B Sabine Hossenfelder on the search for new particles

[kodama]

Let's consider the proposed particles that she lists in her article:

This is a very mixed collection.

Giant magnons and skyrmions actually exist, as quasiparticles in condensed matter.

A preon is essentially any sub-quark particle. I think most lay people would consider this a quite reasonable concept, on the general principle that humanity has repeatedly discovered deeper layers of structure in matter.

A magnetic monopole would be a particle with "magnetic charge"; a dyon, any particle with both electric charge and magnetic charge. As concepts, these may also seem reasonable, given that we have electric fields and magnetic fields, and electrically charged particles that generated the electric fields.

Wimps are weakly interacting massive particles, a candidate for the dark matter that seems to have mass but doesn't otherwise do much; and wimpzillas, simps, wisps, and fips are all variations on this concept. Perhaps the names are not very dignified. But we could translate them as follows:

Wimp = dark matter particle that is massive but interacts weakly
Wimpzilla = dark matter particle that is extremely massive but interacts weakly
Simp = dark matter particle that is massive and interacts strongly
Wisp = dark matter particle that is light and interacts weakly
Fip = "feebly interacting particle" that may or may not be dark matter

My point is that these are all variations on the same hypothesis, "dark matter particle", with slightly different properties and parameter values.

A "macro" seems to be any larger-than-microscopic object that could constitute dark matter - it need not be a particle at all, and can even be made of ordinary matter, so long as it's dark.

Then we get to some concepts whose definition and motivation is a little more technical.

The axion was originally postulated to explain why the theta parameter of QCD is zero. Now it refers to a much broader class of possible particles whose exact definition is unclear to me, but which I suppose have a dynamics similar to the axion. Hossenfelder also mentions the "flaxion", which like all the variations on "WIMP", is still just an axion, but one that also does some other things (related to "flavor").

We know about three types of neutrino; a sterile neutrino would just be another one, one that didn't interact with any standard model forces.

Sfermions are supersymmetric partners of fermions. Not a very common word, compared to names of specific superpartners like squark, slepton, gravitino, and so on.

All those were a little technical, but still fairly common. Finally, we have a collection of rarer terms - erebon, acceleron, cornucopion, maximon, branon, chameleon, cuscuton, Planckon. (The unparticles are somewhere between "technical but common" and "rare", I guess.)

Anyway, what do we learn from this review? That the "undiscovered hypothetical particles" fall into some very different groupings. Some represent quite straightforward concepts ("sub-quark particle", "particle with magnetic charge", "dark matter particle"). Others represent concepts that are more esoteric, but popular with theorists, and which are considered well-motivated. Finally, we have concepts that represent highly specific scenarios that are only studied by a few people.

x17 and Z' is not on the list

 

[ohwilleke]

I gave today as an example. 0 of 25.
Will do it for a week, just for fun.

You missed at least one: https://arxiv.org/abs/2209.14882 (proposing a hypothetical new light Higgs boson in a new Higgs doublet to facilitate the possible existence of sub-GeV hypothetical DM particles in a thermal freeze out model of DM particle creation).

Who are "we"?

We is the collective community of physicists with power to govern how its institutions operate, i.e. the physics community.

 

[ohwilleke]

what about publications in peer review journals.

The problem is not mostly that scientists end up relying on a lot of published papers that don't add value. The problem is that physicists waste a lot of time studying dubious models that would be better spent elsewhere. This is a problem whether the papers get published or not. The time spent writing the papers and the time by others reading the papers (who waits until publication to read papers anymore?), and not the make up of what gets actually published, is what causes the harm.

If there was less of an incentive to work on ill-motivated BSM particles, this brain power and time and the related resources available to the physics community would be spent on other research that is more likely to be fruitful.

Also, most of the resources spent searching for hypothetical particles that have no real motivation to exist in the first place on the experimental side does end up producing published papers. ATLAS and CMS kick out a fair number of these "we looked for hypothetical particle X and there were no statistically significant deviations from the SM" papers every month.

