New Bounds On the Higgs Boson Mass

As the LHC continues to run at half power for the next year+, the US-based Tevatron continues to crank out results. Reader hweimer writes "Three new papers in Physical Review Letters present the latest results for the Higgs boson mass coming from Fermilab's Tevatron. The new data mandates that the Higgs boson mass within the standard model lies between 115 and 150 GeV." A year back we discussed the Tevatron's previous shrinking of the search space for the Higgs "God particle."

Fermilab Bastards.

[Anonymous Coward]

The more I hear about Tevatron's new discoveries - and the slowing progress of the LHC; the more I think Fermilab had something to do with LHCs 'demise'

To be clear what this means.

[JoshuaZ]

These are bounds for the mass of the Higgs boson assuming it exists. If it doesn't exist, this data is meaningless. What will presumably eventually happen is that we'll narrow the mass down to a very tiny bound (if it exists) which would be strong evidence for its existence. Or we might detect the Higgs boson using some other methods and higher energies, such as those at the LHC. Alternatively, if the Higgs boson doesn't exist then we may end up narrowing the upper and lower bounds until they cross each other. In that case the Standard Model will be wrong and we'll have an interesting day.

Re:wasteful

[hedwards]

As opposed to wasting trillions of dollars to destabilize the middle east? Yeah, that's a useful expenditure of tax payer dollars. Perhaps next year we can pay to remove all references to electrons from the chemistry text books while we're at it.

Seriously, the applications for a lot of this stuff doesn't become apparent until after it's been discovered, I'm not sure what people thought they'd be able to do with Maxwell's equations, but I doubt very much that they thought we'd get super colliders and computers out of it.

Re:Aw shucks...

[hedwards]

Note, they possibly could still do it, it's not out of the realm of possibility that the higgs boson is going to require more than fermilab can throw at it. Additionally if it turns out that the higgs boson doesn't exist, you're probably going to want the LHC and possibly something bigger to really nail it down. Rather than just eliminate the larger sizes. I don't expect that this sort of research will really settle the question unless there's a positive result and somebody actually discovers it.

I'm lost.

[DJRumpy]

I would imagine this is how my family and friends feel when I start speaking computer gibberish. I'd consider myself relatively competent to understand basic principles like gravity, mass, weight, etc, but can someone dumb this down?

http://en.wikipedia.org/wiki/Standard_Model [wikipedia.org]

I know that's probably a hopeless request without some sort of basis in this field, but can someone give the "particle physics for dummies" equivalent here?

I get the impression this is a hunt for some as yet unknown particle?

The "particles" word is unfortunate

[Kupfernigk]

Physicists have adopted the word "particles" to mean all kinds of different things, and I think this is a lot of the problem. It made sense when electrons, protons and neutrons first were discovered, because they had a relatively familiar kind of pointlike behavior even though this was not really correct. I have a nuclear physics textbook from the 1930s, and it is really interesting to see the state of confusion they were in at the time. (Memo to global warming denialists: there was also a lot of discussion about whether this stuff was or was not "real" and whether the experiments meant anything. This came to a sudden stop around mid-1945, for some obscure reason. However, I digress.)

Most people use the word "particle" to mean a small solid object, and I think it is fair to say that quarks, gluons, and the Higgs can't meaningfully be categorised in this way. It is not surprising that early mathematical physicists often emphasised concentrating on the wave equations and not trying to assign physical meanings.

Re:Bounds are Complicated

[Rich0]

So at just 2 sigma, 1 in 20 times you will get it wrong/fail. I would hope that in medicine and biochemistry, where it matters, that they do use 3 sigma certainty.

I hate to burst your bubble, but in medicine you can't create cancer patients by blasting metals with cathode rays or however you make your particles in your accelerators. You also can store a sample of a quintillion patients in an ion trap. Sample sizes are just a tiny bit smaller in most clinical trials when compared to particle colliders.

Clinical trials (whether on drugs or other medical techniques) are very rudimentary techniques for determining the effectiveness of treatments, but they're the best we have, and many medical techniques don't even get this level of rigor. Usually their results are only significant at the 95% confidence level, which means that 1 out of every 20 things we "know" in medicine could be completely wrong. Additionally, a significant results often means that there is a barely measurable difference between a treatment and a placebo - the placebo might cure cancer 20% of the time, and the pill might cure it 30% of the time.

If we just lied to patients and gave them all sugar pills I doubt our standards of health care would drop enough to even be measured, which is pretty sad to think about.

Re:A couple of errors here...

[zmooc]

Apart from that you're completely right, I couldn't resist the urge to come up with some far-fetched counterarguments:Pp

1) That's not quite true. It is perfectly possible to cool something with "superhot" laser beams; no need to have something even cooler. Therefore, reaching absolute zero is not impossible by that definition. It is only the law of entropy that prevents us from reaching absolute zero. Or so it says.

2) Since we're reached the purely theoretical/philosophical discussion... zero-point energy only changes with time. So if you'd be able to stop time, it would be possible to stop all molecular motion (which also follows from the definition of motion and time anyway;)). But then again, without time, one cannot observe. We would not even notice if time stopped, maybe it just paused for quite some "time" ;-PPp

3) I believe (but am not sure) we merely don't know how to stop or slow photons (in a vacuum, that is). No known force can do it nor does there appear to be a gap in our knowledge in which such a force might eventually be found. So it is very likely that it is impossible indeed, but as far as I'm aware there's no proof of that.

Never say never;-)