## Wednesday, June 14, 2017

### LHC null results haven't changed the qualitative big picture in HEP

Two years ago, I wrote about relaxions, a new way to create awkward theories – that could be said "to be rather natural according to some criteria but not all criteria" – which are capable of "explaining" the existence of large numbers in physics.

One starts with a large, but only logarithmically large, number of fields and assigns somewhat exotic values of charges under a $$U(1)$$ gauge group – and yes, it has to be an Abelian group which may be considered a damning flaw of the whole paradigm. Consequently, one finds that there exists a scalar boson with a periodic range of values whose periodicity is "exponentially large" in the number of elementary fields we have used.

Backreaction discusses those papers and some of their recent followups under the new brand, Clockworks. It is an OK idea – which is probably irrelevant in physics but has some chance to be relevant – but it can in no way be classified as the "#1 idea" of a decade or something big like that.

Instead of discussing the somewhat modest and vague idea again, let me express my disbelief about a general statement made at Backreaction.

Sabine Hossenfelder wrote:
But there hasn’t been a big, new trend since the LHC falsified everything that was falsifiable. It’s like particle physics stepped over the edge of a cliff but hasn’t looked down and now just walks on nothing.
Wow. So the "LHC has falsified everything that was falsifiable", we hear. So particle physics as we knew it is probably dead by now. What is this sentence supposed to say?

Aside from several suggestive hints of new physics, e.g. those challenging lepton universality, the results from the LHC have been compatible with the Standard Model – the complete one which has included the Higgs boson and since the 2012 discovery, it should be considered a part of the "old physics".

So it means that the Standard Model's range of validity or usability is at least a bit greater than what an average particle physicist believed a few years ago. The range of validity may keep on growing. But this growth may also abruptly stop at any moment in the future if and when new physics is discovered.

What has the LHC falsified? It has only falsified theories that could have been falsified by now, i.e. theories and models that made a firm prediction that effects deviating from the Standard Model may be experimentally proven within 35 inverse femtobarns of the proton-proton collision data at the center-of-mass energy of $$13\TeV$$. That's the right clarification of the sentence.

The LHC has only falsified what it could have falsified by the finite amount of data at the limited energy available as of today.

In other words, once you clarify the demagogically simplified sentence by Hossenfelder, it turns into an absolutely vacuous and useless tautology and you realize that there is nothing particularly "fatal" about the current moment in the history of physics. But the very point of her and similar demagogues' oversimplification is that they want to deceive their readers, and because many of their readers are very gullible, they get deceived all the time.

Her statement is just like the proposition: Life has shown that all people who are still around and who could have died are immortal.

Is that true? Well, it isn't. The fact that you're alive now doesn't mean that you are immortal, i.e. that you can never die. Exactly in the same way, the fact that the Standard Model hasn't been falsified or proven incomplete as of now doesn't mean that it is the precise theory of Nature forever. And on the contrary, if a theory or paradigm doesn't imply sharp, discoverable predictions of new effects in the dataset that the LHC has collected, it just doesn't mean that it is unfalsifiable.

The null results of the LHC – which are compatible with the Standard Model – bring us some information about Nature, whether you like it or not. At the same moment, the information is less exciting and "contains fewer bytes" because it may be summarized by saying that things continue to be the same as what was established previously.

Before the LHC started, physicists could have already imposed lower bounds on the masses on hypothetical new particles, upper bounds on the interaction strength of hypothetical new interactions, and so on. What the LHC has done was to change the numbers so that the statements that can be made now are stronger than those that were possible 10 years ago. The lower bounds on the new particles' masses have grown. The upper bounds on the new forces' interaction strength have been lowered. But all these things are quantitative adjustments. You don't really need to learn intellectually demanding new things – relatively to what you should have learned before 2008 – if you want to understand the observations done at the LHC. You may call it a relief, you may call it sad, you may call it a nightmare scenario, but regardless of the emotional labels, it's a fact. And it's a new fact and scientists are ultimately supposed to find them, whatever they turn out to be.

