The First Potential Detection of a Dark Matter Particle

0:00The mystery of Dark Matter and just what it actually is, has tentatively now had a major development that if it holds, might end the debate about what Dark Matter is, finally, and at least give us more information than we currently have. Tentatively is an important word here. Now before we get into this discovery, which I'll come out and say it, this is the first potential direct detection of a particle of Dark Matter, based on a single detection that does not have a sigma value of confidence that throws it over the top, but it is enough to be intriguing. In particle physics, a 5-sigma detection confidence is required to be on solid ground. Though in astrophysics, interestingly, that number is only 3. Here the detection was 2.6 sigma, so not a slam dunk by the cultural standards of particle physics, just halfway there. But it is a very intriguing and difficult detection to explain with anything other than

1:00Dark Matter. So as you probably know, Dark Matter is a mysterious substance of some sort that accounts for the vast majority of matter in the universe. It acts weird, it accumulates and interacts gravitationally, but it's puffy, and that it doesn't. So far as we know, really clump, like normal matter does. Rather it forms a halo. But there isn't a consensus there with in science because it may indeed clump, and there may be many different flavors of Dark Matter, and it's even been said that there may be Dark Matter asteroids, or even Dark Matter life. But although this is speculative and that we still had never detected Dark Matter at all other than through its gravity, this new finding comes from a detector called Lux Zeppelin or simply El Z. And what they do is search for Dark Matter in the form of what's called a Wimp, or a weekly interacting mass of particle. This is the leading hypothesis regarding the makeup of Dark Matter, and indeed, we know of such a particle already.

2:01There just aren't enough of them to account for all Dark Matter. That is, the neutrinos. So it's due to reason that maybe Dark Matter actually is a particle like a neutrino. Anyway, the experiment, using 220 days worth of data, recorded a single particle interaction that is very difficult to explain without some kind of Wimp being involved. Even with a low sigma, but not insignificant value, this represents the best so far regarding a Dark Matter detection. El Z is a huge collaboration. There are 250 scientists and engineers spread across 39 institutions involved, and is managed by the US Department of Energy, Lawrence Berkeley, National Lab. This is located about a mile underground in South Dakota and uses a whopping 10 tons of extremely pure liquid xenon. This is probably the largest single concentration of liquid xenon in the world, or at least among them. That is an absolutely enormous amount of xenon atoms, but that's what you need for such

3:04a rare detection. With xenon is hard to come by, we have to extract it from your satmosphere, and it is the rarest noble gas. It's amazing they did that. But anyway, more atoms, more chances for a detection to happen. Another key here is keeping the levels of trace radioactivity in the detector extraordinarily low, not an easy feat since background radiation is everywhere. But you can't eliminate that completely. Even with that much stable xenon, another components to reduce the effect, so the detector also had to have sophisticated software to be able to distinguish residual radioactivity from a signal from a WEMP, i.e. a potential dark matter particle. The bottom line, this is a very quiet detector. So the detection appeared right in the area where they expected dark matter to show up, and the background was proven to be low, so this appeared to be a legitimate detection. But since it's only one detection so far, that leaves uncertainties. Just random chance can produce a signal.

4:05It works that way in astrophysics too, and setty. But what this represents is the team at LZ to engage with the rest of the scientific immunity for viewpoints regarding the detection. That is the normal way to proceed in science. One interesting thing here is that this 220-day window, which ranged from March of 2023 to April of 2024, since this detector started taking data in 2021, there are still data sets to be searched that might yield further detections, because what produced this was a new analysis method that looked for a broader range of WEMP interactions. They also, with this new analysis method in mind, did a large amount of additional research into determining false positives in the new region they were looking at for interactions. This actually led to a very solid experiment, and that the researchers were extremely careful with background events. And this particular signal still stood out. But the interesting thing is, since this detector has only been running since 2021, and this

5:09is a new area to be searching the data sets for, that it showed up as early as 2023, means that dark matter interactions were in a different region than initially thought, but not out of the range from where it was expected. And that since it happened so early that it may not take too much longer for more detections to start piling up. As they do, the case will either become stronger that we have indeed found dark matter particles, and we know at least partly what this stuff is, but if we don't see it, or something ends up being off with the measurements, then we could have a bona fide mystery. If it wasn't dark matter, then what happened? It might be a while signaling particle physics, and remain forever unexplained. But again, it pays to keep in mind here that we don't actually know that dark matter is all one type of particle. There could be all kinds of flavors, and there may be free particles such as whims, but there could also be much more, an entire dark periodic table possibly. And at the world of dark matter is every bit as complicated as the world of normal matter.

