22 July rumor: Higgs at 144 GeV and anti-Higgs at 350 GeV (comment?)

marcus

http://www.math.columbia.edu/~woit/w...#comment-95199
"News from EPS: a higgs at 144 GeV and a anti-Higgs at 350 GeV"


Blogging from the EPS meeting at Grenoble. As of 22 July:
ATLAS and CMS Summarize Their Higgs Searches
http://profmattstrassler.com/2011/07...iggs-searches/

bcrowell

I wouldn't call it a rumor. It seems to be straight from the horse's mouth. However, what we're hearing from the horse's mouth is that basically they do not have statistically significant evidence for the Higgs:

If they had 2.8 sigma after the look-elsewhere effect, it would be worth following up on, but not be particularly exciting. The fact that they have 2.8 sigma before the look-elsewhere says that it means absolutely nothing at all.

Vanadium 50

Absolutely nothing? No, it means 8%.

There are people here who immediately went to work trying to combine everything "by eye". That seems to me to be a real waste of time - it won't convince anyone, and it's impossible to do properly, at least for an outsider. These limits are not completely independent - background cross-sections, for example, are common to both.

What is certainly true now is that the LHC experiments are sensitive to a large region of possible Higgs masses. That was not true a few months ago.

YoungDreamer

Why is the Higgs so hard to find.
I'm very excited about the research going on at the LHC as I have said before I believe that the LHC is going to give us more answers than we have questions for right now.
The technology is very advanced and powerful and should provide a wealth of information that will keep scientist busy for years to come.
But back to my question why is the Higgs-Boson so hard to find?
Isnt the Higgs suppose to exist in large quantities?

YoungDreamer

Do the models or the properties of the Higgs predict that it will be so hard to find?

tom.stoer

b/c the experiments which are designed to produce the Higgs do not ONLY produce the Higgs but zillions of other particles as well; so it's like to find a a pin in a haystack; given the haystack you have to be absolutely sure that you know in detail the quantity of the hay; thenyou subtract the hay from the measurement and what you get is the pin

YoungDreamer

So then could we have already exposed the Higgs and we just havent been able to pick it out of a line up yet, so to speak?

tom.stoer

yes, that's possible

marcus

Nature News reported on this today:
http://www.nature.com/news/2011/1107....2011.435.html
==sample excerpt==
Collider sees tantalizing hint of Higgs
Excess events suggest LHC is homing in on elusive particle.

Geoff Brumfiel

For now, physicists are only willing to call them 'excess events', but fresh data from two experiments at the Large Hadron Collider (LHC) are hinting at something unusual — and it could be the most sought-after particle in all of physics.

Both ATLAS and the Compact Muon Solenoid (CMS) experiments are seeing an unusual surplus of events in a rough mass range of 130–150 gigaelectronvolts (energy and mass are used interchangeably in particle physics). The data are far from conclusive, but physicists believe this could be the first indication of the Higgs particle, believed to be responsible for the masses of other particles. The results were presented this afternoon at the Europhysics Conference on High Energy Physics in Grenoble, France.

Physicists familiar with the experiments urge caution. The new data are a long way from a discovery, says Matthew Strassler, a theoretical physicist at Rutgers University in New Jersey. "I would call it tantalizing."...
==endquote==

Nature magazine is like Science magazine quality-wise. Its journalism is better than most. More reliable than "Science Daily" or "New Scientist". So I tend to think they give a fair picture, to the extent one can at this stage. Better not get your hopes up. But it is interesting to know about nevertheless.

bcrowell

The Nature article is even worse. Doesn't give any quantitative discussion of the statistics.

Vanadium 50

The discussion doesn't exist. ATLAS says the probability a Higgsless dataset will fluctuate to look like what they see is 8%. That's it. CMS did not provide a similar number, and as I said above, you can't just naively combine these results and get anything except nonsense. The experiments are working on a combination; if they are very lucky, we will see it in a month.

bcrowell

This seems to be a response to my posts, but it doesn't seem to relate to what I said. I didn't say anything about combining the results.

Vanadium 50

My point is that we have only one number - ATLAS 8% - and any serious statement about what the LHC sees needs the other number, plus the combination.

mikeph

Could you explain what the 8% represents?

naima

look at the curve in http://en.wikipedia.org/wiki/Standard_deviation

bcrowell

It's the probability that ATLAS would have seen a peak this strong, sticking up above the background somewhere, when in fact background was all there was.

For comparison, the gold standard for claiming discovery of a particle by direct detection is usually taken to be 5 sigma, which is a probability of about 10^-7.

mikeph

So there an 8% chance that there is not a Higgs particle, based on these results?