So where does it leave particle physics? Particular models, especially the ambitious theories predicting new phenomena that should have been around the corner, i.e. discovered soon, have been killed. More careful models that predict new phenomena for the LHC but don't try to claim that they must be around the corner could have been either disfavored, or somewhat favored, relatively speaking, because they were disfavored less than their bolder competitors.

But again, the impact of the null results from the LHC on the theories, models, and ideas may be summarized as a bunch of technicalities, elimination of all the models that were too specific, too ambitious, and too impatient. And some adjustments of numbers – relative degrees of faith that physicists assign to one theory, model, or idea or another.

Because after the Higgs discovery, the LHC hasn't made any qualitative, game-changing discovery of new physics, the game hasn't qualitatively changed! Again, this sentence is a tautology but the likes of Hossenfelder do everything they can to convince you that this self-evidently correct tautology is actually incorrect. They want you to abandon rational thinking altogether.

So the LHC hasn't changed the qualitative landscape. And the situation is therefore analogous to what it was in 2008. If you want to do research of high-energy physics, you may still pick similar strategies as you could in 2008. You may be biased towards "easily falsifiable" theories and models. Needless to say, you still have a chance to succeed once the LHC collects a bigger amount of data – or once a hypothetical bigger future collider collects some data. $$13\TeV$$ isn't the maximum possible energy of particles in Nature and 35/fb isn't the maximum allowed integrated luminosity in Nature.

But you may also be proven wrong, just like the authors of all the "easily falsifiable" models before the recent LHC run.

Or you may abandon this fanatical desire to become famous as soon as possible and study the possible ideas that could be relevant for the future deepening of our understanding of Nature, and do so regardless of whether the ideas may be experimentally tested in the near future or not, regardless of the very high energies that they may demand. In other words, you may do the kind of research that is more typical for the hep-th archive than the hep-ph archive.

As I have pointed out several times in the past, the new bunch of null results should really imply that the relative importance of the hep-th thinking and strategy – not caring whether the ideas may be tested in the near future – should have grown simply because those who have followed the other, "around the corner" philosophy of many hep-ph researchers, have (repeatedly) burned themselves and they should learn a lesson.

But aside from this lesson, it's clear that some people will keep on investigating profoundly theoretical ideas, perhaps those about Planck scale physics, while others will focus their minds on possible effects that may show up at the next collider. Both groups of questions are self-evidently scientific and no amount of fog by the anti-physics demagogues can ever change this elementary fact.

And it's clear that a big part of the truly theoretical ideas and advances, e.g. those in string theory, that were celebrated by the theorists in 2007 are still celebrated in 2017. You know, their being detached from experiments in the foreseeable future has been claimed to be a disadvantage. But now, after the "too ambitious, around the corner" models have been killed, what used to be called a disadvantage has been proven to be a clear advantage instead.

So the research in string theory, quantum gravity, and some top-down parts of quantum field theory is continuing just like it did before the LHC null results. Their impact on these fields has been minimal because they primarily use deep mathematics and long chains of argumentation applied to some experimental data that have been known for a rather long time, anyway.