 

[Vanadium 50]

We is the collective community of physicists with power to govern how its institutions operate, i.e. the physics community.

I think at least some of the people who put themselves in the "we" category might be better characterized as "they". Just sayin'.

 

[strangerep]

Physics is like sex, it might give practial results but its not why we do it

Spoiler

Unkind people might say (theoretical) physics more like wanking...

Spoiler

... and now I wait to see if this will get past Berkeman...

 

[strangerep]

If she was looking to improve the situation, she should have made more specific criteria for how she would rate "promising" vs. "unpromising" [...]

She has done this more than once in the past. In essence, she emphasizes the need to resolve inconsistencies between theory and experiment, or within theories that are already reasonably well supported by experiment. She has given several examples in earlier blog postings.

But most people never seem to remember that.

 

[PAllen]

I think she does in a way. Her argument echoes what Feynman noted decades ago: because of the success of the Standard Model, theory is driving experiment rather than the other way around. To her, all these hypothetical particles are largely a waste of time and money, theoretical particle physics is a dead field until a real new experimental result is discovered suggesting where and how to modify the Standard Model, and a dead field shouldn't be allocated so many resources. Woit noted in his blog post that the LHC ruled out "a lot of bad theory." Hossenfelder would argue those bad theories shouldn't have even been considered in the first place.

But where would this new result come from, if not from something like the LHC?

 

[PAllen]

She has done this more than once in the past. In essence, she emphasizes the need to resolve inconsistencies between theory and experiment, or within theories that are already reasonably well supported by experiment. She has given several examples in earlier blog postings.

But most people never seem to remember that.

One of the things she rejects as a good research area is the origin of matter/antimatter asymmetry. We should just chalk it up to initial conditions. This one I find quite absurd.

"Baryon Asymmetry and The Horizon Problem
These are both finetuning problems that rely on the choice of an initial condition, which is considered to be likely. However, there is no way to quantify how likely the initial condition is, so the problem is not well-defined."

from: "http://backreaction.blogspot.com/2019/01/good-problems-in-foundations-of-physics.html"

 

[malawi_glenn]

You missed at least one: https://arxiv.org/abs/2209.14882 (proposing a hypothetical new light Higgs boson in a new Higgs doublet to facilitate the possible existence of sub-GeV hypothetical DM particles in a thermal freeze out model of DM particle creation).

That is not a "2sigma-anomaly" paper in my book. It is a Dark Matter paper.

We is the collective community of physicists with power to govern how its institutions operate, i.e. the physics community.

When you write "we" you include yourself. And I do not think writing regularly on physicsforums counts...

The time spent writing the papers and the time by others reading the papers (who waits until publication to read papers anymore?), and not the make up of what gets actually published, is what causes the harm.

Is there really "harm" going on? As I wrote, I think this is overexaggerated. Sabine makes many claims with no backup like "talk to many particle physicsists in private..." and so on. There is no evidence, just anectotical observation on her behalf (and also on your).

ATLAS and CMS kick out a fair number of these "we looked for hypothetical particle X and there were no statistically significant deviations from the SM" papers every month.

That is true, but that is also powerful in a sense because the bounds can be made very strong for a vast majority of these goofy models in just a single measurement. This can in turn be the "cure" for these so called "anomaly" papers. These measurements are also quite model independent. How else are they going to find new particles or something deviating from the SM?
Let's go back to the LEP experiment. No new particle was found there, they basically did precision tests of the SM (like better W and Z mass etc). No Higgs. The urge of finding Higgs was very strong since there is a problem with having massive gauge bosons in a model. But where was Sabine back then? Why not just say that the entire framework of gauge symmetry in QFT is wrong in the first place and that particle physicsts need to spend their brain power elsewhere?

You think now since Higgs was discovered at LHC, they should just turn off the machine? Will that solve the problems in particle physics?

