Aurion Mission: Aug 27, 2011

Saturday, August 27, 2011

LHC results put supersymmetry theory 'on the spot'

Supersymmetry Supersymmetry predicts the existence of mysterious super particles.

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Results from the Large Hadron Collider (LHC) have all but killed the simplest version of an enticing theory of sub-atomic physics.
Researchers failed to find evidence of so-called "supersymmetric" particles, which many physicists had hoped would plug holes in the current theory.
Theorists working in the field have told BBC News that they may have to come up with a completely new idea.
Data were presented at the Lepton Photon science meeting in Mumbai.
They come from the LHC Beauty (LHCb) experiment, one of the four main detectors situated around the collider ring at the European Organisation for Nuclear Research (Cern) on the Swiss-French border.
According to Dr Tara Shears of Liverpool Liverpool University, a spokesman for the LHCb experiment: "It does rather put supersymmetry on the spot".

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There's a certain amount of worry that's creeping into our discussions”
End Quote Dr Joseph Lykken Fermilab
The experiment looked at the decay of particles called "B-mesons" in hitherto unprecedented detail.
If supersymmetric particles exist, B-mesons ought to decay far more often than if they do not exist.
There also ought to be a greater difference in the way matter and antimatter versions of these particles decay.
The results had been eagerly awaited following hints from earlier results, most notably from the Tevatron particle accelerator in the US, that the decay of B-mesons was influenced by supersymmetric particles.
LHCb's more detailed analysis however has failed to find this effect.
Bitten the dust
This failure to find indirect evidence of supersymmetry, coupled with the fact that two of the collider's other main experiments have not yet detected supersymmetic particles, means that the simplest version of the theory has in effect bitten the dust.
Lead ion collisions Collisions inside the LHC should have found some evidence of Supersymmetry by now
The theory of supersymmetry in its simplest form is that as well as the subatomic particles we know about, there are "super-particles" that are similar, but have slightly different characteristics.
The theory, which was developed 20 years ago, can help to explain why there is more material in the Universe than we can detect - so-called "dark matter".
According to Professor Jordan Nash of Imperial College London, who is working on one of the LHC's experiments, researchers could have seen some evidence of supersymmetry by now.
"The fact that we haven't seen any evidence of it tells us that either our understanding of it is incomplete, or it's a little different to what we thought - or maybe it doesn't exist at all," he said.
The timing of the announcement could not be worse for advocates of supersymmetry, who begin their annual international meeting at Fermilab, near Chicago, this weekend.

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Supersymmetry... has got symmetry and its super - but there's no experimental data to say it is correct”
End Quote Professor George Smoot Nobel Laureate
Dr Joseph Lykken of Fermilab, who is among the conference organisers, says he and others working in the field are "disappointed" by the results - or rather, the lack of them.
"There's a certain amount of worry that's creeping into our discussions," he told BBC News.
The worry is that the basic idea of supersymmetry might be wrong.
"It's a beautiful idea. It explains dark matter, it explains the Higgs boson, it explains some aspects of cosmology; but that doesn't mean it's right.
"It could be that this whole framework has some fundamental flaws and we have to start over again and figure out a new direction," he said.
Down the drain
Experimental physicists working at the LHC, such as Professor Nash, say the results are forcing their theoretical colleagues to think again.
"For the last 20 years or so, theorists have been a step ahead in that they've had ideas and said 'now you need to go and look for it'.
"Now we've done that, and they need to go scratch their heads," he said.
That is not to say that it is all over for supersymmetry. There are many other, albeit more complex, versions of the theory that have not been ruled out by the LHC results.
These more complex versions suggest that super-particles might be harder to find and could take years to detect.
Some old ideas that emerged around the same time as supersymmetry are being resurrected now there is a prospect that supersymmetry may be on the wane.
One has the whimsical name of "Technicolor".
According to Dr Lykken, some younger theoretical physicists are beginning to develop completely novel ideas because they believe supersymmetry to be "old hat" .
"Young theorists especially would love to see supersymmetry go down the drain, because it means that the real thing is something they could invent - not something that was invented by the older generation," he said.
And the new generation has the backing of an old hand - Professor George Smoot, Nobel prizewinner for his work on the cosmic microwave background and one of the world's most respected physicists.
"Supersymmetry is an extremely beautiful model," he said.
"It's got symmetry, its super and its been taught in Europe for decades as the correct model because it is so beautiful; but there's no experimental data to say that it is correct."
Millions in US urged to flee path of Hurricane Irene

More than two million people on the US east coast have been told to evacuate their homes as Hurricane Irene nears, packing winds of 90mph (150km/h).

