Fermilab to announce new physics

April 6, 2011 1:53 PM

The CDF collaboration at Fermilab is set to announce evidence for non-Standard Model physics today. The experiment at the Tevatron particle collider has released a paper on the Arxiv stating it has found evidence for a potential new particle that isn't the Higgs boson. A live stream announcing the results will begin at 4pm Central time (21:00 GMT).

Excess events (at 3.2 standard deviations) were found in quark jet events corresponding to a particle mass around 144 GeV. Dedicated Higgs searches in the same mass region turned up negative, implying that this could be non-Standard Model physics. The paper, cautiously, makes no guesses about what kind of physics is being observed.

CDF's sister experiment at the Tevatron, D0, has yet to weigh in. Whether D0 sees the same signature will go a long way in confirming whether a signal is actually present.

posted by auto-correct (50 comments total)

The livestream is live now.
posted by auto-correct at 2:01 PM on April 6, 2011

I have absolutely nothing insightful to say about this topic except that I always try to sit on the right side of the plane when I fly west out of Midway so I can see the Tevatron.
posted by theodolite at 2:02 PM on April 6, 2011 [1 favorite]

... and it went down.
posted by Foci for Analysis at 2:02 PM on April 6, 2011

Aaaaand, I'm getting an error 500.
posted by PROD_TPSL at 2:03 PM on April 6, 2011

The livestream is a deadstream.
posted by Threeway Handshake at 2:03 PM on April 6, 2011

Still streaming here.
posted by cmfletcher at 2:04 PM on April 6, 2011

"Is That A New Massive Particle? Is That Some Kind Of Higgs?" from Fermilab physicist Tommaso Dorigo
posted by mrgrimm at 2:04 PM on April 6, 2011 [1 favorite]

tldr: "I believe this is nothing but the umpteenth would-be new physics signal, destined to be buried by the analysis of further data, by the crafting of more precise simulations, or by the better understanding of Standard Model sources."
posted by mrgrimm at 2:05 PM on April 6, 2011

Working link
posted by Foci for Analysis at 2:05 PM on April 6, 2011

Goddammit. I think it's working if you started it early enough, but they're not letting new people in. The talk will be available after it finishes, I'll make sure to post a link when it's up.
posted by auto-correct at 2:06 PM on April 6, 2011

FermiLab is probably gettings Ars'ed, Slashdotted, Digg'ed, and Mefi'ed.... ALL AT THE SAME TIME.
posted by PROD_TPSL at 2:06 PM on April 6, 2011

"Is that a Higgs Boson in your quark jet stream or are you just happy to see non-standard physics?"
posted by mr_crash_davis at 2:07 PM on April 6, 2011 [7 favorites]

nothing a couple of epicycles can't fix.
posted by ennui.bz at 2:08 PM on April 6, 2011 [6 favorites]

tldr: "I believe this is nothing but the umpteenth would-be new physics signal, destined to be buried by the analysis of further data, by the crafting of more precise simulations, or by the better understanding of Standard Model sources."

I won't argue with that at all, and there's certainly recent evidence of Tevatron experiments publishing questionable results.

But di-jet events are one of the most well studied processes in high energy physics, and the Tevatron experiments have had 20 years to get to know their detectors. It's good to be skeptical, but this shouldn't be brushed off casually.
posted by auto-correct at 2:10 PM on April 6, 2011 [1 favorite]

The talk will be available after it finishes, I'll make sure to post a link when it's up.
posted by auto-correct at 2:06 PM on April 6 [+] [!]

Damn you!
posted by PapaLobo at 2:18 PM on April 6, 2011 [1 favorite]

and how much that particle must weigh

GAAH... I can't even read this ars technica article because he's using 'weigh' everywhere :(
posted by empath at 2:19 PM on April 6, 2011

Foci for Analysis posted a link that works for me.
posted by PROD_TPSL at 2:19 PM on April 6, 2011

TMBG linked to this on their facebook feed, the caption was "Particle wins"
posted by hellojed at 2:20 PM on April 6, 2011 [10 favorites]

I can't even read this ars technica article because he's using 'weigh' everywhere

If only a few Kurds were involved, we could all sit down and eat!
posted by hippybear at 2:23 PM on April 6, 2011 [3 favorites]

The paper is interesting. They're pretty clear about only being at 3.2 standard deviations. Particle physicists usually require five sigma before they say "now it is serious." Even that isn't proof, but it does get you past the "interesting anomaly" stage.

The reason they are mentioning the Higgs boson is that estimates for its mass (should it be found) are in the 115 GeV to 185 GeV range, and here they have something estimated in the 120 GeV to 160 GeV range. So the first thing everyone is asking is Higgs? but apparently it ain't so. This particle is more than a hundred times as heavy as a proton.

