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CERN bids farewell to the LHC and enters Long Shutdown 3

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Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#71
post #26

Earlier quoted context omitted.

They're collecting 10X more data, at roughly the same energy per collision.

The article says "10x luminosity", and here's what seems to be the explanation. https://en.wikipedia.org/wiki/High_Luminosity_Large_Hadron_C... That's the wiki article for the new one. Says "Increasing LHC luminosity involves reduction of the beam size at the collision point, and either the reduction of bunch length and spacing, or significant increase in bunch length and population." The linked article says the new…

luminocity is collisions per second

energy is per individual collision

can't increase energy that much without increasing radius

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#72

Am I the only one that feels three/four years is a mighty ambitious timeline for the upgrade? It seems to be a very significant undertaking…

Keep in mind this is for the hardware work. We have been working on the HL-LHC from the physics / beam dynamics / everything else side for close to a decade now.

The other machines in the complex, which we call "injectors" from our mighty tower, have already undergone their own upgrade to be ready for HL-LHC, the LIU (https://home.cern/accelerator-chain-prepares-high-luminosity...).

Nonetheless there are plenty of things to be done and a lot of technologically engaging challenges ahead so this 3-4 years is still ambitious ;)

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#73
For anyone interested in doing some very special visits this will be a good timing. Long Shutdowns are the only moments where a lot of usually inaccessible places can be visited.

There should be (not yet officially confirmed) an open days after summer next year, just like there was in 2019. Short time frame but for a few days everything(-ish) is accessible, including going down in the LHC tunnel, but many more crazy places.

In the meantime there are still permanent exhibitions and guided tours for those interested. Come have a look at the cool science (made with your taxes)!

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#74
post #55

Earlier quoted context omitted.

I'm a former LHCb physicist and I worked for years in the cavern, fixing the cables you saw :) Thanks for your enthusiasm. Obviously, things seen from the inside aren't as ideal as a non-physicist person might think. There are the usual power dynamics you find in academia: PhD students and postdocs exploited to do service and technical work instead of independent research, careerism, researchers who have to worry mor…

> felt a strong sense of frustration at how modern research in particle physics is producing papers that are all identical to each other and have no true scientific impact Your comment above makes me think of Sabine Hossenfelder[1]. I'm sure you must've heard of her. I know she's somewhat of a "polarizing" figure. As a former "insider", do you think her core point stands? (Which is, the particle physics field has lar…

Yes, I know her and I agree with what she says. I also think many physicists working in the field secretly agree with her but it's a taboo to admit it openly. As an insider I can assure you that currently most analyses in experimental particle physics are a mechanical repetition of previous analyses with a few slight modifications to adapt them to the bigger statistics. It's true that it could simply be an effect due to the experiments lifetime, that have been running for 20 years now and where younger generations are struggling to come up with ideas not yet explored. I can speak less from the perspective of theoretical physics, but it seems obvious to all those in the field that there's a proliferation of papers proposing new particles, new interactions, etc. with no real impact.

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#75
post #74

Earlier quoted context omitted.

> felt a strong sense of frustration at how modern research in particle physics is producing papers that are all identical to each other and have no true scientific impact Your comment above makes me think of Sabine Hossenfelder[1]. I'm sure you must've heard of her. I know she's somewhat of a "polarizing" figure. As a former "insider", do you think her core point stands? (Which is, the particle physics field has lar…

Yes, I know her and I agree with what she says. I also think many physicists working in the field secretly agree with her but it's a taboo to admit it openly. As an insider I can assure you that currently most analyses in experimental particle physics are a mechanical repetition of previous analyses with a few slight modifications to adapt them to the bigger statistics. It's true that it could simply be an effect due…

I see; thanks for expanding on it so honestly.

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#76

Earlier quoted context omitted.

Politicians think it's a moonshot project at finding another nuclear bomb type of thing. (None of this would ever be funded without the tenuous nuclear weapons connection.)

That doesn't sound like something one would want to do in cooperation with the entire rest of the world.

> with the entire rest of the world

Uh, did you really mean that? The "entire" rest of the world? Even Iran and North Korea?

Well, it seems the "entire rest of the world" is only the so-called "good guys", according to the current political regime funding it.

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#77
post #74

Earlier quoted context omitted.

