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New Particle Resembling Long-Sought Higgs Boson Uncovered at Large Hadron Collider

As you’ve likely heard, both the ATLAS and CMS teams at the Large Hadron Collider believe they’ve found the Higgs Boson:

Crucially, both teams’ findings appear exceptionally robust. In physics terms, evidence for a new particle requires a “3-sigma” measurement, corresponding to a 1-in-740 chance that a random fluke could explain the observations, and a claim of discovery requires a 5-sigma effect, or a 1-in–3.5 million shot that the observations are due to chance. In December representatives of the two experiments had announced what one called “intriguing, tantalizing hints” of something brewing in the collider data. But those hints fell short of the 3-sigma level. The new ATLAS finding met not just that level of significance but cleared the gold standard 5-sigma threshold, and CMS very nearly did as well, with a 4.9-sigma finding. […]

The newfound particle fits the bill for the Higgs boson, but the researchers cautioned that more work is needed to compare the properties of the particle to those predicted for the Higgs. After all, the LHC’s detectors cannot identify the Higgs directly. The LHC accelerates protons to unprecedented energies of four trillion electron-volts (4 TeV) before colliding a clockwise-traveling proton beam with a counterclockwise beam. From the smash-up new particles emerge, some of them existing for just an instant before decaying to other particles.

Full Story: Scientific American: New Particle Resembling Long-Sought Higgs Boson Uncovered at Large Hadron Collider

Previously: CERN May Have Found the Higgs Boson Particle, but Don’t Get Too Excited Yet

In Case You Missed It Last Week: LHC Reports Discovery of Its First New Particle

The Chi_b (3P) is a more excited state of Chi particles already seen in previous collision experiments, explained Prof Roger Jones, who works on the Atlas detector at the LHC.

“The new particle is made up of a ‘beauty quark’ and a ‘beauty anti-quark’, which are then bound together,” he told BBC News.

“People have thought this more excited state should exist for years but nobody has managed to see it until now.

“It’s also interesting for what it tells us about the forces that hold the quark and the anti-quark together – the strong nuclear force. And that’s the same force that holds, for instance, the atomic nucleus together with its protons and the neutrons.”

BBC: LHC reports discovery of its first new particle

LHC Disproves One Form of String Theory

LHC CMS Experiment graph

The results continue to pour out of the LHC’s first production run. This week, the folks behind the CMS detector have announced the submission of a paper to Physics Letters that describes a test of some forms of string theory. If this form of the theory were right, the LHC should have been able to produce small black holes that would instantly decay (and not, as some had feared, devour the Earth). But a look at the data obtained by CMS shows that a signature of the black holes’ decay is notably absent. […]

Contrary to some reports, this result doesn’t mean the death of string theory, only the particular flavor that predicted black holes at these energies. Eliminating some models is a critical process of narrowing down what’s possible, but most theoretical constructs have a range of possible models, and string theory is no different. In fact, it’s entirely possible that the ADD model was generated simply because physicists were looking for something they could possibly test in the LHC.

Ars Technica: LHC spots no black holes, eliminates some versions of string theory

The First New Discovery by the Large Hadron Collider?

Tracks from CMS collisions

Interesting stuff from the CMS Experiment:

After nearly 6 months of smashing particles, the Large Hadron Collider has seen signs of something entirely new. Pairs of charged particles produced when two beams of protons collide seem to be associated with each other even after they fly apart. […]

It’s as if two particles somehow talked to each other when they were produced, the physicists said. This phenomenon has never been seen before in proton-proton collisions, though it resembles something seen at RHIC (the Relativistic Heavy Ion Collider) at Brookhaven National Laboratory in New York. That effect was interpreted to be from the creation of hot dense matter shortly after the collisions.

The CMS team collected the data in mid-July, and spent the rest of the summer trying to blame it on an error or artifact of the data.

Wired Science: LHC Detects Evidence of New Physics

See also:

A photo tour of the Large Hadron Collider

Budget cuts force CERN to shut accelerators for year

CERN

Bummer:

CERN had previously announced that the LHC would not run in 2012 “for purely technical reasons.” It said it would now also shut down all of its other accelerators in 2012 as it focuses its resources on the most critical research.

“The whole CERN accelerator complex will now join the LHC in a year-long shutdown,” the institute said in a statement. “CERN management considers this a good result for the laboratory given the current financial environment.”

Reuters: Budget cuts force CERN to shut accelerators for year

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