
CERN's Future Circular Collider (FCC) Conceptual Design Report [pdf] - movaxdx
https://www.researchgate.net/publication/334148892_FCC-hh_The_Hadron_Collider
======
greggman2
would love to read comments on Sabine Hossenfelder book "Lost in Math" related
to this

[https://www.goodreads.com/book/show/36341728-lost-in-
math](https://www.goodreads.com/book/show/36341728-lost-in-math)

She basically makes the claim we have no good scientific reason to build this
at the moment

~~~
TheWizardofOdds
A Problem with accelerator physics particularly is that there is a large
scientific industry around the actual experiments that depend on these
experiments continuing. The engineers just get told what to build and they get
going, without having a deep understanding why this particular experiment is
really necessary. I worked in accelerator physics for 5 years and on all the
conferences, meetings etc. I had yet to meet anyone who understands, why we
are doing this (with an understanding that goes deeper than Wikipedia).

~~~
sdwa
Well, accelerator physicists work with particle physicists who do understand
these things. More often than not particle physicists don't understand how the
accelerator works. Particle physics is complicated, and so is the LHC. I am
not sure it's right to expect people to be experts on both, it's surely better
for people to specialise.

Regarding Hossenfelder: I think she is an iconoclast and arch contrarian.

~~~
eth0up
"arch contrarian"

Could make a good title for one of her German synthpop music videos, which I
kindof dig.

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willis936
The omega tau podcast had an interesting episode on this.

[https://omegataupodcast.net/231-the-future-circular-
collider...](https://omegataupodcast.net/231-the-future-circular-colliders/)

There is also an interesting episode on mega projects in general.

[https://omegataupodcast.net/181-why-megaprojects-fail-and-
wh...](https://omegataupodcast.net/181-why-megaprojects-fail-and-what-to-do-
about-it/)

~~~
jgalt212
yes, the few omega tau podcasts I have listened to, have been excellent. Alas,
many of them are not in English.

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CRUDite
Well, why not? As many point out it has interesting engineering challenges,
and gives particle physicists something to do.. However, maybe there is
nothing to do after all. One wonders if this is a last hail mary for those
clinging to super symmetric particle theories or maybe for multiple higgs
ideas. Or just for a job. There doesnt seem any sound reason to me to think
the particle desert isnt real and wont stretch all the way to GUT energy.
Though i suppose 13.4 - 100 may yield extra discoveries of some nature. I used
to read this blog
[http://resonaances.blogspot.com](http://resonaances.blogspot.com), though im
not a particle physicist, it was interesting. The posts dried up and it was
hard not to detect pessimism after a null result via supersymmetry. Indeed i
seem to remember hearing no one would want to go into particles as a career
now and many will pivot into condensed matter physics etc. So what are they
gonna do for 25 years? I guess the youngsters 25 years hence will have to dust
off the particle books. Meta materials, gravity waves and plasma physics are
so much more intetesting now.. I seem to remember reading about plasma wave
accelerators the size of a table top many years ago with giant theoretical
energies. Interesting to note the ssc had 40 Tev energy which would have
fairly concretely answered the ss question without the need of another machine

~~~
nxpnsv
Contrary to popular belief, there’s lots of work going on in experimental
particle physics, and there’s a lot planned. Physics didn’t stopp in 2012 with
Higgs discovery, it is not likely to stop in the near future either.

~~~
scottlocklin
High energy experimental physics died in the 1973. It's long since been time
to pull the plug on this zombie. It was obviously true in the 90s when I was
picking a specialization. It's even more true today.

~~~
nxpnsv
I’ve spent 18 years in the field. But what would I know...

~~~
scottlocklin
Compare the last 18 years with, say, the period from 1955 to 1973. There are
still people who write poems in Latin as well. They don't cost much, nor do
they channel large populations of intelligent people away from real problems.

~~~
nxpnsv
You imply there were no benefits from lhc? It’s not incredibly expensive per
scientist (there are single hospitals with larger budgets than a lhc
experiment), and it had a massive impact - for instance you know about it.
Basic research is important, if you don’t agree, try educating yourself - i
won’t do it for you.

~~~
scottlocklin
>You imply there were no benefits from lhc?

I have overtly stated as much, in as public a way as I had access to at the
time. I don't care if it's "not incredibly expensive per scientist" -it is a
wasted effort, and an awful lot of what gets published (with 1000 "authors")
as being bullshit. I've also seen the lifestyle and read the "results" of both
experimental high energy and the theorists: it's basically a cargo cult at
this point, imitating the glory days in the 50s and 60s.

Let me ask you a question: what lack of result would convince you that high
energy as practiced today is a waste of time? I look at stuff like this and
see sheer decadence:

[https://kirstenhacker.wordpress.com/2019/09/29/the-walrus-
an...](https://kirstenhacker.wordpress.com/2019/09/29/the-walrus-and-the-
carpenter/)

The "muh basic research" argument doesn't work forever. "Which basic research"
is a question we should be asking, and building yet another giant accelerator
and detector set up is not necessarily the answer, just because that's been
useful in the (now distant) past. Phil Anderson is probably right.