> felt a strong sense of frustration at how modern research in particle physics is producing papers that are all identical to each other and have no true scientific impact Your comment above makes me think of Sabine Hossenfelder[1]. I'm sure you must've heard of her. I know she's somewhat of a "polarizing" figure. As a former "insider", do you think her core point stands? (Which is, the particle physics field has lar…

Yes, I know her and I agree with what she says. I also think many physicists working in the field secretly agree with her but it's a taboo to admit it openly. As an insider I can assure you that currently most analyses in experimental particle physics are a mechanical repetition of previous analyses with a few slight modifications to adapt them to the bigger statistics. It's true that it could simply be an effect due…

I am also a former CERN scientist, and while I agree with the fact that recent papers are more and more a box-checking exercise with low value, I'm concerned on how Hossenfelder misrepresent the causes of that and the situation.

You say yourself that this situation can be simply an effect due to the experiment lifetime, and I also think it's a reasonable hypothesis.

What gives me pause with Hossenfelder is that she jumps to another conclusion, without any good observation for it or without scientific approach. These conclusions seem to be fed by the easy trap of "it's a conspiracy". We know how easy it is for people to give credit to these theses and to totally overlook that some claims are, in practice, totally unrealistic (so we have thousands of new PhD students and postdocs exploring how it works every year, the majority of them leaving the field, and strangely, the very very big majority choose, for absolutely no good reason, to keep hidden the secret they saw).

I agree with some of Hossenfelder's observations, but I find her conclusions often unsubstantiated, overstating elements that are more realistically way rarer than what she described and overlooking plenty of valid hypotheses. The fact that these "great revelations" brings her viewership also fit with a slow crank-ification. The fact that she also released videos on subjects outside of her domain and that these videos contained a lot of approximation also does not give a good image of how reliable is her approach (not that it is a crime to not know something outside of your field of expertise, but it should be something that a good scientist should be fully aware of, and they should simply not do such video in the first place).

I'm not sure if there is a real "taboo" to openly agree with her, I think it is more about the fact that she destroyed herself her own reputation with bad calls and bad conclusions, and people don't really want to tarnish themselves by association.

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#78

I feel like the title is a little overdramatic. They’re not saying goodbye to the LHC, they’re upgrading it to have 10x the power.

I had to chuckle a week or so ago when I was bumbling across the internet and landed on an article that had a link to a nutjob page where the title was something like: "CERN found something so disturbing they had to shut down immediately". The nutjob article (yes, I did read it, LOL) suggested that they had found some universal truth maybe about God or aliens or something, and it scared them so much they just noped o…

One of the more popular "explanations" of the Mandela Effect is that CERN broke time somehow.

And of course there was the whole panic about them creating a black hole and destroying the world that was popular enough to make mainstream media.

Sometimes I wonder if we actually deserve science as a species.

Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#79
post #55
post #42

I was visiting CERN on one of their Open Days during the previous shutdown. This is one of the rare occasion where visitors can enter the LHC. I walked for about 500m along the beam which is remarkably small despite all its protection. Standing inside LHCb (one of the experiments where they track collisions) was one of my most awe-inspiring moments about science and technology. Photos don’t do it justice. It’s a mult…

I'm a former LHCb physicist and I worked for years in the cavern, fixing the cables you saw :) Thanks for your enthusiasm. Obviously, things seen from the inside aren't as ideal as a non-physicist person might think. There are the usual power dynamics you find in academia: PhD students and postdocs exploited to do service and technical work instead of independent research, careerism, researchers who have to worry mor…

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Re: CERN bids farewell to the LHC and enters Long Shutdown 3

#80
post #77
post #74

Earlier quoted context omitted.

Yes, I know her and I agree with what she says. I also think many physicists working in the field secretly agree with her but it's a taboo to admit it openly. As an insider I can assure you that currently most analyses in experimental particle physics are a mechanical repetition of previous analyses with a few slight modifications to adapt them to the bigger statistics. It's true that it could simply be an effect due…

I am also a former CERN scientist, and while I agree with the fact that recent papers are more and more a box-checking exercise with low value, I'm concerned on how Hossenfelder misrepresent the causes of that and the situation. You say yourself that this situation can be simply an effect due to the experiment lifetime, and I also think it's a reasonable hypothesis. What gives me pause with Hossenfelder is that she j…

What's your opinion on Beatriz VIllarroel and her experiments on transient traces in plates?
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