When the discovery of the Higgs boson was announced, six years ago these days, an acquaintance said that the extraterrestrials will be like "okay, now we can start talking to you".
The Higgs is the uncontested star of 21st century physics - but it's not the biggest guy in the room: this is the top quark, the elementary particle weighing spectacularly more than any other. Progress was made lately in the measurement of these two animals' interaction. This took longer than for interactions of Higgs with other particles, as the high masses make the specific process more rare. But let me explain.
The centerpiece of research at the Large Hadron Collider is that accelerated protons carry a lot of energy which, when they collide, is released and quickly put into the form of other particles. This is the famous mass-energy equivalence (no, it's really famous; it's also known as "E=mc2"), but it doesn't happen haphazardly. Instead it is ruled by which kinds of particles can "speak" to which ones, which is ruled by the fundamental physical forces: the electromagnetism, the weak and the strong nuclear force. The fundamental forces govern the relations between particles - actually they
are the relations between particles. (In passing, the forces consist of actual particles themselves, exchanged between the other ones. But I digress.)
So, the laws related to the forces will dictate how often each possible particle interaction will pop up from the energy release in the collisions. Essentially, all research with colliders is based on calculating the characteristics of each interaction and how often it occurs, and then look for those. And Higgs and top, given that they are the heavy ones, have small chances of materializing, roughly speaking.
Last month though the two large LHC experiments, CMS and ATLAS, were able to update their measurement of the Higgs-top quark interaction. More accurately, they were able to elevate it to the stuff of legend, the holy grail of particle physics, the "5-sigma level"; which is a suave way of saying that the measurement is now so strong that the probability of it being random is less than one in three million.
...Only that the
calculated strength was slightly less than this number given how many collisions have been collected so far. An interesting small disagreement with the theory on an interesting interaction; yet one laden with much measurement uncertainty that might make it go away in the near future.
I must say that the experiments' announcements had a slightly exaggerated outlook on this difference, probably because several people are worried about the absence of any new, unknown physics at LHC. This worry is often expressed as disappointment at "only finding the Standard Model" so far, but imho we should be instead throwing random parties for years more, just to honour how great the Standard Model is. (And if you aren't already irrepairably sick of me praising this model of what the world is made of, you can read
here about how it came to be, from one of its founding figures, Sheldon Glashow.)
Hayabusa2 at Ryugu
A month without any cosmo VIP, but with a nice new small step for man. Or for a robot vehicle. Or for two impactors, four hoverers, three surface hoppers and said robot vehicle. Hayabusa2 is the first mission that will try both landing on an asteroid and returning samples to earth, and it has now arrived to its target after a 3-year journey involving some gravitational slingshot. (It is also the successor of a really pioneer mission, saved thanks to circuits secretly installed by its engineers.)