My personal view is that the most crucial research problem to solve in particle physics today is the origin of neutrino masses since it is not compatible with the SM. Neutrino masses are per definiton BSM physics.

 

[PAllen]

One of the things she rejects as a good research area is the origin of matter/antimatter asymmetry. We should just chalk it up to initial conditions. This one I find quite absurd.

"Baryon Asymmetry and The Horizon Problem
These are both finetuning problems that rely on the choice of an initial condition, which is considered to be likely. However, there is no way to quantify how likely the initial condition is, so the problem is not well-defined."

from: "http://backreaction.blogspot.com/2019/01/good-problems-in-foundations-of-physics.html"

And another, indicative of idiosyncratic interpretations of her own principles:

"
The Strong CP Problem
Is a naturalness problem, like the Hierarchy problem, and not a problem of inconsistency.
"
To me, flat out wrong. The existing best theory predicts x should occur. Experiment says it doesn't. This is an inconsistency between theory and experiment, the most important type of inconsistency to resolve.

 

[nuuskur]

I have mixed feelings.

Is she painting a(n inaccurate) caricature of particle physics and then proceeds to criticize its flaws? She said she used to be a particle physicist, but the way she expresses herself is like she was the end-all be-all scientist in that field and she would know Anything about it. I would not have expected such arrogance from a (former?) scientist.

 

[malawi_glenn]

I would not have expected such arrogance from a (former?) scientist.

https://www.fias.science/en/fellows/detail/hossenfelder-sabine/

 

[nuuskur]

I think it is incorrect to reason that: conjecturing particle X has been useless, because experiments have not yielded evidence for its existence.

I certainly don't believe that ALL particle physicists make up completely random conjectures (analogous to the twelve-legged spider) in order to write trivial nonsense papers about it. Mathematics, for instance, is cumulative and I'm sure (particle) physics has this property as well. Rarely does research start from a mostly clean slate.

 

[malawi_glenn]

I certainly don't believe that ALL particle physicists make up completely random conjectures (analogous to the twelve-legged spider) in order to write trivial nonsense papers about it.

Not even the majority, not even a large percentage either.

 

[pinball1970]

https://www.fias.science/en/fellows/detail/hossenfelder-sabine/

That was unexpected.

 

[artis]

I think these problems that Sabine talk about are fundamental to all complex fields. Look at any successful R&D lab or company, they will have x10 the amount of failed work as compared to the working ones.

Another example is patents, some 1% of all of them ever see daylight and ever get used.

That being said I think Sabine is at least part correct, because just like large companies and patents, it has became a game for them, they make thousands of patents each year where they know most of them are useless and will sit on a shelf, but they sort of put their foot in the door so that in case any other comes up with a similar but better idea in the future they can then claim in court that their intellectual property has been used and get some money.

In particle physics this would be analogous to what other users already commented that many physicists are pressed to earn credentials and money therefore they have to come up with something and can't just spend decades in silence trying to find that which in the end might not be there after all.But everything is easy from the start, recall the start of 20th century? All you had to do is make a vacuum and fire up an electron gun and produce some electrons , then hit an anode produce some photons and it was a "wow" moment, you could write articles about it, use it, patent it and the bonus is they were real particles that could be detected and put to use in industry etc, all were happy.
Nowadays any small incremental find is much harder and almost impossible to put to direct use.
Like we don't expect to use the higgs in industry or solve global warming with quark masses etc.
In theory in a free society you can't really command what others should spend their time researching, the only question then becomes if it's done with public funds, do we put some stronger checks in place to make sure the money is spent as best it can.
That being said on average I believe far more money is wasted on shady infrastructure and social program deals where the return on investment is just as bad as that in string theory.

 

[vanhees71]

She has done this more than once in the past. In essence, she emphasizes the need to resolve inconsistencies between theory and experiment, or within theories that are already reasonably well supported by experiment. She has given several examples in earlier blog postings.