I wonder if they are going to make noises about supersymmetry.
posted by adipocere at 2:25 PM on April 6, 2011 [1 favorite]

Does this have any relevance to that "exceptionally simple theory of everything" guy's ideas? (Previously) I seem to recall from that thread that his theory did make some predictions that were supposed to be measurable once the LHC came online. (I'm a complete layperson where physics is concerned, and I don't even know if his theory ever got taken seriously by the physics establishment.)
posted by whir at 2:40 PM on April 6, 2011

The presenter was very careful not to say anything prematurely. I didn't even hear her say the words "Higgs" or "Supersymmetry" as speculation. They're dealing with this very responsibly.
posted by auto-correct at 2:40 PM on April 6, 2011

There is no God (particle).
posted by dances_with_sneetches at 2:42 PM on April 6, 2011

I understand none of this and therefore I am afraid.

Burn the science witches and their sinful machines! Cleanse the Earth with fire!
posted by Avenger at 2:47 PM on April 6, 2011 [5 favorites]

Does this have any relevance to that "exceptionally simple theory of everything" guy's ideas?

No.

I'm a complete layperson where physics is concerned, and I don't even know if his theory ever got taken seriously by the physics establishment.

The reaction to the physics community was basically that he was not a crank or a crackpot, but that his theory had some serious mistakes that sunk it.

----

I didn't even hear her say the words "Higgs" or "Supersymmetry" as speculation.

That's because it's not a Higgs boson. (Standard model) Higgs bosons decay into bottom quarks and there aren't enough bottom quarks here.

From reading various theoretical physicists blogs now, it seems the most likely explanation is a mistake. The second most likely explanation is a Z' boson, which would be a new force (not gravity, electromagnetism, strong, or weak). As to what a fifth force might do, I don't know, I'd have to read some of the Z' papers, first. Motl (who is generally skeptical about the paper) says that a fifth force might have to do with symmetry breaking)
posted by empath at 2:47 PM on April 6, 2011 [3 favorites]

The livestream is a deadstream.
posted by Threeway Handshake at 2:03 PM on April 6

Still streaming here.
posted by cmfletcher at 2:04 PM on April 6

Schrödinger's livestream.
posted by weapons-grade pandemonium at 2:48 PM on April 6, 2011 [23 favorites]

a Z' boson ? ZOMBIES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
posted by Pendragon at 2:50 PM on April 6, 2011

As an ecologist, can I just say I'm fascinated by the things you physicists do with your bosons and your quarks. Also, I wish we got to hold press conferences like this.
posted by Jimbob at 2:52 PM on April 6, 2011 [1 favorite]

Boson always scans a little bit like "bison" and a little bit like "bosom" when I read it and, thus, it is counted among my favorite words.
posted by Joey Michaels at 3:07 PM on April 6, 2011 [3 favorites]

But di-jet events are one of the most well studied processes in high energy physics, and the Tevatron experiments have had 20 years to get to know their detectors. It's good to be skeptical, but this shouldn't be brushed off casually.

Even if the end result is just better modeling of known interactions for future experiments that explains the anomaly without a new particle, this is still good science.
posted by empath at 3:16 PM on April 6, 2011 [1 favorite]

Here be dragons?
posted by Kevin Street at 3:21 PM on April 6, 2011

From reading various theoretical physicists blogs now, it seems the most likely explanation is a mistake.

The only mistake that's likely to be happening -- and I find it hard, but possible to believe it would happen, is a mischaracterization of the W+ background. They did try various characterizations of the background, the signal is still there.

3.2 Standard deviations is pretty significant. In HEP, 3σ is "Hmm, we'd better look at it really carefully," usually you won't call it found until you have 5σ or a bunch of other detectors are showing similar signals to yours.

The big tell -- there are three other detectors that can see this signal -- D0 @ Fermi, and ATLAS and CMS at LHC. I'm sure someone's digging through the data now -- and this paper has very carefully written. It says 'There's a signal here, we cannot explain it. Anybody else seeing it?'
posted by eriko at 3:24 PM on April 6, 2011 [5 favorites]

Boson always scans a little bit like "bison" and a little bit like "bosom" when I read it and, thus, it is counted among my favorite words.

What are your thoughts on "hadron"?
posted by mr_roboto at 3:31 PM on April 6, 2011 [22 favorites]

It's the luminiferous aether back again, I tell you. Dark matter? Seas of virtual particles? Broken symmetry? Come ON. Albert said we needed it. Pauly D said we needed it. It never went away...
posted by Devonian at 3:32 PM on April 6, 2011 [1 favorite]

This could be the most significant discovery in physics since the last time we made the most significant discovery in physics.
posted by warbaby at 3:34 PM on April 6, 2011

so is this, or this not evidence that God throws dice?

And if not dice, what about croquet?
posted by philip-random at 3:37 PM on April 6, 2011 [1 favorite]

Well, if you're a statistician you already know that God plays at dice. We're also looking at lots of things in a general sense and not one particle though...

