It turns out that at the LHCb, the hints of violation of lepton flavour universality just got stronger. For years now, measurements of the decays of a certain family of composite particles have shown slight deviations from the Standard Model. What is interesting is that all these deviations point into the same direction. None of these single measurements cross the magic 5sigma line but there is some debate whether one shouldn’t take the combined results into account which would be very close to the discovery level.
In any case, it is one of those measurements where the LHCb achieved more precision with more data, and the deviation remains. As with all potential cracks in the SM, a definitive discovery would both be groundbreaking because we would finally see errors in the most precise theory in history, and awkward because we wouldn’t know what is responsible for the error. Since this is high-precision physics that measures whether there are deviations in the percentages of predicted decays there is no detection of the actual forces or particles that are responsible for the deviations. The energies required are not accessible at least for a couple of decades.
Update: Résonaances has a blog post on this measurement, significantly increasing his posting speed! As huge fan of his blog, this is amazing news 😉
The Muon g-2 experiment is one of the last places where there is a reasonable hope of finding discrepancies with the Standard Model of Particle Physics. This Science Magazine article describes what this is all about and why it is relevant. Jester of Resonaances tweets that at this year’s Rencontres there is a talk “Most recent results from g-2 experiment”. This might just be an update, not necessarily the announcement of a discovery but who knows.
As far as I understand, even in the exciting case that we finally find something that the SM does not predict, this will not really change the current state of particle physics. Since this is a high-precision experiment, we will only know that something is wrong with the SM but not what or even at what energy scale. But even so, it would be the first crack in the SM and therefore a thing to celebrate.
David Tanzer on John Baez’ blog Azimuth advertised for a new blog The Signal Beat where you can find a series on language complexity.
The posts start by viewing a language as a set of all its sentences and then guide you through ideas such as how to decide whether a sentence belongs to that language and how complex that decision procedure is, ending on the P vs NP conjecture.
There’s an interview of David Adger in the current issue of Nautilus. It contains everything that the laws of physics dictate a linguistics interview should be about: Universal Grammar, merge, Arrival, Piraha, something something language is such a central part of human life/society blabla.
One (part of an) interview question that I celebrated was the following: Your ideas evoke probably the only controversy in the linguistics world that has spilled over to popular culture—the debate over “universal grammar.”
In general, David Adger is as informative and gentle as ever, using non-inflammatory rhetoric on the topic of UG (which is as always very welcome).
So, cool thing to have actual linguists in science magazines although the day is still to come where actual in-depth questions about theoretical linguistics are asked.
The Atacama Cosmology Telescope just released its measurements of the cosmic microwave background. The inferred expansion rate of the universe agrees with the ones of previous Planck missions.
This is interesting insofar as the question of the rate of the expansion is one of cosmology’s biggest mysteries right now. Measurements from the early universe and measurements of later times derived from i.a. supernova data do not agree. So this new measurement gives additional credibility to the old Planck data, making experimental error increasingly unlikely.
The Hubble tension as its called gets tenser and tenser.
Just discovered another (semi-active) linguistics blog: Buffalo linguist which is largely about phonetics, e.g. see here the most recent post on phonetic universals.
I’ll add the blog to my overview post.
News were making the rounds on Friday that the CERN council unanimously decided that in their research strategy they’re placing (most but not all) their bets on the Future Circular Collider (FCC), the 100km circumference proton-proton collider that would reach energies of about 100TeV. This is discussed in Nature and on Peter Woit’s blog.
A critical essay by Sabine Hossenfelder appeared in SciAm where she voiced her previous concerns that in contrast to the LHC there is no guarantee that physicists will find anything and that it is therefore hard to make a scientific case for such a huge amount of money.
Update: For anyone who speaks French or is able to use online translating tools, there is also an article in Le Monde about the topic by Adam Falkowski, author of Résonaances.
News came out just today that the XENON experiment, an underground lab in Italy looking for dark matter particles, saw a 3.5sigma excess in their data. Physicists right now are on a spectrum ranging from cautiously hyped to pessimistic due to trust issues from one too many disappearing anomalies.
If it is not due to impurities in their detector material which seems to be most people’s best cautious guess, and if the anomaly doesn’t vanish with more data, the best explanation would be axions or sofar unknown properties of neutrinos. However, both options also seem problematic since apparently that these particles with the properties necessary to explain the excess would carry away a lot of energy from stars (where they’re probably produced) than observations allow.
You can read about this, as always, in Quantamagazine and the experiment’s own webpage.
To honour the occasion, my favourite physics blog has awaken from its slumber: Résonaances aka Adam Falkowski is back with its first post in two years!
So, fingers crossed!
A new issue of Inference just appeared, this time again with articles on linguistics. The first one is about Misused Terms in Linguistics by Eveline Leivada where she undertakes the laudable task to define and explain controversial terms in linguistics; terms (such as, you guessed it, UG) that are controversial because, according to her, they have been used inconsistently and inaccurately. The best quote in the article by far is that ‘linguists would rather share each others’ toothbrush than each others’ terminology’. Something tells me that, still, all her definitions could lead to controversy.
The second is rather loosely related to theoretical linguistics, a text about people’s inner speech by David Lobina.
The news has made the rounds that the T2K experiment in Japan discovered evidence for an asymmetry in the behaviour of neutrinos and antineutrinos. The violation of this symmetry (CP-symmetry) seems to be almost as large as possible which is why the experiment was able to gather the data faster than initially thought.
More data is still needed for a definitive discovery which will still require some years to gather.
However, if this hint turns out to be true (and it seems most physicists expect that it will) then it will provide new directions for beyond-Standard-Model physics.
As usual, you can best read about it in Quanta (with an earlier discussion some years ago when this effect first turned up here). Nature and Interactions also have worthwhile articles, while CernCourier has a bit more technical coverage (with some explanation as to what such a result would hint at theoretically here).