[HN Gopher] CERN releases report on the feasibility of a possibl...
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       CERN releases report on the feasibility of a possible Future
       Circular Collider
        
       Author : gmays
       Score  : 47 points
       Date   : 2025-04-09 14:52 UTC (3 days ago)
        
 (HTM) web link (home.cern)
 (TXT) w3m dump (home.cern)
        
       | teekert wrote:
       | Sabine is skeptical [0]. Is it really true that there a no
       | theories that are proven or dicarded with this experiment, and
       | that the Chinese have plans to do it much faster? Her video is
       | pretty damning.
       | 
       | [0] https://backreaction.blogspot.com/2025/04/why-cerns-new-
       | coll...
        
         | jameskilton wrote:
         | The utter lack of significant discoveries at the LHC after the
         | Higgs (2012!) is a pretty telling sign. Any bigger collider is
         | riding purely on the hope that something will make the effort
         | worth while.
        
           | refulgentis wrote:
           | There's been plenty of significant discoveries, many, many.
           | (O(10)s hadrons, consistent standard model discrepancies are
           | really big news, those weren't expected)
           | 
           | There hasn't been a significant new _particle discovery_ ,
           | but none was expected other than Higgs, as far back as 2006
           | when I was still screwing around in graduate physics.
           | 
           | I honestly can't remember the last time a new particle was
           | randomly discovered by experiment that wasn't already
           | proposed and agreed to as sound-in-theory. It's much cheaper
           | and faster to do theory, then built what you need to verify,
           | than to crank up energy as high as you can and hope for the
           | best (I'd hazard a guess this ran out of steam by the 50s/60s
           | at the latest)
        
           | pfdietz wrote:
           | I'm not a physicist, but if I understand correctly there's
           | likely new-ish physics to be found in Higgs-Higgs
           | interactions.
        
             | cyberax wrote:
             | There is a _hope_ that there's new physics there. But so
             | far, nothing indicates that the next collider will find
             | something.
             | 
             | There is definitely new physics to be discovered, but it
             | might need a collider the size of the Solar system for the
             | discovery.
        
         | refulgentis wrote:
         | Sabine is something other-than a good source on how physicists
         | actually think about things at this point, unfortunately.
         | 
         | It's not true at all.
         | 
         | I'll come back and write some up over the next 20 minutes.
        
           | gadflyinyoureye wrote:
           | I look forward to it. I listened to her a lot recently
           | because YouTube decided ever "next video" bump while I drove
           | should be her.
        
             | refulgentis wrote:
             | Blissfully, I found an IEEE article that collects the stuff
             | I'm aware of in one neat package.
             | https://spectrum.ieee.org/supercolliders
             | 
             | The shell games are:
             | 
             | 1. claiming it is a proton collider[^1 source] designed to
             | look for new particles [^2 comment].
             | 
             | 2. false equivalence between China putting in their latest
             | 5 year plan to make a plan to make something that will
             | transition to being a proton collider. And it's worse than
             | that:
             | 
             | If they immediately started after the plan was complete and
             | on schedule, they'd be done in 2048 and transition from e/p
             | to protons in 2066.
             | 
             | CERNs plan is to be done with e/p in 2042 and transition to
             | protons in 2070. That's 4 years later, but it's comically
             | irrelevant. That's not getting done sooner, that's just
             | transitioning to doing stuff we already can do faster, the
             | cool thing and why _both_ are interested in building one is
             | the _electron /positron_ collider stuff, not scaled up
             | proton collider stuff.
             | 
             | Content: - The project would transition to a _proton
             | collider_ at the end of its lifespan as a novel tool, in
             | 2070.
             | 
             | - It is proposed to operate by 2042, assuming funds
             | dispersed over 12 years, starting in 2030.
             | 
             | - It will operate as a _electron-positron collider_ for the
             | intervening ~3 decades before transitioning to essentially
             | LHC with 4x power.
             | 
             | - Electron / positron is a unique collision form, chosen to
             | allow for _more precise measurement_ , such as the LHC
             | discoveries of discrepancies in the Standard Model.
             | 
             | - This is very important work. The more precise you nail
             | down these uncertainties, the more theorists can do to
             | verify their work, allowing the experimentalists to know
             | where to look for new stuff, if any.
             | 
             | [^1 source] Via Sabine link: "CERN wants to build a new
             | particle collider which will smash protons together at
             | roughly 6 times the energies seen at the Large Hadron
             | Collider."
             | 
             | [^2 comment] This is the undercurrent of the whole
             | criticism, I cannot explicitly source it to one sentence.
             | It's also bizarre: I can't remember the last time
             | experimentalists got to discover something without the
             | theorists telling them where to look. It's cheaper that
             | way! LHC was a failure too by that standard. There simply
             | aren't any candidates in the theory that are accessible at
             | humanities near-term energy levels, the Standard Model's
             | worked beautifully, _modulo these tantalizing discoveries
             | at LHC of small discrepancies_ that electron /positron
             | collisions let you explore.
        
