## Thursday, December 06, 2018

### Hossenfelder's pathetic attack against CERN's future collider

Sabine Hossenfelder became notorious for her obnoxiously demagogic and scientifically ludicrous diatribes against theoretical physics – she effectively became a New Age Castrated Peter Woit – but that doesn't mean that she doesn't hate the rest of particle physics.

Her latest target is CERN's new project for a collider after the LHC, the Future Circular Collider (FCC), an alternative to the Japanese linear ILC collider and the Chinese circular CEPC collider (the Nimatron).

This is just a 75-second-long FCC promotional video. It shows just some LHC-like pictures with several of the usual questions in fundamental physics that experiments such as this one are trying to help to answer. The video isn't excessively original but you can see some updated state-of-the-art fashions in computer graphics as well as the visual comparison of the FCC and its smaller but more real sister, the LHC.

But when you see an innocent standard video promoting particle accelerators, Ms Hossenfelder may be looking at the very same video and see something entirely different: a reason to write an angry rant, CERN produces marketing video for new collider and it’s full with [sic] lies.

What are the lies that this video is claimed to be full of? The first lie is that the video asks what is 96% of the Universe made of. Now, this question is listed with the implicit assertion that this is the question that the people behind this project and similar projects would help to answer. It's what drives them. No one is really promising that the FCC will answer this question.

The figure 96% refers to the dark energy (70%) plus dark matter (26%) combined. Hossenfelder complains:
Particle colliders don’t probe dark energy.
Maybe they don't but maybe they do. This is really a difficult question. They don't test the dark energy directly but whenever we learn new things about particles that may be seen through particle accelerators, we are constraining the theories of fundamental physics. And because the theories' explanation for particular particles and for dark-energy-like effects are correlated in general, the discoveries at particle accelerators generally favor or disfavor our hypotheses about dark energy (or whatever replaces it), too.

My point is that at the level of fundamental physics, particle species and forces are interconnected and cannot quite be separated. So her idea that these things are strictly separated so that the FCC only tests one part and not the other reflect some misunderstanding of the "unity of physics" that has already been established to a certain extent. Also, she writes:
Dark energy is a low-energy, long-distance phenomenon, the entire opposite from high-energy physics.
This is surely not how particle physicists view dark energy. Dark energy is related to the energy density of the vacuum which is calculable in particle physics. In the effective field theory approximation, contributions include vacuum diagrams – Feynman diagrams with no external legs. According to the rules of effective field theories as we know them, loops including any known or unknown particle species influence the magnitude of the dark energy.

For this reason, the claim that the dark energy belongs to the "entirely opposite" corner of physics than high-energy physics, seems rather implausible from any competent theoretical high-energy physicist's viewpoint. The total vacuum energy ends up being extremely tiny relatively to (any of) the individual contributions we seem to know – and this is known as the cosmological constant problem. But we don't know any totally convincing solution of that problem. The anthropic explanation assuming the landscape and the multiverse where googols of possible values of dark energy are allowed is the most complete known possibility – but it is so disappointing and/or unpredictive that many people refuse to agree that this is the established final word about the question.

The right solution could include some complete separation of the dark energy from high-energy physics, as suggested by Hossenfelder. But this is just one possible category of proposals. It's surely not an established scientific fact. And there's no known convincing theory of this Hossenfelder's type.

The discovery or non-discovery of superpartners at a higher energy scale would certainly influence the search for promising explanations of the cosmological constant problem, and so would other discoveries. For example, the dark energy may be due to quintessence and quintessence models may predict additional phenomena that are testable by the particle colliders. None of the findings are guaranteed to emerge from the FCC but that's how experiments usually work. We don't really know the results in advance, otherwise the experiment would be a waste of time.
What the FCC will reliably probe are the other 4%, the same 4% that we have probed for the past 50 years.
Indeed, a collider may only be promised to test the visible matter "reliably". But science would get nowhere if it were only trying to probe things that can be probed "reliably". That statement is very important not just for science. When Christopher Columbus sailed to the West, he claimed to reach India from the other side or stuff like that. But he couldn't promise them to reach India reliably. After all, indeed he had found another continent that almost covers the whole space between the North Pole and South Pole and prevents you from sailing from Europe to India in this direction.