6:13We simply don't know yet. But this experiment, if it continues to be successful, will start to place some constraints on how much of the dark matter bulk is made up of free-wimp particles. If that turns out to line up with the detections, then that would solve the mystery of dark matter or deepen it. If it doesn't line up, then the mystery of dark matter deepens. Because we would then have more than the neutrino to go on as far as non-interactive particles, but we also would know that there aren't enough whimps to account for the gravity that dark matter asserts. So the anomalous event, if it indeed was a detection of dark matter, means it would have a mass of at the very least 200 times that of the proton. That's pretty massive. Defining also suggests a type of interaction that wasn't actually expected. The simplest models didn't predict this. Explaining why it wasn't noticed until this study took a fresh look. That would be interesting if it holds, it would be a surprise. And that might lead to some interesting new facts regarding dark matter that were not

7:14anticipated, it would tell us something about it. Now what does 2.6 sigma actually mean in a particle physics detection? Well it actually is impressive. But physicists are a tough crowd. It means that there is only 0.5% chance that the detection was due to a known background event, like ambient radiation. But more is needed. There needs to be multiple detections. And the story will either become increasingly important and lead to dark matter or obia false alarm. The good news is that there is more ELSI data to search, and the detector will continue to at least 2028. It was designed for 1000 active data collection days and hasn't reached that yet. I'm not sure if they can prolong the experiment if it gets interesting, but it will at least give scientists an idea on where they need to look for dark matter. That really was kind of a shot in the dark. Where you look for something you have no idea what its characteristics are. Its fingerprints. You just know that if a Wimp model is right, you at least have a starting point and then

8:17you can revise from there. This work represents the revision. ELSI does represent the world's largest dark matter data set. Now why is this detector a mile underground? Basically shielding. The experiment in those that look like it looked for the emission of a photon, when there is a dark matter interaction and an after effect. Flashes of light come from the interaction. Well lots of things cause flashes of light, so you have to eliminate as much of that as you can in order to look for weakly interacting massive particles. As at least some of dark matter is suspected to be. Being a mile underground means you are shielded from high energy cosmic rays, the rock stops it. A water tank around the xenon and detectors provides further shielding from neutrons. And the whole thing is an exercise in making a really quiet detector. As low noise as you can get it. Even still outlier detections still happen. But in the case of this one, it survived scrutiny, at least so far.

9:18Now it's up to the particle physics community to think it over, when all this is published and basically try to shoot it down. If it survives, then more detections are needed of course. And when enough of them are found in confidence rises, then we can get into territory of handing out Nobel Prizes, for finally discovering at least one mechanism responsible for dark matter. But it's not guaranteed here, because it could just as easily be found to be a false detection. And the scientists were fooled by something they hadn't thought of. So there you have it. This one is a brand new anomaly that I suspect will need to get shot down or will lead to an important new insight into one of the universe's greatest mysteries. You know dark matter was sort of a prediction of very old one. It goes back to something Lord Kelvin talked about in 1884, and the term dark matter was on Re.K.A. in 1906. These were hints, hypothetical ones, that envisioned just such a thing. There were cues, a number of astronomers noted anomalies and observations until it came

10:22to a head with Vera Rubens work. And ultimately galaxies should fly apart with a matter that they have, but they don't. So there was missing mass. It's been a very puzzling mystery ever since. But maybe now we have started down the path of at least finding an answer. For the first in a series of answers. As often happens in science, that answer has a good chance of being more bizarre than anything we've ever heard about dark matter before. But exciting this is. If it holds, the adventure has just begun. Anyway, the Acariban colleagues' paper related to this is linked in the description below. Thanks for listening. A Futurst and Science fiction author John Michael Gaudier currently logic a complaint to the Big Bang. It made it to where most of the universe is invisible. And that, by definition, means it's hiding something. In regards to both dark matter and dark energy, it's the ultimate in hiding something, in fact. Very disturbing, but maybe not very long. And be sure to check out my books at your favorite online book retailer and subscribe to my

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