Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Biggest dark matter detector spots a single weird particle

science.org

Post reply on HN
Print view View original

41–50 of 152 posts

Re: Biggest dark matter detector spots a single weird particle

#41

Post by gus_massa »

irishcoffee wrote: post #22
matthewdgreen wrote: post #21

Earlier quoted context omitted.

This sort of thing is really useful for helping people to understand what the purpose of scientific publication is. It's not about presenting finished products to society, it's more like a Discord where you communicate new findings with other authors. Often the reason for a communication is because you found something weird, and you want other people to know about it so they can help you confirm or rule it out as bad…

You have accurately described a email mailing list. Where in the value-add here?

No so wrong. The oldest journals started as smailing list :)

https://www.scientificamerican.com/blog/information-culture/...

Re: Biggest dark matter detector spots a single weird particle

#42

Post by isomorphic »

advisedwang wrote: post #31

> Such behavior could require dark matter to be more complicated than just a single new type of particle. For example, the dark matter particle might have some internal structure, like an ordinary atom, so it would only interact if hit hard enough to excite it to a higher energy internal state I get a little shiver imagining that the dark matter might be something like ordinary atoms. Imagine that other 85% of the un…

I've heard this referred to as a "dark sector", or "hidden sector":

https://en.wikipedia.org/wiki/Hidden_sector

The scary thought is that, were it true that there is voluminous richly-interacting dark matter, we would be the actual dark sector.

Re: Biggest dark matter detector spots a single weird particle

#43

Post by matthewdgreen »

irishcoffee wrote: post #22
matthewdgreen wrote: post #21

Earlier quoted context omitted.

This sort of thing is really useful for helping people to understand what the purpose of scientific publication is. It's not about presenting finished products to society, it's more like a Discord where you communicate new findings with other authors. Often the reason for a communication is because you found something weird, and you want other people to know about it so they can help you confirm or rule it out as bad…

You have accurately described a email mailing list. Where in the value-add here?

If I had the email address of every researcher in my field, I would never send a mass email to them describing my latest goofy idea. I would, however, send my latest goofy idea to a conference with those same reviewers (if I felt it was technically appropriate and correct.)

Re: Biggest dark matter detector spots a single weird particle

#44

Post by cogman10 »

gus_massa wrote: post #16
SaberTail wrote: post #9

Earlier quoted context omitted.

To start with, they do a lot of work to eliminate radioactive backgrounds in the materials they're using, and they put the detector deep underground to shield from cosmic rays. Additionally, when a particle interacts with the nucleus, the ratio of how much energy ends up as scintillation light versus ionization is different than when a particle interacts with an electron, which is most of the background processes. Th…

I agree. Moreover, I'm not sure if it's the same team, but in a similar experiment while removing all the other effects, they discovered that Xenon 124 is radioactive, but the half life is super long and no one had seen it before. https://xenonexperiment.org/observing-the-rarest-decay-proce...

Makes me wonder if all atoms with 2+ nucleus elements (protons and neutrons) are radioactive but the halflife is so far out as to make something we'll never detect.

Re: Biggest dark matter detector spots a single weird particle

#45

Post by Nevermark »

imglorp wrote: post #29
SaberTail wrote: post #15

Earlier quoted context omitted.

In one sense anything that passed all their background rejection is a WIMP. To interact with a nucleus through so much matter, it's not interacting electromagnetically. The main candidate for a strong force interaction would be a neutron, and they did a lot of work to model that and eliminate it as a background. So definitionally it would be a WIMP. They were pretty model agnostic in what they were looking for. They…

If neutrons are on the list, how are they ruled out from a random decay event emitting particles, from some mineral in the surrounding rock?

The experiment is set up to make any already understood interactions some combination of easy to identify or extremely improbable.