But that didn't mean that Columbus' voyage was a waste of resources, did it? It is absolutely essential for the scientific spirit to try lots of things, both in theoretical and experimental science, whose successful outcome is not guaranteed, probes of things that are "unreliable". Scientists simply have to take the risk, to "experiment" in the colloquial sense.

It's truly ironic that Sabine Hossenfelder has been "created" as an appendix of Lee Smolin, her older fellow critic of science, who always claimed that science needed to fund much more risky directions and stuff like that (needless to say, the "most courageous directions" were meant to represent a euphemism for cowardly crackpots such as himself). Where does it end when Lee Smolin pulls a female clone from his dirty aß and she drags all the anti-scientific gibberish he used to emit through several more years of evolution? What does she do with all the "courage" that Smolin's mouth – not behavior – was full of? And with the value of risk-taking? She says that only experiments with a "reliable" outcome should be funded! Isn't it ironic?

The next collider, and even the LHC in the already collected data or in the new run starting in 2021, may learn something about dark matter. If the dark matter is a light enough neutralino, the LHC or the next collider is likely enough to see it. If the dark matter is an axion, the outcome may be different. But if we won't try anything, we won't learn anything, either. Indeed, her criticism of the tests of dark matter theories is identical:
What is dark matter? We have done dozens of experiments that search for dark matter particles, and none has seen anything. It is not impossible that we get lucky and the FCC will produce a particle that fits the bill, but there is no knowing it will be the case.
A malicious enough person could have made the exact same hostile and stupid comment before every important experiment in the history of science. There was no knowing that Galileo would see anything new with the telescopes. Faraday and Ampere and Hertz and others weren't guaranteed to see any electromagnetic inductions, forces, electromagnetic waves. The CERN colliders weren't certain to discover the heavy gauge bosons in the 1980s and the Tevatron didn't have to discover the top quark. The LHC didn't have to discover the Higgs boson, at least not by 2012, because its mass could have been less accessible. And so on.

Does it mean that experiments shouldn't ever be tried? Does it mean that there is a "lie" in the FCC video? No. With Hossenfelder's mindset, we would still be jumping from one palm to another and eating bananas only. Another "lie" is about the matter-antimatter asymmetry:
Why is there no more antimatter? Because if there was, you wouldn’t be here to ask the question. Presumably this item refers to the baryon asymmetry. This is a fine-tuning problem which simply may not have an answer. And even if it has, the FCC may not answer it.
The answer to the question "because you wouldn't be here" may be said to be an "anthropic" answer. And it's a possible answer and a true one. But it doesn't mean that it is the answer in the sense of the only answer or the most physically satisfying answer. In fact, it's almost certain that Hossenfelder's anthropic answer cannot be the deepest one.

Why? Simply because every deep enough theory of particle physics does predict some baryon asymmetry. So the very simple observed fact that the Solar System hasn't annihilated with some antimatter is capable of disproving a huge fraction of possible theories that people could propose and that people have actually proposed.

Her claim that it is a "fine-tuning problem" is implausible. What she has in mind is clearly a theory that predicts the same amount of baryons and antibaryons in average – while the excess of baryons in our Universe is a statistical upward fluctuation (she uses the word "fine-tuning" which isn't what physicists would use but the context makes her point rather obvious). But one can calculate the probability of such a large enough fluctuation (seen all over the visible Universe!) for specific models and the probability is usually insanely low. For that reason, the very theory that predicts no asymmetry in average becomes very unlikely, too. By simple Bayesian inference, a theory that actually explains the asymmetry – that has a reason why the mean value of this asymmetry is nonzero and large enough – is almost guaranteed to win! Fundamental physicists still agree that you should better obey the Sakharov conditions (needed for an explanation of the asymmetry to exist).

It is rather transparent that she doesn't understand any of these questions. She doesn't understand how scientists think. She misunderstands the baryon asymmetry and tons of other technical topics but she also misunderstands something much more universal and fundamental – how scientists think and infer in the presence of some uncertainty which is almost omnipresent. Whenever there's some anomaly or anything that doesn't add up, but it plausible with a tiny probability, she just calls it "fine-tuning", throws "fine-tuning" at the problem, and concludes that there's nothing to explain. Sorry, this is not how a scientist thinks. If this attitude had been adopted by everyone for centuries, science wouldn't have made any progress at all. Visible enough anomalies simply do require genuine explanations, not just "it's fine-tuning and fine-tuning is always OK because naturalness is beauty and beauty is rubbish", which is Hossenfelder's totally flawed "methodology" in all of physics.