------
abrichr
Some interesting numbers:

\- From the abstract:

> _Combining ingredients from the Large Hadron Collider (LHC), the high-
> luminosity LHC upgrade and adding novel technologies and approaches, the
> FCC-hh design aims at significantly extending the energy frontier to 100
> TeV._

\- From the paper:

> _The overall project duration of FCC-hh as a “stand-alone” project is 23
> years, composed of two major parts: the preparation phase spanning 8 years
> and the construction phase spanning 15 years._

\- From Wikipedia [1]:

> _First collisions were achieved in 2010 at an energy of 3.5
> teraelectronvolts (TeV) per beam, about four times the previous world
> record. After upgrades it reached 6.5 TeV per beam (13 TeV total collision
> energy, the present world record)._

[1]
[https://en.wikipedia.org/wiki/Large_Hadron_Collider](https://en.wikipedia.org/wiki/Large_Hadron_Collider)

------
jessriedel
Annoying that this apparently isn't on the arXiv. Here's an alternative direct
link.

[https://www.repository.cam.ac.uk/bitstream/handle/1810/29453...](https://www.repository.cam.ac.uk/bitstream/handle/1810/294539/FCC-
hh.pdf)

------
TaylorAlexander
This is super fun! It’s huge but just skipping through to check out diagrams
and read bits and pieces is great.

------
kristianp
The LHC, has 13 TeV total collision energy, this intends to go to 100TeV in
about 20 years. Is that sufficient to find new science? Should they be aiming
for a much higher energy? Less than 10 times increase doesn't seem much, for a
multi billion dollar project.

~~~
willis936
It isn’t a simple matter of making a number bigger. The size and cost goes up
exponentially. There are potential new particles that can be teased out of 100
TeV. Some important particles aren’t expected to be seen in colliders smaller
than a thousand light years.

------
mellosouls
A dozen (!) pages listing the contributors, then an abstract which ends with
the paragraph quoted below which essentially says it's more powerful and wth
vague aims.

I hope the intended audience aren't political and financial decision makers
who are otherwise laymen on the subject.

Presumably this is aimed at fellow scientists? What's the goal of the
document? What is the specific Higgs-equivalent target of the proposed
collider? I didn't read further tbh, I wasn't encouraged by the first few
pages, but then I'm not a physicist so perhaps that isn't intended.

From the abstract:

 _the FCC-hh design aims at significantly extending the energy frontier to 100
TeV. Its unprecedented centre- of-mass collision energy will make the FCC-hh a
unique instrument to explore physics beyond the Standard Model, offering great
direct sensitivity to new physics and discoveries._

~~~
siscia
Sorry, but I am afraid you are ill informed on the ammount of complexity that
this document cover.

Please note that never ever in the history of mankind a project so ambitious
has even be thought. Already the amount of complexity in LHC is considered far
greater than the complexity of the Apollo mission. FCC is a different order of
magnitude than LHC already.

Then if you just skim the report you will notice how wide are the topic
covered.

Leaving aside the physics, the document talk about the magnets, how to detect
quenches, how to discharge magnets that hold 37MJ of energy, how to monitor
the beam of particle, how to dump the beam, how to inject the beam into FCC,
how to accelerate the beam,how to keep 100km of magnets at 1.9k when particles
at 100TeV are running inside and doing it not for a bit, but continuosly for
months and months.

And then other points more pragmatic, where to get the electric energy to run
the whole machine?

And this just skimming the document and looking at pictures.

Honestly, how many would you expect to write such a document?

~~~
mellosouls
I think you've completely missed my point and have not answered a single of my
questions.

In particular, I'd like you to not "leave aside the physics" \- my
understanding is that's quite important here - and specify what part of theory
this will confirm or reveal.

I may well be "ill-informed", I'm happy for you to clear that up with an
example along Higgs-discovery lines - the abstract and first dozen pages were
unable to.

You reference the Apollo mission as a relatively minor affair in comparison,
so that could serve as an example.

What is the "putting a human being on the moon" thing we are doing here? The
abstract as it stands is more like "we're gonna shoot some multi billion
dollar rockets into space and see what happens".

~~~
Someone
I wonder whether it is worth spending as much as this would cost, but I don’t
expect that to be answered in a “Conceptual _Design_ Report. Design time is
not where you justify _why_ you’re building what you’re building; you only
describe _how_ you’re planning to do it.

Presumably (I haven’t looked hard for them) there are earlier report(s) that
argue _why_ we would want to look at 100 TeV.

Edit: [https://fcc-cdr.web.cern.ch/](https://fcc-cdr.web.cern.ch/) has some
more high-level info, such as ‘FCC Physics Opportunities’ ([https://fcc-
cdr.web.cern.ch/#FCCPO](https://fcc-cdr.web.cern.ch/#FCCPO)), which refers the
“European Strategy for Particle Physics”
([https://europeanstrategyupdate.web.cern.ch/](https://europeanstrategyupdate.web.cern.ch/))
which, presumably answers the ‘why’

~~~
mellosouls
That's a fair answer thank you (and why I asked about the intended audience
and purpose of the document); however as they put the blue sky goals in the
abstract, I would have expected something more specific as well.

Wrt your first observation, yes it's particularly the amount that it costs
that I think makes this clarity in communication especially important.

