OPERA neutrino anomaly
Encyclopedia
The OPERA neutrino anomaly is the detection of apparently faster-than-light
neutrinos by the OPERA experiment
as publicly announced in September 2011. The detection is anomalous because speeds exceeding that of light in a vacuum are generally thought to violate special relativity
, a prevailing theory of physics. How to explain the results is debated, with potentially far-reaching implications for our understanding of physics.
The muon neutrino
s in the experiment were sourced at CERN
on the Franco-Swiss border and detected at LNGS
in Gran Sasso, Italy. OPERA researchers used common-view GPS to measure the times and places at which the neutrinos were emitted and detected. As computed, the neutrinos' average time of flight turned out to be less than what light would need to travel the same distance in a vacuum. The OPERA team repeated the measurement with much shorter pulses in a two-week span up to 6 November, which helped measure travel time of each detected neutrino separately, eliminating some sources of error.
Dario Autiero, who leads the OPERA team's analysis of the superluminal result, has stated that further scrutiny and independent tests are necessary to definitely confirm or refute the results. Independent tests by other collaborations are under way.
neutrinos had been observed traveling at faster-than-light
speed. Similar results were obtained using 28 GeV neutrinos, which were observed to test energy dependence. The particles were measured arriving at the detector approximately 1/40,000 times faster than light; their superluminal excess speed as a fraction of lightspeed was (2.48 ± 0.28 (stat.
) ± 0.30 (sys.
)) (approximately 1 in 40,000), with a significance of 6.0 sigma (or , if the distribution is normal). This measure included estimates for both statistical and instrumentation error, though it may have left additional sources of systematic error unaccounted for. For particle physics experiments involving collision data, the standard baseline for a discovery announcement is 5-sigma significance.
The preprint of the research stated "[the observed] deviation of the neutrino velocity from c would be a striking result pointing to new physics in the neutrino sector" and referred to the "early arrival time of CNGS muon neutrinos" as an "anomaly." OPERA collaboration scientist and spokesperson Antonio Ereditato explained that the OPERA team had "not found any instrumental effect that could explain the result of the measurement." James Gillies, a spokesperson for CERN, said on 22 September that the scientists were "inviting the broader physics community to look at what they [had] done and really scrutinize it in great detail, and ideally for someone elsewhere in the world to repeat the measurements."
beam for the measurement. Distance was measured by accurately fixing the source and detector points on a global coordinate system (ETRF2000). CERN surveyors used GPS to measure the source location. On the detector side, the OPERA team worked with a geodesy group from the University of Rome to locate the detector's center with GPS and standard topographical techniques. To topographically link the surface GPS location to the underground detector traffic had to be partially stopped on the access road to the lab. Combining the two location measurements, the researchers calculated the distance to an accuracy of 20 cm within the 730 km path.
CERN's beams department engineers worked with the OPERA team to provide a time measurement between the source at CERN and a point just before the OPERA detector's electronics, using accurate GPS receivers. At Gran Sasso, the GPS receiver was on the surface, and an 8 km fiber cable linked it to the underground detector. Special techniques were used to measure the length of the fiber and its consequent delay, required as part of the overall calculation. Researchers from OPERA measured the remaining delays and calibrations not included in the CERN calculation. To sharpen resolution from the standard GPS 100 ns to the 1 ns range metrology labs achieve, they used Septentrio
’s precise PolaRx2eTR GPS timing receiver which allowed measurement of the time offset between an atomic clock and each of the Global Navigation Satellite System satellite clocks, along with time calibration procedures which allowed for common-view time transfer
. The equipment was taken to the Swiss Metrology Institute (METAS)
for calibration. In addition, highly stable cesium clocks were installed both at LNGS and CERN to cross-check GPS timing and to increase its precision. After OPERA noted the superluminal result, the time calibration was rechecked both by a CERN engineer and the German Institute of Metrology (PTB)
. Time-of-flight was eventually measured to an accuracy of 10 nanoseconds.
) +0.34/ −0.24 (sys.
