[tsimionescu]

> No one thinks new particles will be discovered.

Blatantly false. Plenty of FCC docs from CERN itself mention the possibility that new particles could be discovered, from dark matter to axions. They even think they could help gather data to guide searches for supersymmetric partners.

[edited to add links and quotes]

https://fcc-cdr.web.cern.ch/reports/EPPSU18_FCCint.pdf

> In addition to the dark matter examples given before, Volume 1 documents the extraordinary sensitivity to less-than-weakly coupled particles, ranging from heavy sterile neutrinos (see Fig. 5, right) down to the see-saw limit in a part of parameter space favourable for generating the baryon asymmetry of the Universe, to axions and dark photons.

https://fcc.web.cern.ch/physics

> Future searches at lepton and proton colliders would further constrain any viable scenarios and put progressively tighter bounds to SUSY candidate particles. Searches could profit from data collected at the FCCs as they will allow better discrimination of the Standard Model backgrounds but also deliver more information for event reconstruction.

[pclmulqdq]

Supersymmetry is on its last legs after the LHC didn't find any supersymmetric particles. WIMPs and other dark matter particles are now no longer speculated to be on the menu because they are too light for this energy range.

There's lots of "could" in your own post and your sources. Very little "will" - as in "will test X theory."

[tsimionescu]

The poster above was claiming, in several posts, that the people at CERN and experimental particle physicists more broadly are being unfairly represented by claims that they are including possible new particles in the case for building the FCC. They even found an IEEE publication about it that (apparently) made no such claims and stuck to well motivated physics.

I was merely showing that there is nothing unfair about it, as all materials about the FCC, at least from CERN, come with beliefs about the chance that new particles could be found. Sure, they don't make hard claims that they will be found. But even these claims that they could be found are unfounded. It's just as likely that I'll spot a WIMP in my oven if I look carefully while it's pretty hot as WIMPs being found at the FCC. This speculation has no place in serious discussions about this level of spending and human effort.

If this were an abstract discussion at a panel and someone was asking "what are some speculations about what we could see at the FCC", it would be perfectly fine to go on about SUSY and dark matter detection and axions and whatever else. But this has no place whatsoever in official documents about the scientific purpose of allocating billions of euros to this project. It is blatant speculation to pad out an otherwise pretty thin motivation. It's like writing a proposal for a new build system at your company and including speculation that it might detect security vulnerabilities automatically, or it might reduce build times a hundred fold.