Neutrino's Saga - final chapter?

Time of flight difference between the speed of light and the arriving neutrinos. Observe a great difference between the two experiments. Now, we have to wait for the new results of the OPERA experiment, after the cable's problem.

The ICARUS experiment uploaded a paper to the arXiv website with a preprint paper about the neutrinos' velocity, in October 2011, defying the superluminal neutrinos. Now, after the assumption of a problem in a cable, by the OPERA team, ICARUS published a preprint paper that confirms the previous results that neutrinos doesn't travel with a speed superior that the speed of light. 

So, we have to wait for the OPERA results (we need a large number of events and it takes... days), to confirm that neutrinos aren't superluminal.

Here is the abstract:

Measurement of the neutrino velocity with the ICARUS detector at the CNGS beam

The CERN-SPS accelerator has been briefly operated in a new, lower intensity neutrino mode with ~10^12 p.o.t. /pulse and with a beam structure made of four LHC-like extractions, each with a narrow width of ~3 ns, separated by 524 ns. This very tightly bunched beam structure represents a substantial progress with respect to the ordinary operation of the CNGS beam, since it allows a very accurate time-of-flight measurement of neutrinos from CERN to LNGS on an event-to-event basis. The ICARUS T600 detector has collected 7 beam-associated events, consistent with the CNGS delivered neutrino flux of 2.2 10^16 p.o.t. and in agreement with the well known characteristics of neutrino events in the LAr-TPC. The time of flight difference between the speed of light and the arriving neutrino LAr-TPC events has been analysed. The result is compatible with the simultaneous arrival of all events with equal speed, the one of light. This is in a striking difference with the reported result of OPERA [1] that claimed that high energy neutrinos from CERN should arrive at LNGS about 60 ns earlier than expected from luminal speed. 

 Read more in DiscoverMagazine.com, CNet and Wired. 

The Neutrino's Saga - Part 6

Crédito: imgace.com

In opposition of what many people thought, the saga of the neutrinos is not over yet. 

I had already mentioned that these particles conducted between CERN and OPERA, reach the detector sooner than expected. And late last month, I wrote about the experience from ICARUS, whose results contradict those of the OPERA experiment. What is certain is that the team of OPERA has published the second version of this article on arXiv pre-print and the result is: it's the same. Well, almost the same! 

The experiment was repeated with a lower energy, resulting a time difference of 57.8 ns (1 ns = 10^-9 s) against the 61.1 ns obtained previously (that's a difference of 3.3 ns). In addition, concerns about the use in the experiment of the Global Positioning System (GPS) to synchronize the clocks at each start and end of the neutrino beam, are unlikely to be so easily dispelled. The GPS, which was used in both experiments, is  inexperienced in the field of high energy physics and particles.  There are scientists who would like to see the measurement of time checked using another part of the OPERA detector.  This measurement requires a very precise analysis of the time and probably with another type of configuration, to be performed by other entities in future experience (including the MINUS experiment at Fermilab, which was mentioned in a previous post, and is preparing to conduct tests early next year). Still, CERN and Opera will also continue to conduct more experiments to see if there are faults in their calculus or equipment. 

So if you think you can throw the books in physics for the trash, think again. We'll have to wait  to see how this saga will end. 

Other publications: BBC, Science Mag, Washington Post, Nature, Universe Today. 

To learn more about particles can go to the website particleadventure

Source:LiveScience

The Neutrino's saga - turnaround

The results obtained by ICARUS' team says that neutrinos cannot have the speed equal to the speed of light. Indeed, it's smaller than that in three orders of magnitude.

"The saga of the superluminal neutrinos took a dramatic turn today, with the publication of a very simple yet definitive study by ICARUS, another neutrino experiment at the Gran Sasso Laboratories, who has looked at the neutrinos shot from CERN since 2010."

and

"They find that the energy spectrum of the detected neutrino interactions in ICARUS shows a very nice agreement with the expectation for well-behaved light-speed-moving neutrinos. A very dramatic distortion of that spectrum would instead be expected for the speed measured by OPERA, such that indeed ICARUS can place a very tight constraint on the superluminal speed of the CERN neutrinos: consistent with the speed of light, and not larger than that by more than four part in ten billionths. An order of magnitude looser than the limit obtained with the neutrinos from SN1987a, but still quite tight -and certainly excluding without argument the value of 50 millionths measured by OPERA."

Complete article in science20.com
Article (pré-print): arXiv.org

The Neutrino's Saga - Part 5

It seems interesting how the scientific community try to explain the results of the OPERA experiment. See here, here, and here.






Here are the last results:

• Special relativity and clock synchronization; 

"But were the clocks perfectly synchronized?
Keeping time is again the domain of the GPS satellites which each broadcasting a highly accurate time signal from orbit some 20,000km overhead. But is it possible the team overlooked the amount of time it took for the satellite signals to return to Earth? In his statement, van Elburg says there is one effect that the OPERA team seems to have overlooked: the relativistic motion of the GPS clocks.
Sure, radio waves travel at the speed of light, so what difference does the satellite position make? The truth is, it doesn’t.. but the time of flight does. Here we have a scenario where one clock is on the ground while the other is orbiting. If they are moving relative to one another, this calculation needs to be included in the findings. The orbiting probes are positioned from West to East in a plane inclined at 55 degrees to the equator… almost directly in line with the neutrino flight path. This means the clock on the GPS is seeing the neutrino source and detector as changing."

• Times Of Flight Between A Source And A Detector Observed From A GPS Satellite;

"But there is an additional subtlety. Although the speed of light is does not depend on the the frame of reference, the time of flight does. In this case, there are two frames of reference: the experiment on the ground and the clocks in orbit. If these are moving relative to each other, then this needs to be factored in."

paper: http://arxiv.org/abs/1110.2685

• Cautionary Tale From Neutrinoland (thinking about all the explanations and Physics behind in two published articles)
• No So Fast, Neutrinos (MIT)

"Hughes and Wilczek both guess that scientists will most likely approach the neutrino announcement with a variety of new experiments and do tests with different baselines.
“I would say there’s a 98 percent chance this is a systematic error,” Hughes said."

• Light speed

The recent news of neutrinos moving faster than light might have got everyone thinking about warp drive and all that, but really there is no need to imagine something that can move faster than 300,000 kilometres a second. Indeed, the whole idea is illogical.

• Time reversal: A simple particle could reveal new physics

(PhysOrg.com) -- A simple atomic nucleus could reveal properties associated with the mysterious phenomenon known as time reversal and lead to an explanation for one of the greatest mysteries of physics: the imbalance of matter and antimatter in the universe.

The Neutrino's Saga - Part 4

The OPERA detector

Light speed
The recent news of neutrinos moving faster than light might have got everyone thinking about warp drive and all that, but really there is no need to imagine something that can move faster than 300,000 kilometres a second. Indeed, the whole idea is illogical.

CERN and colliding theories
Findings that showed faster-than-light travel were released to the public too soon.

New theories emerge to disprove OPERA faster-than-light neutrinos claim
(PhysOrg.com) -- It's been just two weeks since the Oscillation Project with Emulsion-tRacking Apparatus (OPERA) team released its announcement claiming that they have been measuring muon neutrinos moving faster than the speed of light, causing an uproar in the physics community. Since that time, many papers (perhaps as many as 30 to the preprint server arXiv alone) have been published seeking ways to discredit the findings. Thus far though, only two seem credible.

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