New Homepage Jos
Engelen 
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
Dutch corner
Maart 2025
Ingezonden brief met Walter Hoogland over Europa, helaas (weer) geweigerd door NRC
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:
Update in time-reversed order (November 2024): the company LazeraH advertizes on its webpage www.lazerah.com that ultradense hydrogen for energy production has been rated among the 100 most promising projects by the Royal Swedish Academy of Engineering Sciences (IVA). THIS IS SIMPLY NOT TRUE, I checked with IVA. This is misleading if not fraudulent.
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 19, 2025, Nikef Annual Meeting, Nijmegen
Award of the Kluyver Prize 2024
September 11, 2024
Symposium Fosterfest, Oxford (retirement and 70th anniversary prof. Brian Foster)
My talk (Zoom) here and .ppt sheets here
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).
STRATEGY for the future of Particle Physics:
December 2023(and later additions)
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
An article in Nature, only partly
Open Access unfortunately here , Nature 639, 560-563 (2025), doi: doi: https://doi.org/10.1038/d41586-025-00793-x
Another article in Nature on CERN's future here.
March 2025, contribution Early Career Scientists.
March 29, 2025 article in the Guardian
Another point of view: Linear Collider Facility (LCF) at CERN.
March 31, 2025. Future Circular Collider Feasibility Study Report announcement and links to 3 volumes here
Article by secretary strategy process Karl Jakobs in CERN Courier (March 24, 2025) here .
Article by director for accelerators and technology, Mike Lamont, in CERN Courier (March 26, 2025) here .
The 263 (!) submissions for the European Strategy of Particle Physics are now online, here is the link. Personal observation: the strategy process gets out of hand... What we need is a vision on the process itself and on the substance matter and a way forward, not a diaspora. Added observation: the (263) documents referred to above make very interesting reading.
The list of 263 contributions is very 'untidy', not easy to survey, it is an incoherent sum of inputs. Here is the link to the contribution from the Netherlands: NL contribution .
An informative thread by P. Koppenburg on X here.
Link to Indico page colloquium on ESPP by Tristan du Pree here and direct link to file with the talk here .
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). https://doi.org/10.1186/s13705-023-00403-6
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. Note added: Paul 't Hart won an NWO Stevin award in 2024.
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