               | raziel2701 wrote:
               | Why is this work important? To me it just feels so
               | distant from my reality. At the core of this, is there an
               | answer to the "who cares?" attitude?
               | 
               | Because if the answer is that we might incidentally
               | create new useful technology in the build up of a new
               | collider, why not just diversify the investment and put
               | that money into a bunch of smaller projects? Hedge your
               | bets sort of thing.
               | 
               | Why support this and not allocate more into high
               | temperature superconductivity for example? I don't
               | understand what is the justification that entitles such a
               | large amount of money to a singular project.
        
           | Ygg2 wrote:
           | Sabine also have wasn't the only physicist that thinks FCC
           | would be dead on arrival.
        
             | elashri wrote:
             | I would be very interested in the list of physicists who
             | thinks FCC would be dead on arrival. Can you provide
             | source/s of this list?
        
           | dr_kretyn wrote:
           | Not sure who you are and why would your opinion matter here
           | but I'll take you on your comment. Looking forward to your
           | write up.
        
             | msm_ wrote:
             | It's already here by the time you wrote -
             | https://news.ycombinator.com/item?id=43668292.
        
         | elashri wrote:
         | > wouldn't be operational until the 2070s That's for the pp/hh
         | stage not when it will take data. Sabine is misleading here.
         | The plan is to start in 2042
         | 
         | This will depend on level of funding and when are we actually
         | going to start construction and have the investment. This is
         | huge project that will involve state of art technologies that
         | need a lot of R&D. Also The HL-LHC upgrade will push LHC to
         | 2040s. Having expectation that in 2040s to get the next inline
         | project is normal. LHC started before two decades from Tevatron
         | shutting down. Most of the people who contributed to this
         | feasibility study will not be working (or alive) when this
         | project start collecting data. This is not something new as she
         | is trying to imply.
        
       | elashri wrote:
       | Before discussions go into some generic direction about the
       | field. This is a huge feasibility study contain different aspects
       | done by hundreds of people. People who are mostly interested
       | about the physics case of FCC should read/skim at least through
       | the first volume [1], second chapter (Specificities of the FCC
       | physics case) the first four sections. This is about 35 pages
       | with somehow accessible language to people with some physics
       | knowledge.
       | 
       | Personally I'm interested in their proposal about how they are
       | going to approach software (Section 8). They plan to provide
       | experiment agnostic and unified framework that is actually
       | unified and user accessible. The field really need something like
       | that, it is usually the pain point of most junior graduate
       | student. The field suck at documentation and keep coherent
       | software and write code in a bad way most of the time. I think
       | they can have much better framework than Fermilab's art [2].
       | 
       | [1] https://cds.cern.ch/record/2928193
       | 
       | [2] https://art.fnal.gov/
        
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