what? No mention of the Higgs Boson yet?

[jesternl]

http://public.web.cern.ch/public/

Press conference is about to start..

[JDTAY]

Is it over yet? Did they find the boson? Can we teleport now? Keep us updated, jesty.
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Prohibit nothing. Disclose everything.

[Jack_Ian]

I watched about 10 minutes of it, but it was pretty boring. Just talk about statistics and margin for error. Perhaps I picked the wrong 10 minutes to tune in.

[Scurra]

Best joke I have heard on this: My trumpet teacher at school was Mrs Higgs. It's a good job she didn't teach the Bassoon or she'd be in all sorts of hell right now.
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_{still Quiz Olympiad champion. Must get a life.
New definitions: COFFEE - someone who is coughed upon}

[wordcross]

From the followups I've read, it seems they didn't find the higgs boson, they've pretty much just narrowed down the range of where to look for it by a lot.
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Has anyone really been far even as decided to use even go want to do look more like?

[Jack_Ian]

Why is it always in the last place you look? (even if it's in the first place you looked)

[Lepton*]

Given the exponential cost involved in going to higher energies, the Higgs might just be the last new fundamental particle we see discovered in our lifetimes. I think that's exciting.

The mass of the Higgs is almost exactly at the value that makes it most difficult to observe: coincidence, or hint at some interesting underlying math?

Being able to write a theory that describes (nearly) everything simply by consideration of how particles interact-- junctions on a Feynmann diagram -- is a pretty revolutionary physical insight, likely of the same order of magnitude as the transition to Newtonian physics, the kinetic theory of matter, or 1920s-era quantum mechanics. With the Higgs in place, that finally exists.

The LHC is a pinnacle of "big" science, and I don't think there's much enthusiasm about getting an even-larger successor funded. Thus, for now and the medium-term future, the LHC is the cutting edge of particle physics research. The Higgs is the initial goal of the LHC, and if the result is slow in coming, it is nonetheless a significant accomplishment reflecting thousands of "scientist-careers" (like a man-hour) of dedicated work.

I hope those are reasons to care. I did a bit of work on ATLAS (one of the two detectors) a few years ago, so it's doubly-exciting for me.

[Zag]

[Jack_Ian]

[Trojan Horse]

[Zag]

[Lepton*]

Zag, I think I agree with you mostly, but have two minor what-ifs: The potential of the quantum revolution has hardly been realized: consider what might be possible when we start building nanotech on the scale of the Casimir effect. Second, things like nuclear power, lasers, and even fluorescent light bulbs owe their existence to quantum mechanics and/or field theory.

General Relativity, on the other hand... it continues to astonish me that we can even detect it. Never mind practical applications!

The thing with the Higgs Boson's mass being hard to see is a bit convoluted, so I'm going to go slowly for the general audience...

There are a lot of different reactions involving the Higgs, of course. You could have two W bosons collide to make a Higgs, then the Higgs decay into two Z bosons, each of which would decay into two leptons (ie: electrons). So it's 2W -> H -> 2Z -> 4L, Now, you need to conserve energy, and it takes a certain minimum amount of energy to make a Higgs (by E=mc^2). You also need to conserve momentum.

The Tevatron and the detectors at CERN cannot directly observe Ws and Zs, but they're built to (a) see leptons, and (b) determine the energy of the leptons. So you look for "events" in which you see exactly four leptons. You can tell they all come from the same event because the momentum from the four sums up. Next, you check the combined energy of the leptons. If there is no Higgs boson, you'd expect a certain smooth distribution of energies from these leptons: basically, fewer high-energy events because most non-Higgs events have lower energy transfered. But if there is a Higgs boson, there should be a spike in the number of events you'd see at a particular energy (and thus, through E=mc^2, mass).

This 2W -> H -> 2Z -> 4L reaction is only one of many possibilities. There's also one that ends with two leptons and two neutrinos, for example, along with a bunch others. You can use different reactions as "probes" at different possible values of the Higgs mass. For example, if the Higgs were much heavier, a reaction that starts with an electron and an anti-election would produce events -- we would have seen this in the LEP, the predecessor to the LHC at CERN. If the Higgs were lighter, lower-energy 2W reactions would produce events -- we would have seen this at the Tevatron. So, in essence, by using different reactions, we were able to eliminate most of the possibilities for the Higgs mass before the LHC was even built. If I remember correctly, the Tevatron people had even hoped to eliminate the remaining window of possible masses to 2 sigma before they shut down, but I don't think they quite managed it.

It's an interesting coincidence that the Higgs mass is pretty much the most difficult to access. If it were lighter, or heavier, it would be easier (and cheaper, and require lower energy collisions) to detect. Cheekily, we could suggest that God is trying to hide it from us. But it's probably just a coincidence.

standard caveat that, apropos username aside, I know very little about this stuff... grain of salt, etc.

[Zag]

[Lepton*]

I was assuming that designing and building the standard fluorescent light bulb would require some knowledge of how they work. For example, what gases should be used, to which pressures, to maximize the output given the mains voltage? But you're right that this sort of thing could probably be figured out by trial and error.

[extro...*]

Regarding GPS, if we didn't know about relativity, how far off would GPS locations be?

[Zag]

[Lepton*]

extro*, I calculated this a few years ago, but cannot say I remember the results very well. There are corrections from both special relativity and general relativity, with the latter being (surprisingly) larger. I think the uncertainties would have corresponded to distances on the order of 10 metres.

Zag, agreed about the "whoa".