Very, very carefully worded paper. Is there an igNobel category for most pre-emptively deflated discovery?
posted by Slackermagee at 4:15 PM on April 6, 2011

This must be the Devil particle. Makes sense that we'd find it first.
posted by Crabby Appleton at 4:33 PM on April 6, 2011 [1 favorite]

What are your thoughts on "hadron"?

Nothing really, just happy to see you.
posted by mrgoat at 5:23 PM on April 6, 2011 [4 favorites]

Boson always scans a little bit like "bison" and a little bit like "bosom" when I read it and, thus, it is counted among my favorite words.

I have good news and bad news...

Broadening our experimental cutoffs a bit ... bison meat is one of the healthiest, low fat red meats ...
posted by sebastienbailard at 5:55 PM on April 6, 2011 [1 favorite]

My brother has been an electrical engineer at Fermilab for almost thirty years. I used to ask him about his work, but I stopped when I realized that I would never understand what the hell he was talking about. He designs detector circuitry.

There's a strong possibility that he, and a lot of other deeply experienced and passionately dedicated people who actually make the magic of high energy physics happen, will be looking for a new job when Congress finishes swinging the ax.

My request of those of you who care about science is that you write or call your Congressperson and let your feelings be known.

Basic science research is important and it doesn't pay for itself. At least, not right away.
posted by double block and bleed at 6:19 PM on April 6, 2011 [10 favorites]

I used to work for CDF when I was an undergraduate, ironically enough, I was looking for new physics too. But I was looking at high energy electron and muon events.

I will say that the collaboration has been around for a long time and there are people there that really know the ins and outs of the physics and the detector. It is a big collaboration (like ~1000 people) which means, on the one hand, that things can be tangled and bureaucratic and confusing to newcomers but, on the other hand, no one is working alone. If someone publishes a paper you can believe that dozens of other scientists have met about the work, commented on it, read the paper, studied the data, etc.
posted by mai at 6:52 PM on April 6, 2011

Sorry guys, this one is on me. There is a Sonic Drive Thru near there, I over ate, yadda, yadda, yadda, those aren't the kinds of particles they think they are.
posted by gjc at 6:56 PM on April 6, 2011

I believe this classic article is by the same authors.
posted by neuron at 7:04 PM on April 6, 2011 [1 favorite]

It's the ukulelotron. We can only see it now that that planet has accrued a critical mass of ukuleles.
posted by obiwanwasabi at 7:47 PM on April 6, 2011

E8 Theory predicts new particles... is this one of them?
posted by j03 at 8:00 PM on April 6, 2011

Boson always scans a little bit like "bison" and a little bit like "bosom" when I read it and, thus, it is counted among my favorite words.

That's because they are emitted by the bison at Fermilab.
posted by goethean at 8:16 PM on April 6, 2011 [1 favorite]

So is the consensus that this is a "hey, maybe something, we need to wait $interval to get more/better data" thing? What will be the interval before we know if this is actually a big huge deal?
posted by LobsterMitten at 12:08 AM on April 7, 2011

Empath: That's because it's not a Higgs boson. (Standard model) Higgs bosons decay into bottom quarks and there aren't enough bottom quarks here.

Higgses can decay hadronically in different ways; H->b + b-bar is the dominant process for a low mass Higgs, but H->WW->jets + lepton + neutrino is also a significant decay and could conceivably contribute to the signal in the paper. (Here's a plot of the Higgs branching ratios; at the ~140 GeV range WW is already overtaking bb). The authors say that associated searches rule out a Higgs (I assume they looked for H->WW->2leptons + 2neutrinos and H->WW->4jets and didn't see anything), and I believe them, but I'll bet the first thing on everyone's mind the first time they saw that plot was that it's a Higgs signal.

All I meant by my comment is just that that the speaker was being very careful not to speculate on any physical cause for the bump, which was definitely the right route to take. The talk around my (non-Tevatron related) office was full of all kinds of baseless speculation, which was a lot more fun, but a lot less cautious.

Also, don't believe theorists when they say "it's probably just a fluctuation". They may be right, but they're just saying that because they're embarrassed they didn't predict it first :P
posted by auto-correct at 1:12 AM on April 7, 2011 [2 favorites]

So is the consensus that this is a "hey, maybe something, we need to wait $interval to get more/better data" thing? What will be the interval before we know if this is actually a big huge deal?

The two experiments at the Tevatron, CDF and D0, have historically published together whenever the find something interesting (like the top quark discovery, and Higgs exclusion limits). The fact that CDF went alone on this one is kind of surprising, and possibly a red flag.

D0 will probably publish something within weeks or months whether they see something or not. If they do see the same effect, expect people to be a lot less skeptical (but not convinced, since they rely on the same simulation programs and could be making the same mistake). If they don't see it, expect everyone to pretend this never happened.

What will it take to be confident that this is something real? In my opinion, it would take ATLAS/CMS also seeing it, plus a convincing theoretical explanation for what it is. So, uh, it may take a while.
posted by auto-correct at 1:22 AM on April 7, 2011 [1 favorite]