A colleague shared on twitter this CERN video claiming that “1€ invested in CERN’s research brings 1.8€ back”.

I expressed doubts, and later I noticed that CERN blocked me. I don’t know why/when it happened, as I was not following it.

Anyhow, I know my scientific field, so let me freely speak about this issue.

Let’s start from doubts about the specific claim by CERN. The source of the claim appears to be the CERN-ACC/2018-0014 document with title “Social Cost Benefit Analysis of HL-LHC”, available at https://cds.cern.ch/record/002319300.

Its authors claim that, according to their computer simulations, 1€ invested in the CERN HL-LHC project could bring back 1.15€. The uncertainty should be at least ±0.10€, given that the authors write that the economic return is negative in 6% of their computer simulations. But what are their computer simulations based on? Table 1 of CERN-ACC/18-14 values the full HL-LHC program as follows: 

Total costs: 22.3 billions of CHF “net to the share due to scientific personnel costs”.

Total benefits: 25.6 billions of CHF, estimated as

• 2% i.e. 0.6 billions from the “scientific publications” (yes, CERN-ACC/18-14 indirectly says that the direct value of high-energy physics is almost a 100% loss!).
• 12% i.e 3.1 billions from the “public good value” (it means people feeling happy about possible scientific progress).
• 13% i.e. 3.3 billions from the “cultural benefits” (the listed concrete examples include CERN visitors, media articles and movies… and the CERN twitter account that blocked me: I lost billions?).
• 33% i.e 8.4 billions from the “human capital” (the listed examples include students who spend time at CERN and later find a better job; firms that get money by interacting with CERN and selling high technology…).
• 40% i.e 10.2 billions from the “technological spillovers”. This sounds more concrete, but it’s defined in a broad sense as “this category does not require the creation of new intellectual properties, new technical principles or designs. The mere gain of experience working in a large-scale international project…”. As a concrete example, CERN-ACC/18-14 mentions the software GEANT, that simulates particle interactions with matter. My physics understanding is that the indirect applications of this code in medicine and material science need particle interactions at energies explored half a century ago, not at the high energies explored now.

I see two problems: first these billions are not real quantifiable money. Second, if what has most value is training students and motivating industry, this can be done without spending billions on high-energy physics. Students can attend universities, and throwing money at smart researchers can generically be a good investment. High-energy physics used to attract smart researchers, but this science now needs giant experiments and huge collaborations, two factors that limit innovation. Indeed, a multi-billion project managed by thousands of persons seems to me not the optimal environment where individuals can risk innovations. And future main projects involve excavating a 100 km tunnel: finding spillovers for this will be a challenge.

Finally, the science. Its value is estimated as 2% in CERN-ACC/18-14, so we could just neglect it. But it’s my field, so I am interested in it. The CERN-ACC/18-14 paper assigns a monetary value to publications and citations until 2063. My 210 publications received 43167 citations, that should correspond to millions of €: I wish these were real.

Fig. 6 of the CERN-ACC/18-14 paper, reproduced below, implies a striking claim: high energy LHC physics peaked in 2014, and is now declining, but will be saved in 2030 by a “high luminosity” upgrade.

So, CERN-ACC/18-14 does not claim nor proof that “1€ invested in CERN’s research brings 1.8€ back”.

Its authors only estimate that the specific future “high-luminosity” upgrade of LHC could bring 1.74€ back for each additional € invested. However, this is estimated as the difference between a “smaller” 19.3 billion LHC project and a 22.3 billion upgrade, so it’s highly uncertain and based on optimistic opinions about the “high luminosity” upgrade. My opinion is what I told privately to the colleague who said me: “I just got out of the meeting, the high-luminosity project is approved”. I find it depressing, my scientific interest in CERN declines. This happened around 2018.

We can now check what happened next looking at real bibliometric data. A quick significant way is counting how many scientific papers CERN-TH produced each year (link to data). The plot below shows a growth until 2000, next a decline when the previous LEP collider ended, next some increase in 2010 when LHC started, next the decline I expected. (The current 2022 post-covid year shows a new low, but a few extra 2022 papers could appear in 2023). The positive impact of LHC was mild because it discovered no new physics beyond the Standard Model. This is the problem, so just repeating LHC again with “high luminosity” will not be enough to bring back in 2030 the interest that was justified in 2010.

This is why I don’t expect that a new Golden Age in 2030 will give a 1.8€ return for each € invested.

To conclude, my historical perspective.

A century ago physicists understood what matter is. During this golden period, progress in fundamental physics had huge practical relevance: new discoveries made people and countries really richer, and could be used for new experiments that gave new discoveries. This virtuous cycle attracted the smartest people and allowed to recognise the beautiful deep principles of fundamental physics. After 1945 nuclear physics got huge funds that allowed to explore energies higher than those of ordinary matter. These experiments discovered new forms of matter, but at energies so high that the new particles decay so fast that they found little practical applications, not even for building better colliders. So new colliders kept using normal matter only. New colliders become bigger and bigger as dictated by basic laws of physics, and got funded thanks to past prestige. But prestige fades away while costs grew and now hit human resources and time-scales. 

The LHC “only” discovered the boson predicted by Higgs 50 years ago. Nobody found a practical application of the Higgs boson. So its economic value is zero. When debating funds in the US, Wilson honestly said that this science “has nothing to do directly with defending our country except to make it worth defending”. 

This is the real argument, we should not undermine it.

Declarations of conflict of interest. 

I am one of the persons that would most benefit from future interesting higher-energy physics colliders, as I proposed theories and I would like to know what is real.