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Fisica: superata la velocita' della luce

22 Settembre 2011 20:23 SCIENZE E TECNOLOGIE

(ANSA) - ROMA - I neutrini superano la velocita' della luce. Lo dimostra, a quanto si apprende, l'esperimento Cngs, nel quale un fascio di neutrini viene lanciato dal Cern di Ginevra e raggiunge i Laboratori Nazionali del Gran Sasso, dell'Infn. La conferma ufficiale del Cern arrivera' forse domani. Se confermato il risultato rompera' uno dei capisaldi della fisica contemporanea, quello dell'impossibilita' di superare la velocita' della luce, previsto dalla Teoria della Relativita' di Albert Einstein.

http://www.corriere.it/notizie-ultima-o ... 0840.shtml



where's ur relativity nao?

CERN scientists 'break the speed of light'
Nothing is supposed to go faster than light. But on Thursday scientists at the world's largest physics lab say they clocked subatomic particles doing just that.

7:46PM BST 22 Sep 2011

If true, it would break - if not severely twist - a fundamental pillar of physics.

Scientists say that neutrinos - one of the strangest well-known particles in physics - smashed past the cosmic speed barrier of 186,282 miles per second (299,792 kilometres).

The European Organization for Nuclear Research, CERN, says the speeds were detected in a neutrino beam fired from Geneva to a lab 454 miles (730 kilometres) away in Italy.

Baffled scientists are asking others to independently verify the measurements or find other more mundane explanations for the measured speed.

Speed-of-light experiments yield baffling result at LHC
By Jason Palmer Science and technology reporter, BBC News
Albert Einstein Einstein's relativity theory holds that nothing can exceed the speed of light


Puzzling results from Cern, home of the LHC, have confounded physicists - because it appears subatomic particles have exceeded the speed of light.

Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a tiny fraction of a second early.
The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.
In the meantime, the group says it is being very cautious about its claims.
"We tried to find all possible explanations for this," said report author Antonio Ereditato of the Opera collaboration.
"We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.
"When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"
Caught speeding?
The speed of light is the Universe's ultimate speed limit, and much of modern physics - as laid out in part by Albert Einstein in his theory of relativity - depends on the idea that nothing can exceed it.
Thousands of experiments have been undertaken to measure it ever more precisely, and no result has ever spotted a particle breaking the limit.
But Dr Ereditato and his colleagues have been carrying out an experiment for the last three years that seems to suggest neutrinos have done just that.
Neutrinos come in a number of types, and have recently been seen to switch spontaneously from one type to another.
The team prepares a beam of just one type, muon neutrinos, sending them from Cern to an underground laboratory at Gran Sasso in Italy to see how many show up as a different type, tau neutrinos.
In the course of doing the experiments, the researchers noticed that the particles showed up a few billionths of a second sooner than light would over the same distance.
The team measured the travel times of neutrino bunches some 15,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery.
But the group understands that what are known as "systematic errors" could easily make an erroneous result look like a breaking of the ultimate speed limit, and that has motivated them to publish their measurements.
"My dream would be that another, independent experiment finds the same thing - then I would be relieved," Dr Ereditato said.
But for now, he explained, "we are not claiming things, we want just to be helped by the community in understanding our crazy result - because it is crazy".
"And of course the consequences can be very serious."

FTW

quindi da qualche parte mi sto sbattendo quella di 6 anni fa
benebene
e se corro forte allora magari la ritrovo

Comunque.. come funziona la misurazione dell'intervallo di tempo emissione/rilevamento?

CERN says a neutrino beam fired from a particle accelerator near Geneva to a lab 454 miles (730 kilometers) away in Italy traveled 60 nanoseconds faster than the speed of light. Scientists calculated the margin of error at just 10 nanoseconds, making the difference statistically significant. But given the enormous implications of the find, they still spent months checking and rechecking their results to make sure there was no flaws in the experiment. "We have not found any instrumental effect that could explain the result of the measurement," said Antonio Ereditato, a physicist at the University of Bern, Switzerland, who was involved in the experiment known as OPERA. The researchers are now looking to the United States and Japan to confirm the results. - physorg

Measurement of the neutrino velocity with the OPERA detector in the CNGS beam

OPERA

(Submitted on 22 Sep 2011)

The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.

Da arxiv.org:

Old. E ci voleva pure l'esperimento?
Si sapeva da eoni

...sempre toni allarmistici...come se la fisica sia un sistema improvvisato...queste news sparate alla massa pecorona servono solo ad alimentare idee legate a stupidi miti e superstizioni...non crollerà un bel cazzo di nulla...

e che cambia quindi?

Più che altro perchè è successo in Italia

Il problema è che mi pare un tantino strano considerare i neutrini come semplici corpi puntiformi a cui applicare v=Ds/Dt, anche perchè è bene ricordare per evitare il sensazionalismo che il limite relativistico si applica alla velocità di gruppo quando si utilizzano modelli ondulatori come nel mondo microscopico, non a quella di una componente che può BENISSIMO superare la velocità della luce.