But most people never seem to remember that.

The problem is that we don't have inconsistencies between theory and experiment concerning the Standard Model. The pattern usually is that there are some $4\sigma$ discrepancies with the standard model or some bump in some cross-section data, which after a while go away when the experimentalist got it to $>5 \sigma$. Another example is the muon $g-2$. There the before thought to be correct "theoretical prediction" (based on extrapolation of $e^+ e^- \rightarrow \text{hadrons}$ data to the corresponding hadronic off-shell contributions to $g_{\mu}$ via dispersive methods) has turned out to be most probably not accurate, which has been figured out by lattice-QCD calculations (the Budapest-Wuppertal group was first, but it's now consolidated by other independent lattice calculations). I'd say that's the usual way science works, and there's nothing to criticize about it. Also that there are many "theoretical speculations" like SUSY (only the minimal extension of the SM has been tested at the LHC and seems indeed not to be the answer for physics beyond the SM) or even string theory (without any relation to observables yet) is no argument against all this scientific activities since that's also how science works: You make a conjecture which can be tested by experiment, which then decides whether it's a valid conjecture or not. What I find a bit embarrasing, and here I agree with Hossenfelder, are the many completely weird speculations popping up like crazy on arXiv like the ones, e.g., after the apparent "faster-than-light neutrinos" of the OPERA collaboration. This went as far as claiming that the very basics of relativity were wrong, much like the usual crackpotery found by anti-Einstein afficionados sent to you via e-mail spam from time to time.

I also agree with Hossenfelder that it is very unlikely that a "grand new theory" or even a "theory for everything", solving the real physics problems (for me that's indeed basically only the quantum theory of gravitation), can be found by pure mathematical reasoning but that some new empirical input is really needed, i.e., some real discrepancy between the Standard Model and experiment, but as I mentioned above, there's no solid such observation yet. However, I don't see what else the HEP community should do than what she does, i.e., making ever better experiments as are done in the near future with the just upgraded LHC collider and the associated detectors. There are also no empirical hints at any quantum effects related to the gravitational interaction, which makes it the more difficult to find a right idea about this too. Here, I don't have the slightest idea, how this dilemma might be solved since also here GR seems to survive all tests under ever more extreme conditions, and all these tests naturally refer to macroscopic astronomical objects like neutron stars and black holes, where it is very unlikely to find hints at effects at the quantum level.

Where I completely disagree is that a solution should be to use even less solid philosophical quibbles about some pseudo-problems with the "foundations of Q(F)T". There are, of course, mathematical problems with Q(F)T, which are well worth to be investigated further, but to claim that there's a measurement problem or that one should derive Born's rule from something else, is completely misguided. I don't see any problems with these apparent "foundational problems". There's not the slightest hint that QT fails in describing any experiment today.

 

[malawi_glenn]

The problem is that we don't have inconsistencies between theory and experiment concerning the Standard Model

Neutrino masses says hello

 

[mfb]

Woit's page links to another page by Hossenfelder
http://backreaction.blogspot.com/2022/09/ive-said-it-all-before-but-here-we-go.html

That article is as absurd as the Guardian article. It even contradicts itself:

So my recommendation is that theory development should focus on resolving inconsistencies, and stop wasting time on pseudo-problems. Real problems are eg the lacking quantization of gravity, dark matter, the measurement problem in quantum mechanics, as well as several rather technical issues with quantum mechanics (see the above mentioned list).

Most of the models she criticizes are trying to do that. The others are trying to solve actual problems she dismissed as "pseudo-problems" for mysterious reasons.

More importantly, everyone can see that nothing useful is coming out of particle physics, it’s just a sink of money. Lots of money. And soon enough governments are going to realize that particle physics is a good place to save money that they need for more urgent things.

So everyone can see it, apart from everyone involved in it? Everyone can see it but we need Hossenfelder drawing attention to it?