Re: Biggest dark matter detector spots a single weird particle

#46

Post by gizmo686 »

hyperhello wrote: post #40
advisedwang wrote: post #31

> Such behavior could require dark matter to be more complicated than just a single new type of particle. For example, the dark matter particle might have some internal structure, like an ordinary atom, so it would only interact if hit hard enough to excite it to a higher energy internal state I get a little shiver imagining that the dark matter might be something like ordinary atoms. Imagine that other 85% of the un…

It's possible that there could be an entirely different charge mechanism that works exactly like ours but they don't interact at all; but the whole premise of dark matter is that it doesn't seem to have any self-interaction outside of gravity.

The premise of dark matter is that it is something with gravity that does not otherwise interact with any of our detectors (e.g. "normal" matter); or that any such interactions are weak enough that it is plausible we have not noticed.

By itself, that does not exclude the possibility of dark matter having other interactions which do not interfere with our detectors.

Re: Biggest dark matter detector spots a single weird particle

#47

Post by marcosdumay »

cogman10 wrote: post #44
gus_massa wrote: post #16

Earlier quoted context omitted.

I agree. Moreover, I'm not sure if it's the same team, but in a similar experiment while removing all the other effects, they discovered that Xenon 124 is radioactive, but the half life is super long and no one had seen it before. https://xenonexperiment.org/observing-the-rarest-decay-proce...

Makes me wonder if all atoms with 2+ nucleus elements (protons and neutrons) are radioactive but the halflife is so far out as to make something we'll never detect.

There's just no way deuterium is radioactive, unless hydrogen is radioactive too.

Re: Biggest dark matter detector spots a single weird particle

#48

Post by cwmma »

cogman10 wrote: post #44
gus_massa wrote: post #16

Earlier quoted context omitted.

I agree. Moreover, I'm not sure if it's the same team, but in a similar experiment while removing all the other effects, they discovered that Xenon 124 is radioactive, but the half life is super long and no one had seen it before. https://xenonexperiment.org/observing-the-rarest-decay-proce...

Makes me wonder if all atoms with 2+ nucleus elements (protons and neutrons) are radioactive but the halflife is so far out as to make something we'll never detect.

Probably not, they have a pretty good handle on why atoms decay, to the point they can predict some to be radioactive before it's actually observed to be (like Bismuth-209).

Also even if something is REALLY REALLY long lasting, you can still check for the halflife by observing enough of it, they've been able to rule out proton halflives under 10^34 years (the universe is on the order of 10^10 years old) but by observing enough protons (like say 50,000 tons of water) you would expect at least some to decay.

Re: Biggest dark matter detector spots a single weird particle

#49

Post by gus_massa »

marcosdumay wrote: post #47
cogman10 wrote: post #44

Earlier quoted context omitted.

Makes me wonder if all atoms with 2+ nucleus elements (protons and neutrons) are radioactive but the halflife is so far out as to make something we'll never detect.

There's just no way deuterium is radioactive, unless hydrogen is radioactive too.

Some theories predict that protons decay, but the half life is like 1E31 or 1E35 years (compare to the Xe124 that has a half life of only 1E24 years). All experiments so far to measure the proton decay have failed, anyway. https://en.wikipedia.org/wiki/Proton_decay

I don't remember anything specific about deuterium, and the method that Xe124 uses is not available, and I can't imagine a razonable alternative method, so my guess is that deuterium is as stable as protons.

Re: Biggest dark matter detector spots a single weird particle

#50

Post by dd8601fn »

WarmWash wrote: post #37
smueller1234 wrote: post #10

Earlier quoted context omitted.

Or this[2] 2007 Science paper on ultra high energy cosmic ray source candidates ("anisotropy") that we had to retract because significance started dropping almost the day the paper was approved. It was a fascinating experience as a junior member to follow the collaboration internal conversation and investigation on this, because a lot of extremely principled scientists were clearly deeply worried about losing their h…

Reminds me of the FTL neutrinos too, where the scientist where pretty much "hey, something is wrong, can you help us figure it out?" and the general public were the ones screaming "OMG! Physics is dead!" Then when it comes out as measurement error, the public is all "Damn these scientists are all hype machine clowns..."

I’m fine with that. Put it at the feet of pop science blogging.

I’m less fine with the time and resources spent on mouse models. They already know you’d get the same utility from a magic 8 ball, but they do it anyway.

Post reply on HN