'Van elektron tot higgsboson - Van vacuümbuis tot deeltjesbotser en van Wilsonvat tot pixeldetector'
The discovery of the electron by Thomson and more (Wilsonchamber). (in Dutch). Reprint deel 1 (mei 2022) hier en reprint deel 2 (juni 2022) hier

'De ontdekking en verklaring van het Zeemaneffect'
History of the Zeemaneffect (in Dutch) deel 1 en deel 2 in Nederlands Tijdschrift voor Natuurkunde november 2021, december 2021.

'Hoe de ether verdween uit de natuurkunde'
Historical perspective on the discovery of the Lorentz transformations (in Dutch) (published in Nederlands Tijdschrift voor Natuurkunde in november 2020, december 2020): deel 1 (tot 1892) en deel 2 (t/m 1905)

Temporary topical special subject:

I started to question the validity of claims on the production of ultra-dense hydrogen in January 2022, soon joined by Klavs Hansen who had voiced criticism earlier. Meanwhile (January 2024) our criticism appears to be taken seriously, so this chapter will be closed soon.
However: as recent as 2023 the journal Astrobiology published a paper on ultra-dense hydrogen and its supposed baring on the atmosphere of Venus. We wrote a comment that was rejected by this journal, not because it was wrong, but because the article we criticized might be correct:) Well, it is NOT! Here is the COMMENT.

In Dutch:dit commentaar geïnspireerd door een artikel van Maxim Februari.

On ultra-dense hydrogen as a medium for 'spontaneous' appearance of antiprotons and their subsequent annihilation. To be clear: my indignation does not apply to the person(s) who wrote these articles but to those who published them in the peer reviewed scientific literature. They should retract this NONSENSE. They have no mechanism for this, they say...

Go to this page

May 13, 2024
Award of Kluyver Prize 2023, report of the jury

January 2024
Wrote an article 'How quarks made their entrance into our worldview'. Original version in Dutch, submitted to Ned. Tijdschrift v. Natuurkunde. The English version can be found on arXiv here. A related article by Chris Llewellyn Smith in EPJH here. Another by Vladimir Petrov here. These two authors emphasize the contributions of A. Petermann to the creation of the quark model, overlooked by many authors (including myself).

December 2023
In view of recent strategy discussions in the US, also have a look at: Charting the European Course to the High-Energy Frontier and at the website of the Strategy Group: EUROPEAN STRATEGY FOR PARTICLE PHYSICS.

Here is the US report (P5).

Here is a recent presentation on
Chinese plans for a future collider (in two steps like CERN's FCC). A draft version of the Technical Design Report is available.

Note added Joint statement USA and CERN

By the way: at the time of LHC turn-on there were public discussions about the danger of 'disturbing the universe' through man made black holes and new forms of matter such as 'strangelets'. We should settle these issues for a future 100 TeV collider now, not at the very last moment. See: these references. and this link to

November 2023
"Comment on ‘Ultradense protium p(0) and deuterium D(0)and their relation to ordinary Rydberg matter: a review’ (2019 Physica Scripta 94 075005 )" has been published in Physics Scripta: here. Citation: Klavs Hansen and Jos Engelen 2023 Phys. Scr. 98 127001 DOI 10.1088/1402-4896/ad05c7

October 2023
As a follow up to a tweet on X, here is a note on Einstein's original (1905) derivation of the Lorentz transformations, which was confusing, or inconsistent, or sloppy, or wrong... Click here.

July 2023
A published comment by Klavs Hansen and Jos Engelen on a claim of cheap muon production for building a fusion reactor based on muon catalyzed fusion: here. Cite as: Hansen, K., Engelen, J. Are claims of cheap muon production correct?. Energ Sustain Soc 13, 24 (2023).

May 2023
Speech at the occasion of the award ceremony of the 2022 Kluyver Prize. See also dedicated webpage. Award ceremony 2023 Kluyver Prize May 13, 2024, Nikhef Annual Meeting, Amsterdam.

October 14 2022
Seminar in honor of Jim Virdee : Programme .
My talk (with slides appended) here

A while ago
I co-authored (with Paul 't Hart) a chapter (chapter 9) in the book Guardians of Public Value. The book is Open Access, chapter 9 is entitled: CERN: Guardian of the Human Aspiration to Understand the Universe

Minisymposium and valedictory lecture ('afscheidscollege') on March 10, 2017, Aula UvA. The lecture: text. The slides (without animation, however) are here
The write-up of the lecture can be found here

Orange = Dutch:
Afscheid Algemeen Bestuur NWO, 7 december 2016, Glazen Zaal, Den Haag, korte speech

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