The mayor of New York has ordered an unprecedented evacuation of a quarter of a million people living in low-lying parts of the city.
Seven states from North Carolina to Connecticut have declared emergencies ahead of Irene's arrival.
US President Barack Obama has warned Irene could be "a historic hurricane".
He has urged people in the projected path of Hurricane Irene - the first hurricane of the Atlantic season - to take precautions.
"Don't wait, don't delay. We all hope for the best, but we have to be prepared for the worst. All of us have to take this storm seriously," he said on Friday, before cutting short his holiday in Martha's Vineyard, an island on the Massachusetts coast, a day early to head back to Washington.
The National Hurricane Center has downgraded Irene from a category two to a category one hurricane but says it is still packing hurricane-force winds of 90mph (150km/h) that extend outwards some 90 miles (150km). Tropical-force winds extend as far as 290m (465km).
The NHC says Irene is expected to weaken in strength after it hits the coast of North Carolina later on Saturday morning, but is forecast to remain a hurricane as it moves north along the mid-Atlantic coast on Sunday.

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President Obama: "If you're in the way of this hurricane you should be preparing now"
More than 200,000 people have already evacuated coastal parts of North Carolina as high waves and strong winds began to lash islands just off the mainland. Residents hoping to ride out the storm have stocked up on food, water and fuel.
Forecasters have warned of "extremely dangerous" storm surges in parts of North Carolina that could raise water levels by as much as 11 ft (3.35m).
"Stores are busy, petrol stations are running dry but thankfully I prepared myself last night with supplies," said Alex Schlesinger of Virginia Beach in the neighbouring state of Virginia, also in the hurricane's path.
Grounded flights

Tens of thousands of people were also on the move in parts of Delaware, Maryland, New Jersey and New York City after mandatory evacuations were ordered for people living in low-lying areas.
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Parts of New York City affected include the financial district around Wall Street in Manhattan. Hospitals in affected areas of the city had begun evacuating patients.
"We've never done a mandatory evacuation before and we wouldn't be doing it now if we didn't think this storm had the potential to be very serious," said Mayor Michael Bloomberg.
New York Governor Andrew Cuomo said the state's transport network, including the New York City subway, would close from midday (16:00 GMT) on Saturday.
Airports operating by the Port Authority of New York and New Jersey - including JFK, La Guardia and Newark - will close to arriving flights at the same time.
However, the airports will remain open for departing flights until further notice.
In Washington DC, Sunday's dedication of the new memorial for Martin Luther King Jr - which President Obama had been expected to attend - has been postponed until at least September.

Manhattan, like other parts of the east coast, braces itself for Hurricane Irene The power company serving the Washington area advised of "potential widespread power outages" at the weekend.
Amtrak, the US rail network, announced it was cancelling services between Washington and Boston from Saturday, having already suspended operations south to Virginia and beyond.
The Pentagon has loaded 200 trucks with emergency supplies, and 100,000 National Guard troops are on standby, the BBC's Steve Kingstone in New York reports.
The American Red Cross said it was preparing dozens of emergency shelters along the east coast.
The eastern seaboard is the most densely populated corridor in the US, with more than 65 million people living in major cities along the coast from Washington to Baltimore, Philadelphia, New York and Boston.
States of emergency have been declared in North Carolina, Maryland, Virginia, Delaware, New Jersey, New York and Connecticut.
"We're going to have damages, we just don't know how bad," Craig Fugate, head of the US Federal Emergency Management Agency, told the Associated Press news agency.
"This is one of the largest populations that will be impacted by one storm at one time."
If Irene hits New York and New England at category two, it will be the region's strongest storm since Hurricane Bob glanced off Massachusetts in 1991, and Hurricane Gloria, which caused extensive damage to New York City in 1985.

Are you in the path of Hurricane Irene? How are you preparing for the storm? You can get in touch using the form below:
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