Has the Higgs Been Discovered? Physicists Gear Up for Watershed Announcement

[n2doc]

Rumors are flying about a December 13 update on the search for the long-sought Higgs boson at Europe's Large Hadron Collider
By Davide Castelvecchi | December 8, 2011 |


snip:

The talks were announced last week; true to form, the particle physics rumor mill shifted into high gear, and by the weekend multiple anonymous sources had leaked consistent information, according to several bloggers, including Peter Woit, Lubos Motl and Philip Gibbs. Both experiments are said to have seen evidence of the long-sought Higgs, pointing to a particle mass of around 125 billion electron volts, or 125 GeV. (125 billion electron volts is roughly the mass of 125 hydrogen atoms.)* Such results would not constitute an ironclad discovery quite yet, being below the required "5 sigma," a measure of statistical reliability. But the two experiments are rumored to have seen signals of 2.5 sigma and 3.5 sigma, which together would give a strong hint. (Three sigmas would correspond to a one-in-370 chance of the finding being a statistical quirk, although in particle physics experiments it is not uncommon for 3-sigma results to vanish.)

Previous rounds of data analysis from the LHC as well as from its U.S. predecessor, Fermilab's Tevatron, had narrowed the Higgs mass range down to somewhere between 115 and 140 GeV. But the new announcement would constitute the first time that both LHC experiments had made a precise and consistent estimate of the mass.

Even before the data are out, theoretical physicists around the world are working out the possible implications. Some have pointed out that a value of 125 GeV would be good news for supersymmetry, a theory that predicts that each particle would have a heavier partner known as a superparticle (at least for particles within the framework of the Standard Model of particle physics, the currently accepted description of the subatomic world). "Most supersymmetric models put a Higgs below 140 or so," says Matt Strassler of Rutgers University. Supersymmetry has long been a favorite candidate for extending the Standard Model, because it would answer numerous open questions, beginning with the nature of dark matter, the unseen mass that keeps galaxies rotating faster than they otherwise would.


rest of article
http://www.scientificamerican.com/article.cfm?id=higgs-lhc

[BadGimp]

1. speak english dammit

please - can you translate for us neophytes?

thank you in advance ...

[PoliticAverse]

3. We're all bosons on this bus. n/t

[DetlefK]

10. Actually, we're Fermions, as only one person can sit on a seat.

You can't stockpile people on a seat up to infinity...

[snagglepuss]

16. The Guardian has the clearest explantions I've read.

snip

The Higgs boson is the last remaining piece of the Standard Model, the set of mathematical rules that describe how all the known particles in nature interact with one another.



snip


The Higgs boson is the signature particle of a theory that says the vacuum of space is filled with an invisible field that stretches to every corner of the universe. The field is thought to give mass to fundamental particles, such as the quarks and electrons that make up atoms. Without the field, or something like it, these particles would weigh nothing at all and hurtle around at the speed of light. There would be no atoms as we know them, nor stars or planets.






http://www.guardian.co.uk/science/2011/dec/09/higgs-boson-hunters-lhc

[Grown2Hate]

2. Can't WAIT for Dec 13th!!! NT

[mike_c]

4. how could a particle with the mass of 125 hydrogens be so elusive...?

Disclaimer-- I'm a biologist, not a physicist! But that sounds like a pretty massive particle! Correct me if I'm mistaken, but isn't that essentially the mass of iodine atoms?

[caraher]

6. Well, the thing is, they're not just flying around to be detected

The W and Z bosons discovered around 30 years ago were 80-90 times the mass of a hydrogen atom, but under ordinary circumstances they are "virtual" particles which pretty much by definition cannot be directly detected. So first of all, you need to actually produce them, however briefly, as "real" particles.

How easy that is depends on the details of what interactions it participates in and all the ways that the two energetic particles you smash together can fall apart into other particles. It's not always the actual mass of the particle that stands in your way; the top quark is even heavier at around 173 GeV and was found over 15 years ago.

Another issue is detection, which frequently is not direct anyway, but comes from looking for "signatures" in the form of characteristic particles arising from its decay. In a similar way, you have to work out all the ways what you're looking for might appear, as well as all the processes that mimic what you'd expect to see from the particle you're looking for.

So I guess what I'm saying is, there's no good layman's rule of thumb for what makes something like the Higgs elusive. Large mass can be a useful explanation of why a given particle was not detected in the past, but there can be other factors that make a detection extremely challenging.

[eridani]

5. Alpine Kat sez--

If the Higgs exists they ought to see it right away
If it doesn't, the scientists will finally say
"There is no Higgs! We need new physics to account for why
Things have mass--something in our standard model went awry."

[caraher]

8. Which I suppose is why Gordon Kane says

"It's impossible to be excited enough."

When I was an in grad school, Kane gave a talk on his work whose theme was, basically, all that's left in physics is finding the mass of the Higgs boson and detecting the particles predicted by supersymmetry. So this is, like, half of all there remains to do in physics ;)

[jimlup]

9. Gordie was my E&M professor...

We hated him. He ... basically he just read from John David Jackson's Electrodynamics. Nobody bothered to go to class. But he's a fine enough guy in the office. I got to know him a little bit later as a grad student researcher in the department.

[girl gone mad]

19. SUSY is all but dead..

so at least there's that.

[DetlefK]

11. link to "Large Hadron Rap" by Alpine Kat

http://www.youtube.com/watch?v=j50ZssEojtM

[eridani]

12. A true nerdcore rap classic

I was too lazy to look up the link--thanks for posting it.

[Odin2005]

7. YAY!!!

[hue]

13. Consistant signals/signatures at approx 125 GeV from 2 seperate

experiments are more than coincidence. Confirmation will come next year, but most physicists believe they are coming close to finding the Higgs. This will result in a leap in our understanding of how our universe came to be and take us to physics beyond the Standard Model. It is a huge--massive--confirmation that we are on the right path! :-)

[Ready4Change]

14. I'll be almost disappointed if they 'find' it.

Not finding it would be exciting. All those physicists going "WTH?" An explosion of new theories, and/or dusting off of old ones, re-casting the picture of how things work, etc.

If, however, this is a sign that they are caging in the HB, what then? What can be done with that knowledge? What new avenues of understanding can be traveled? What would/will be next in physics?

[hue]

15. It looks like they've found it, but not at Sigma 5 level yet.

Next is physics beyond the SM; Supersymmetry, Dark Matter, String Theory etc. This is where Einstein's theories break down.

[Name removed]

17. Deleted message

Message removed by moderator. Click here to review the message board rules.

[girl gone mad]

18. I've really been taking this news hard since last week.

It feels like someone died.

:(

[jkent26943xs]

20. interesting