If she writes these articles to help particle physicists, as she claims, why choose the Guardian? It's obviously not done to reach particle physicists. It's done to reach the largest audience she can get - people who cannot see through all the misrepresentations, half-truths, ambiguous statements and other problematic claims that make up the majority of the articles. The target audience for her books, which is conveniently mentioned at the end of the article.

I yet have to find a particle physicists who actually engaged with the argument I made.

That's an obvious lie, unless we let her dismiss any criticism as "that's not an argument", as she tries to do here:

The only “arguments” I hear from particle physicists are misunderstandings that I have cleared up thousands of times in the past.

So she actually admits herself that there is some discussion. But isn't it curious that she doesn't mention anyone who agrees with her? Or everyone only does so in secret? That's a pretty big conspiracy we must be in.

They almost all attack me rather than my argument.

Oh no, we call out people for writing obvious lies!

 

[nuuskur]

This pretense that she thoroughly understands particle physics and keeps putting words in others' mouths leaves a bad taste. It's more like a popularity contest. Inciting culty behaviour, I don't like it :(

..and I have this reaction when I barely know anything about her. It's not fair to prematurely judge, sure, but how seriously does she expect scientists and other relevant experts to take her when she weaves a narrative based on some cherry picked data? Worse, she is presenting to an audience of whom most are not equipped to critically assess her claims. Forming an echo chamber.

Being as uncharitable as I can for a moment - it's not important to her that she reach the experts at all. More followers, more potential people that buy her book(s). It definitely takes much less effort convincing people without some form of mathematical training.

 

[PAllen]

I'll add that years ago I used to have very good opinion of Hossenfelder, and still enjoy some of her papers. However, as she began seeking video stardom, she has more and more set a tone of poking at physicists who disagree with her not just critiquing theory or methods (while bemoaning ad hominem attacks on herself). The video that first turned me off was one where she said the LIGO team was doing crappy physics (her words exactly, in a public audience video) and that we should not believe what they say about their methodology in relation to the gamma ray burst coincidence event. (Also, strongly criticizing the Nobel award for any aspect of the LIGO work).

 

[vela]

So everyone can see it, apart from everyone involved in it? Everyone can see it but we need Hossenfelder drawing attention to it?

She's saying everyone, including the people involved in it, can see it, but particle physicists, both theoretical and experimental, have a vested interested in perpetuating the system as it keeps them employed.

If she writes these articles to help particle physicists, as she claims, why choose the Guardian?

I don't think she's trying to help particle physicists. If anything, she's arguing they need to go away and focus on what she considers real problems in physics. Her attitude and approach does come across as incredibly arrogant, and I can see why it rubs people the wrong way.

 

[PAllen]

I have mixed feelings.

e would know Anything about it. I would not have expected such arrogance from a (former?) scientist.

She is certainly a practicing productive physicist. She still averages 4 or so papers published in reputable peer reviewed journals (phys. rev, phys letters, and similar stature) per year.

 

[Vanadium 50]

Neutrino masses says hello

I think this is a bad example. The idea that "the SM predicts zero neutrino mass" came about only after they were known to be non-zero. I have another post here - somewhere - where I cite some before-and-after papers on this.

A better example of an unexplained phenomenpn is the neutrality of atoms. You can argue that the Higgs Yukawas, and CKM/PMNS matrix elements just "are what they are" with no better explanation than "well, they have to be something". But why are atoms neutral?

You can "explain" that by saying, it's because the electron has charge -1, the u-qaurk +2/3 and the d-quark -1/3, but again why? You can dig a little deeper, and conclude that the problem is not with weak isospin (because the generators are matrices) but with weak hypercharge (because a U(1) allows any real number as its charge): if quarks and leptons live in different representations of the SM, there should be no reason that their weak hypercharges be in small integer ratios with each other. (Ratio is 0:1:2:4:6)

Atoms are neutral to about 28 decimal places. You have two options - either this is just a 28 figure coincidence, or there is a reason for this. There is, as far as I know, exactly one idea for why this is: that the U(1) comes from breaking of a larger symmetry - for instance, SU)5) or SO(10). However, every group big enough to explain atomic neutrality also has additional particles. Should we:

1. Look for them?
2. Not look for them.

 

[mitchell porter]

if quarks and leptons live in different representations of the SM, there should be no reason that their weak hypercharges be in small integer ratios with each other. (Ratio is 0:1:2:4:6)

Anomaly cancellation?