)). The new significance level became 6.2 sigma. The collaboration has submitted its results for peer review
to the Journal of High Energy Physics
.
supernova restricted 10 MeV anti-neutrino speed to less than 20 parts per billion (ppb) over lightspeed. Fermilab
's MINOS
collaboration (2007) reported results measuring the flight-time of 3 GeV neutrinos yielding a speed , thus faster than that of light at 68% confidence level. However, at 99% confidence level including all margins of error, a range between (slower than light) to (faster than light) was given; thus within the margins of error the result was consistent with both slower and faster than light speed, although the central value was higher than the speed of light.
laureates Steven Weinberg
, and George Smoot
, as well as other physicists not affiliated with the experiment, including Martin Rees, Lawrence Krauss, and Michio Kaku
, expressed skepticism about the accuracy of the original experiment on the basis that the results challenged a long-held theory consistent with the results of many other experiments. Even after OPERA's replication, most in the field disbelieve the light-speed limit has been truly broken. Nevertheless, Ereditato, the OPERA spokesperson, states no one has an explanation that invalidates the experiment's results.
Physicists affiliated with the experiment have refrained from interpreting the result, stating in their paper:
More than 80 papers discussing the experiment have been posted on the arXiv
website for electronic preprint
s. Most try to explain the anomaly theoretically, while a small minority claim the experiment has problems.
CERN theorists held a workshop on October 14 to discuss the OPERA results. Ignatios Antoniadis, head of CERN’s theory group, states the view of CERN theorists was that "there [was] no consistent theoretical model that [could] accommodate the measurement."
(anti-neutrino as against neutrino), flavor (electron versus muon neutrino), energy, and medium of travel (interstellar space versus solid rock).
have predicted superluminal neutrinos would radiate electrons and positrons and lose energy through vacuum Cherenkov effects. This energy attrition is seen neither in the OPERA experiment, nor in the colocated ICARUS experiment using the same CNGS beam as OPERA. This is considered by Cohen and Glashow as a significant challenge to the superluminal interpretation of the OPERA data. Autiero has responded that Cohen and Glashow's premises may not be universally valid. Sergio Bertolucci, director of research at CERN, contends if every new measurement is interpreted with older theories, a new theory is impossible. Cohen and Glashow themselves note, toward the end of their paper, that the energy-loss mechanism they posit may not happen if light itself travels faster than its nominal value in vacuum, for the energy domain considered by the OPERA experiment.
Giacomo Cacciapaglia, a theoretical physicist at King's College London
, has suggested that the neutrinos might take "shortcuts" through extra dimensions
, bypassing the Cohen-Glashow effect. Jorge Páramos, a theoretical physicist at the Higher Technical Institute
in Lisbon, counters that tinkering with the current theory in this way is difficult.
OPERA spokesperson Ereditato says that all the researchers have signed the final submission to JHEP
. Other sources had previously reported that some of the original dissenters had signed that paper, while others who had signed the first paper removed their names from the final one. The current dissenters in the collaboration are concerned the time window for neutrino detection was initially assumed to be 10 ns but revealed by Dario Autiero to be 50 ns after the tests were done. While the discrepancy does not affect the test results, the dissenters consider this poor experimental procedure. They are also unhappy that only a small fraction of the analysis, carried out by Autiero, has been independently checked by others, leaving open the possibility of errors in the analysis.
and the T2K experiment have announced they intend to test the OPERA result in coming months. Fermilab has stated that the detectors for the MINOS project are being upgraded, and new results are not expected until at least 2012. A result based on already recorded data collected in the last five years is expected to be available in mid to end 2012. Fermilab scientists hope to closely analyze and bound the errors in their timing system to achieve a precision of 15 ns, enough to confirm or refute the OPERA early-arrival central value of about 60 ns.
The Borexino
and ICARUS experiments (both located at Gran Sasso) will begin independent checks of OPERA's results in 2012. OPERA itself will cross check clock synchronization between CERN and LNGS, perhaps by using an optical fiber. The researchers will also continue to take data into 2012, expecting to collect around a hundred neutrino events in a couple of months, to improve the accuracy of the results.
(accepted)
Faster-than-light
Faster-than-light communications and travel refer to the propagation of information or matter faster than the speed of light....
neutrinos by the OPERA experiment
OPERA Experiment
The Oscillation Project with Emulsion-tRacking Apparatus is a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. It is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso in Gran Sasso, Italy and uses the CERN Neutrinos...
as publicly announced in September 2011. The detection is anomalous because speeds exceeding that of light in a vacuum are generally thought to violate special relativity
Special relativity
Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
, a prevailing theory of physics. How to explain the results is debated, with potentially far-reaching implications for our understanding of physics.
