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Neutron = negative exterior + positive middle + negative core
September 20, 2007 8:23 PM   Subscribe

Particle accelerator experiments show that the neutron has a negatively charged exterior, a positively charged middle, and a negative core. Abstract from Physical Review Letters.
posted by russilwvong (44 comments total) 6 users marked this as a favorite

 
how many licks does it take to get to the centre of a Tootsie Roll Electron?
posted by heeeraldo at 8:42 PM on September 20, 2007


University of Washington news release. Previous measurements of neutron charge density.
posted by russilwvong at 8:42 PM on September 20, 2007


That was a typo—It's a "nougative" center.
posted by klangklangston at 8:49 PM on September 20, 2007 [8 favorites]


Okay so wait does that mean a neutron isn't neutral? It's just both positively and negatively charged? When I was a kid, subatomic particles was as small as it got. Now subatomic particles have subatomic particles. It's annoying.

In fact, I ain't never seen no neutron! If that lady on The View can pretend the world might be flat, I'm gonna stop believing in subatomic anythings. It's all a buncha hooey. String Theory too! It's all poppycock and you know it.

Heisenburg Uncertainty my butt! That's just a fancy pantsy scientific way to say scientists don't know anything.
posted by ZachsMind at 8:50 PM on September 20, 2007


It's an up quark and two down quarks. The up quark is positively charged and the down quarks are negatively charged. Could they be seeing the effects of the quarks with this experiment?
posted by Steven C. Den Beste at 8:50 PM on September 20, 2007


If only they talked about that in the first link, Steven C. Den Beste... oh wait, they do! :)
If the idea of a neutron having three differently-charged parts seems familiar, it may be because in quantum physics, neutrons are said to be made of three smaller particles called quarks: one "up" quark with a charge of +2/3, and two "down" quarks with a charge of -1/3. When joined together, the three quarks have a charge of zero.

Miller's findings would seem to suggest an actual physical location for these quarks within a neutron, but the truth, he said, is much more complicated.

"We're not taking about location as much as we are talking about density," he said. "What we are saying is the probability of finding a particular charge density is a function of distance. Quarks are constantly moving within a neutron, so this tells us the odds of finding more of them in one area over another."

The connection between quarks and charge location also breaks down when examining the proton, said Miller.

While a proton is made up of one down quark and two up quarks, the same accelerator tests found the proton was positively charged throughout, with the middle region possessing a stronger charge than the interior and exterior.
posted by Kattullus at 8:54 PM on September 20, 2007


It's an up quark and two down quarks. The up quark is positively charged and the down quarks are negatively charged. Could they be seeing the effects of the quarks with this experiment?
The article says that, although it's tempting to think that the results show that a down quark is wrapped by the up quark which in turn is wrapped by the other down quark, in reality, the quarks are constantly moving all over the place. The "negative, positive, negative" that they claim is actually the expected probability of the charge at that location at any given instant in time.

The proton is apparently positive throughout, despite the fact that one of its constituent quarks is a down (which is negatively charged).
posted by Flunkie at 8:54 PM on September 20, 2007


Jinx!
posted by Flunkie at 8:55 PM on September 20, 2007


We know nothing.

.
posted by Mr_Zero at 9:04 PM on September 20, 2007


This sounds strangely like a description of my wife.
posted by F Mackenzie at 9:30 PM on September 20, 2007


Venus...take it away.
posted by davebush at 9:44 PM on September 20, 2007


how many licks does it take to get to the centre of a Tootsie Roll Electron?

I came here planning to post almost exactly that phrase and it's the first comment; man am I unoriginal.

My version was, "sure, but how many licks does it take to get to the center?"

Mr Owl: "Well, that's a function of the Fine Structure Constant, but about 137."



...that ad would never fly.

posted by spiderwire at 9:51 PM on September 20, 2007 [3 favorites]


So 'neutron' is obviously a confusing misnomer. Let me be the first to suggest 'wigglytron' as the new name, for no reason other than I think it's cute.
posted by pompomtom at 9:59 PM on September 20, 2007


Any product advertised with a fine-structure constant joke is a product I would buy.

There is, unfortunately, a rather small number of people who might say this along with me.
posted by Arturus at 10:31 PM on September 20, 2007 [1 favorite]


I've been reading a lot of primary literature lately, so I thought I could tackle the abstract. But it turns out quantum physics abstracts read a bit differently than ecology abstracts.

"...the square of the transverse charge radius is positive, in contrast with many expectations..."

Surely the square of any quantity measured in there would be positive, unless there's weirder shit going on than I realize. Why is it in contrast with many expectations?
posted by lostburner at 10:42 PM on September 20, 2007


lostburner:

From reading the abstract it seems to me that it was expected that the square of the transverse chage radius would be zero. Nonzero quantities would indicate nonuniform spatial distributions of charge (such as they found).

Of course, I haven't read the whole paper...
posted by claudius at 10:52 PM on September 20, 2007


lostburner: imaginary numbers.. I've just touched on them briefly but the gist of it is they're numbers whose square is a negative value.

I'm convinced that this is one of the things that makes people give up on math altogether.
posted by Grimgrin at 10:57 PM on September 20, 2007


he neutron has a negatively charged exterior, a positively charged middle, and a negative core.