 

[ohwilleke]

And another, indicative of idiosyncratic interpretations of her own principles:

"
The Strong CP Problem
Is a naturalness problem, like the Hierarchy problem, and not a problem of inconsistency.
"
To me, flat out wrong. The existing best theory predicts x should occur. Experiment says it doesn't. This is an inconsistency between theory and experiment, the most important type of inconsistency to resolve.

This is a misunderstanding of what the StrongCP problem is. The relevant equations of QCD would naturally have a place to put a parameter theta to describe CP violation, but the experimentally measured value of theta in a version of the equations to include this term at all, is zero (i.e. no CP violation).

The best existing theory does not predict that CP violation should occur. It merely observes that it could occur and does not. This is not a true problem.

The naturalness problem and the hierarchy problem are similar. These problems wonder why physical constants like the Higgs boson mass, have the values that they are physically measured to have, based upon the completely arbitrary assumption that certain kinds of physical constants ought to have a value on the order of one, rather than having very large or very small values.

But, these arguments are total bullshit. Nature faces no restriction on what value physical constants should take. The values that are measured do not contradict any laws of physics, they simply aren't what some misguided physics theorists think they should be in a theory that is obviously not right. Arguments that the laws of physics and their parameters SHOULD have values different than what they are are category errors, not parameters that misunderstand the nature of what science is.

 

[PAllen]

This is a misunderstanding of what the StrongCP problem is. The relevant equations of QCD would naturally have a place to put a parameter theta to describe CP violation, but the experimentally measured value of theta in a version of the equations to include this term at all, is zero (i.e. no CP violation).

The best existing theory does not predict that CP violation should occur. It merely observes that it could occur and does not. This is not a true problem.

The naturalness problem and the hierarchy problem are similar. These problems wonder why physical constants like the Higgs boson mass, have the values that they are physically measured to have, based upon the completely arbitrary assumption that certain kinds of physical constants ought to have a value on the order of one, rather than having very large or very small values.

But, these arguments are total bullshit. Nature faces no restriction on what value physical constants should take. The values that are measured do not contradict any laws of physics, they simply aren't what some misguided physics theorists think they should be in a theory that is obviously not right. Arguments that the laws of physics and their parameters SHOULD have values different than what they are are category errors, not parameters that misunderstand the nature of what science is.

I don’t look at it this way. Zero is not simply a parameter value, it is the absence of a phenomenon that could have any strength, for no known reason. Further, observed baryon asymmetry make one wonder why this is so. Thus, a credible theory that had strong force CP violations in an early era, with suppression later would solve two real problems at once. The whole notion of a self appointed arbiter of what problems are real is absurd.

 

[strangerep]

[Hossenfelder music video]... That was unexpected.

Yes -- she also composes music and has a separate youtube channel for that, iirc.

I like some of her music videos that I've chanced to watch (e.g., "The End of the World as We Know It" near the start of the panademic). But I don't bother visiting her music channel.

In any case, so what if she has other extracurricular non-physics interests? I've noticed plenty of people who seem unexpected peculiar if candidly observed in the wild.

 

[pinball1970]

In any case, so what if she has other extracurricular non-physics interests? I've noticed plenty of people who seem unexpected peculiar if candidly observed in the wild.

It was not a criticism it just took me by surprise.
Not at all what I expected when the video started.

 

[Vanadium 50]

Anomaly cancellation?

That's an effect, not a cause.