On top of that, she repeats her favorite "reliability" theme: "And even if it has, the FCC may not answer it." Right, the FCC may fail to answer one question or another, and it will almost certainly fail to answer most questions that people label as questions with a chance to be answered. But the other part of the story is that the FCC also may answer one of these questions or several of these questions.

Note that Hossenfelder only presents one possible scenario: science will fail to answer the questions. She never discusses the opposite possibility. Why? Because she is a hater of science who would love science to fail. Every time science learns something new, vitriolic science haters such as Ms Sabine Hossenfelder or Mr Peter Woit shrink. After every discovery, they realize that they're even more worthless than previously thought. While science makes progress, they can only produce hateful tirades addressed to brainwashed morons. While the gap is getting larger and deeper, and more obvious to everybody who watches the progress in science, the likes of Ms Hossenfelder escalate their hostility towards science because they believe that this escalation will be better to mask their own worthlessness.

The fact that the FCC has a chance to answer at least one of these questions is much more important than the possibility that it won't answer one of them or any of them.

Hossenfelder also claims that the FCC won't probe how the Universe began because the energy density at the FCC is "70 orders of magnitude lower". This is a randomly picked number – she probably compared some FCC-like energy with the Planck energy. But the statement about the beginning of the Universe doesn't necessarily talk about the "Planck time" after the Big Bang. It may talk about somewhat later epochs. But if the FCC has a higher energy than the LHC, it will be capable of emulating some processes that are closer to the true beginning than the processes repeated by the LHC.

She has also attacked the claims about the research of neutrinos:
On the accompanying website, I further learned that the FCC “is a bold leap into completely uncharted territory that would probe… the puzzling masses of neutrinos.”

The neutrino-masses are a problem in the Standard Model because either you need right-handed neutrinos which have never been seen, or because the neutrinos are different from the other fermions, by being “Majorana-particles” (I explained this here).
The FCC is relevant because new observations of the neutrino physics are possible – whether right-handed neutrinos or the rest mass of neutrinos (whether they are Dirac or Majorana) or new species of neutrinos etc. – and, on top of that, the very fact that the neutrino masses are nonzero may be viewed as physics beyond the Standard Model.

Why is it so? Because the neutrino masses, at least the Majorana ones, can't come from the Yukawa interactions. The term $$y h \bar \nu \nu$$ isn't an $$SU(2)$$ singlet because the term contains the product of three doublets, an odd number. You need dimension-five operators. Those are non-renormalizable. A theory with them breaks at some energies. At that energy scale, some new phenomena must kick in to restore the consistency of the theory.

Alternatively, Dirac masses could come from renormalizable Yukawa dimension-4 operators but the new right-handed neutrinos components may be said to be beyond the Standard Model. Some new interactions could be measured etc. Whatever is true in Nature, the FCC may clearly produce neutrinos and detect them in the form of the missing energy, like the LHC. It's unreasonable to attack the statement that the new collider would allow to test neutrinos in a new regime.
We presently have no reliable prediction for new physics at any energy below the Planck energy. A next larger collider may find nothing new. That may be depressing, but it’s true.
But the FCC video is simply not saying that we are guaranteed to get such answers. The big desert between the Standard Model and (nearly?) the Planck scale has always been a possibility. If we had the "duty" to have a reliable prediction of some new physical phenomenon at an intermediate energy scale, it would have to be found by theoretical particle physicists or similar folks.

But curiously enough, she's hysterically fighting against that (theoretical) part of the research, too. To summarize, she is fighting against particle, fundamental, or high-energy physics in any form. She hates it, she hates people who are asking questions, she hates people who are proposing possible answers, and she hates the people who do any work – theoretical or experimental work – that may pick the right answers or at least favor or disfavor some of them.

Nevertheless, due to the extreme political correctness, this absolute hater of science who doesn't do anything except for lame efforts to hurt the image of science is sometimes presented as a physicist by the popular media. She is nothing of the sort.