Hossenfelder's demagogic claim that "everything has been killed that can be killed" isn't just some isolated wrong statement that has no consequences. She wants this piece of rubbish to have consequences, so the following paragraph of hers said:
The best candidate for a new trend that I saw in the past years is the “clockwork mechanism,” ...
She basically says "all of theoretical particle physics has been killed and now almost everyone has to study the clockwork mechanism". Needless to say, only complete idiots – a set that may include herself – would trust such a statement. Almost no important qualitative idea in particle physics has been "killed" – despite the $10 billion, the LHC is just a way too weak player for such tasks – and the clockwork mechanism remains a tiny portion of the research activity in particle physics. In the quote above, you may see the word "trend". Fake researchers such as Ms Hossenfelder are not trying to do actual science. They are trying to be trendy – and rely on those intruders in the broader community who think it is enough to be trendy. They are trying to find things that they consider "trends" and pretend to be up-to-date. But one can't really do serious physics (or any other science) in this way. Physics is working on a 10th floor of a skyscraper and you should better be sure that there are 9 floors beneath you if you want to do something sensible on this floor. Even though she accuses others, Hossenfelder is a great example of someone who wants to hover in the air above a cliff. Sorry but it won't work. If there's air beneath you, gravity will make sure that you fall to the asphalt and break your skull. The actual progress doesn't appear in some isolated new ideas that "throw away all the previous physics" and look for a trend of the recent years or months. The actual progress mostly takes place in the "minitrends" that are only visible in the subdisciplines of particle physics, to those who are good enough to know certain fundamental things that were established in the past, and not just the recent "trends". (OK, at this point, I can't avoid thinking about a recent question by Kashyap who also seems willing to listen about "trends" and he thinks that he may be ignorant about all the previous scientific results. Sorry, you can't.) But let me return to the first offensively demagogic sentence again: But there hasn’t been a big, new trend since the LHC falsified everything that was falsifiable. It also implicitly says that physicists have been lame and failing recently and they haven't even been able to invent some big fashion in recent times... Which recent times is she talking about? The timing is deliberately undefined in the sentence. But no big "trend" has occurred "since the moment when the LHC has falsified everything that could be falsified". I have already explained that it's pure rubbish to claim that the "LHC has falsified everything that could be falsified". But what timing could have been meant by that sentence? Well, when did the LHC falsify "all" the theories? For example, I paid my$100 bet to Adam Falkowski– which could have been a \$10,000 bounty for me if Nature had been more generous – some two or three months ago, in late March. That's when reasonable people could have concluded that the LHC had found no new physics after a big enough package of new searches (my bet was about 30/fb and it was the amount agreed upon a decade ago – we were not "extending" the deadline in any way).

It means that Hossenfelder is basically whining that the particle physicists haven't made a big trend-setting revolution between March 2017 and June 2017. What a catastrophe that they're not doing a trend-setting revolution every three months!

The type of garbage that is spread by the likes of Ms Hossenfelder – in explicit sentences but also in between the lines – is just stunning and it is very clear that she and others want to turn the readers into big haters of all theoretical physics, the kind of nasty uncultural folks who would throw all of the amazing theoretical physics that people have found into a trash can without a glimpse of a rational justification.

I am watching "Genius" on National Geographic, I liked the episodes so far, and there's a lot to say about them. One minor topic that I always found amazing is how identical the demagogy promoted by the likes of Hossenfelder and Woit is to the Nazi propaganda against Einstein and his physics, especially the dumb rants spread by Philipp Lenard, an experimenter heading the Aryan Physics movement who simply had no clue about theoretical physics and who licked the Führer's rectum in the most recent episode. He was full of the very same Woitian šit about Einstein's ideas not being testable and all this crap.

Many people have often told me that "it shouldn't be relevant" that e.g. Peter Woit's grandfather was one of the key politicians in his Baltic country when the murder of 40,000 Jews was organized in Riga in 1941. Woit can't be held responsible for the acts done by his grandfather in 1941, can he? No, he can't, but this hypothetical but non-existent acausal influence isn't the only possible source of problems resulting from Woit's ancestry.

You know, there existed actual influences that are real and didn't contradict causality. Woit's grandfather educated his kids in a certain way and those educated their kids in a certain way. Peter Woit is one of those that belong to the latter group and when it comes to theoretical physics, he thinks and talks exactly like a brain-dead Nazi. And this is a problem for me, whether you kindly "allow" me to realize this problem or not. History can't be changed but we may make sure that some of its worst mistakes aren't done again in the future. And to do so, it's damn too important to emphasize e.g. the Nazi roots of Woit's campaign against theoretical physics.