Son of a bitch!
posted by From Bklyn at 12:23 AM on September 21, 2007 [1 favorite]


and this was beautiful as only cheesy, message driven moments on late seventies TV can be beautiful. I laughed, I cried. I think it changed my life...
posted by From Bklyn at 12:37 AM on September 21, 2007


I wish I had access to the article, but to me (recreational physicist) this really doesn't seem to be that big of a deal.
posted by Alex404 at 12:42 AM on September 21, 2007


Oh, see, now it works. Reverse the flux capacitor my fat ass!
posted by loquacious at 1:08 AM on September 21, 2007


ARGH NO WONDER MY MR. FUSION KIT NEVER WORKED!

BRB, gonna try something real quick.
posted by loquacious at 1:08 AM on September 21, 2007 [2 favorites]


(At the risk of totally derailing into WKRP, it now occurs to me that Senator Chris Dodd (D-CT) looks a lot like Herb might aged 25 years. And Johnny Fever is still awesome.)
posted by blacklite at 2:03 AM on September 21, 2007


loquacious, you're giving me flashbacks to this thread.
posted by Arturus at 3:21 AM on September 21, 2007


This was the missing piece in my Antihadron Inverting Annihilator. Now you're all going to pay.

-Prof. Doomsday
posted by Eideteker at 4:31 AM on September 21, 2007


The other Daleks thought I was crazy when I told them black holes were really gravastars.
Now they can bite my shiny metal ass.
posted by Smart Dalek at 4:46 AM on September 21, 2007 [1 favorite]


"Venus...take it away."

Holy crap, jonmc was right. I'm the Venus Flytrap to his Dr. Johnny Fever. We should take this show on the road.
posted by Eideteker at 4:49 AM on September 21, 2007


I'm convinced that this is one of the things that makes people give up on math altogether.

If I can't do it with View>Scientific enabled, I can't do it.

My gut feeling has always been that as we learn to see smaller better, we will coninuously see smaller things, and that seems to be bearing out, since the 60's, anyway.
posted by Devils Rancher at 4:52 AM on September 21, 2007


As with most physics papers, there's a preprint of this at the arxiv that you can look at for free.
posted by Schismatic at 5:32 AM on September 21, 2007


pompomtom: great name, but I think all the particles are wigglytrons.
posted by MtDewd at 5:42 AM on September 21, 2007


But is this really any weirder than electron probability density clouds (that is, electrons don't orbit the nucleus like planets around the sun but instead have a probability of being somewhere in a certain sometimes strangely-shaped zone somewhere near the nucleus)? Graphic, also newer graphic top right in the wikipedia article. When you get down to that subatomic scale, the whole notion of what we would recognize as "things" having specific "locations" gets problematic.
posted by aught at 5:43 AM on September 21, 2007


What do these findings imply for Jimmy Neutron and his evil twin, Jimmy Negatron?
posted by lukemeister at 7:04 AM on September 21, 2007


So 'neutron' is obviously a confusing misnomer. Let me be the first to suggest 'wigglytron' as the new name, for no reason other than I think it's cute.

How about just 'tron?
posted by kosem at 7:50 AM on September 21, 2007


My version was, "sure, but how many licks does it take to get to the center?"

Mr. Owl: Let's find out! One... a-two-HOOOO*mushroom cloud*
posted by eddydamascene at 8:15 AM on September 21, 2007 [3 favorites]


interesting article. While neutrons are still of course neutral, it is very interesting to see that the "distribution" of quarks that make up the neutron do not appear to arrange themselves in a manner that averages out to a constant charge distribution of zero, while protons seem to have a more regular "distribution". Perhaps this leads to some insights as to why the proton seems to have an infinite life time.
posted by ozomatli at 8:26 AM on September 21, 2007


Hermaphrotron?
posted by Ynoxas at 8:48 AM on September 21, 2007


It'd be interesting to see results for more hadrons to be able to make generalizations. It might be some quantum chromodynamics effect, for example.
posted by vacapinta at 11:04 AM on September 21, 2007


eddydamascene, you just cracked my ass up. Bravo!
posted by zoogleplex at 12:06 PM on September 21, 2007


I learned back in first year physics that electric fields don't exist inside hollow conductors.

What gives, science?
posted by Bletch at 12:12 PM on September 21, 2007


Heeeraldo, Devils Rancher: I'm pretty sure the electron (and all leptons) are still thought to be fundamental particles, i.e. they're pointlike and indivisible.
posted by hattifattener at 12:12 PM on September 21, 2007


I learned back in first year physics that electric fields don't exist inside hollow conductors.

What gives, science?
posted by Bletch at 2:12 PM on September 21 [+] [!]


Bletch,

Partons (neutron and protons) are not hollow shells of electric charge. They have a charge density.
posted by ozomatli at 2:20 PM on September 21, 2007


"So this neutron walks into a bar and orders a beer. He asks the bartender "How much?", to which the bartender replies: For you: no charge...."
posted by ZenMasterThis at 5:32 PM on September 21, 2007 [1 favorite]


Two hydrogen atoms are walking down the street. One turns to the other and says "I've lost an electron!"

The other says "Are you sure?"

"I'm positive!"
posted by darkstar at 11:00 PM on September 21, 2007


*wiggles in and out of higher dimensions*
posted by trondant at 4:47 AM on September 22, 2007


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