You need to look at the source. Most Forbes content is bad, but this is Ethan Siegel's blog, which is usually pretty good.
The CERN article is also good, and the two don't actually contradict each other -- nobody is rebutting anybody else. An anomaly which has only a 5% chance of holding up still is extremely exciting. Probably not worth all the media attention it randomly got, but definitely worth more investigation by physicists.
I case anyone wasn’t already aware - Forbes.com allows just about anyone to publish on their platform. Their editorial standards are FAR more lax than the print publication that shares its name.
> Examining the number of electron–positron pairs at different angles of separation, the researchers found an unexpected surplus of pairs at a separation angle of about 140º.
I keep reading about this "angle" in regards to beryllium-8 and X17. Can someone ELI5 for a non-physics person what it means for particles to come off at a certain angle?
Imagine a slow moving blob heading towards a target on a wall, a small charge causes it to explode at some point along its path to the wall. The larger the charge the wider the splatter. In this case, the mass is the analogy to that detonation charge. If that blob was photons alone (which are the standard model assumption) you'd expect a smooth decreasing amount of splatter as you go away from the center of the target, what they seem to be seeing is an unexpected increase around 115 - 140 degrees.
Its pretty much what it sounds like, when there are particle collisions or decays, the particles come off at certain characteristic angles relative to the beam that are signatures of certain types decay and energies.
In this video, look for the forks that happen in the vapor trails being generated, that is a particle collision, and the corresponding sort of angle being talked about here.
This technique works because the air is essentially super saturated with moisture, so even very slight atomic level disturbances will cause the water to condense to form mini "clouds" (hence the term cloud chamber).
Its difficult to find videos about, but antimatter pair production will cause patterns that look like this for instance
Thanks very helpful, the angles being signatures to help determine what forced/objects are involved makes a lot more sense to me now. That's always been something I've struggled with in biology/chemistry and physics is the higher level abstractions used to infer smaller phenomenons that are not as easily observable.
I'm too used to compsci where it's more explicit and every "but why?" doesn't lead you down a Wikipedia rabbit hole.
It's a literal angle, like you learned in geometry class. After the decay, two particles fly off in different directions. They mean the angle between those directions.
Apologies I meant what the significance of the particles bouncing off at certain angles, particularly down to the degree as others have mentioned the different ranges reported. My short google search earlier didn't help me much. Others have provided some links I will dig into.
You can use the angle (in conjunction with trig applied to various conservation principles such as conservation of momentum) in an attempt to derive quantities like mass.
I might be mistaken but from my college chemistry I believe this is referring to VSEPR theory. Where electron pairs around a nucleus will push against each other to maximize the distance between other pairs in spherical space. So two electron pairs would be separated by 180° (line) and 3 by 120° (3 lines on same plane), 4 by 120° (tetrahedron) and so on.
So if it's 140° then something else is pushing against them as it should never be 140°.
Someone more knowledgeable correct me if I'm mistaken.
I find it interesting that there is no mention of NA64's sensitivity to the particle. Is it possible to say from the Atomki institute experiments what is the rate of production expected at NA64? Somehow LHCb will be able to refute or confirm but only by 2023.
If you understand Spanish, here is a video of a complete and easy to grasp introduction to what this new force is, what it means and how it was discovered:
The "plot thickening" is that this is CERN's take on the matter, which has been following it for years -- so to them, the same arxiv article constitutes "new information" that came as just plain news to everybody else.
Other than that, there's nothing here you haven't seen before aside from a few interesting quotes from CERN people.
https://news.ycombinator.com/item?id=21616084
https://news.ycombinator.com/item?id=21616381