The muon neutrino
Muon neutrino
The muon neutrino is a subatomic lepton elementary particle which has the symbol and no net electric charge. Together with the muon it forms the second generation of leptons, hence its name muon neutrino. It was first hypothesized in the early 1940s by several people, and was discovered in 1962 by...
s in the experiment were sourced at CERN
CERN
The European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
on the Franco-Swiss border and detected at LNGS
Laboratori Nazionali del Gran Sasso
Laboratori Nazionali del Gran Sasso is a particle physics laboratory of the INFN, situated near the Gran Sasso mountain in Italy, between the towns of L'Aquila and Teramo, about 120 km from Rome. In addition to a surface portion of the laboratory, there are extensive underground facilities...
in Gran Sasso, Italy. OPERA researchers used common-view GPS to measure the times and places at which the neutrinos were emitted and detected. As computed, the neutrinos' average time of flight turned out to be less than what light would need to travel the same distance in a vacuum. The OPERA team repeated the measurement with much shorter pulses in a two-week span up to 6 November, which helped measure travel time of each detected neutrino separately, eliminating some sources of error.
Dario Autiero, who leads the OPERA team's analysis of the superluminal result, has stated that further scrutiny and independent tests are necessary to definitely confirm or refute the results. Independent tests by other collaborations are under way.
Detection
In a March 2011 analysis of their data, scientists of the OPERA collaboration found evidence that neutrinos they produced at CERN in Geneva and recorded at the OPERA detector at Gran Sasso, Italy, had traveled faster than light. The neutrinos were calculated to have arrived 60 ns sooner than light would have if traversing the same distance in a vacuum. After six months of cross checking, on 23 September 2011 they announced that 17 GeVElectronvolt
In physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...
neutrinos had been observed traveling at faster-than-light
Faster-than-light
Faster-than-light communications and travel refer to the propagation of information or matter faster than the speed of light....
speed. Similar results were obtained using 28 GeV neutrinos, which were observed to test energy dependence. The particles were measured arriving at the detector approximately 1/40,000 times faster than light; their superluminal excess speed as a fraction of lightspeed was (2.48 ± 0.28 (stat.
Errors and residuals in statistics
In statistics and optimization, statistical errors and residuals are two closely related and easily confused measures of the deviation of a sample from its "theoretical value"...
) ± 0.30 (sys.
Systematic error
Systematic errors are biases in measurement which lead to the situation where the mean of many separate measurements differs significantly from the actual value of the measured attribute. All measurements are prone to systematic errors, often of several different types...
)) (approximately 1 in 40,000), with a significance of 6.0 sigma (or , if the distribution is normal). This measure included estimates for both statistical and instrumentation error, though it may have left additional sources of systematic error unaccounted for. For particle physics experiments involving collision data, the standard baseline for a discovery announcement is 5-sigma significance.
The preprint of the research stated "[the observed] deviation of the neutrino velocity from c would be a striking result pointing to new physics in the neutrino sector" and referred to the "early arrival time of CNGS muon neutrinos" as an "anomaly." OPERA collaboration scientist and spokesperson Antonio Ereditato explained that the OPERA team had "not found any instrumental effect that could explain the result of the measurement." James Gillies, a spokesperson for CERN, said on 22 September that the scientists were "inviting the broader physics community to look at what they [had] done and really scrutinize it in great detail, and ideally for someone elsewhere in the world to repeat the measurements."
The measurement
The OPERA team relied on the already available CERN Neutrinos to Gran SassoCERN Neutrinos to Gran Sasso
The CERN Neutrinos to Gran Sasso project is a physics project of the European Organization for Nuclear Research . The aim of the project is to analyse the hypothesis of neutrino oscillation by directing a beam of neutrinos from CERN's facilities to the detector of the OPERA experiment at the Gran...
beam for the measurement. Distance was measured by accurately fixing the source and detector points on a global coordinate system (ETRF2000). CERN surveyors used GPS to measure the source location. On the detector side, the OPERA team worked with a geodesy group from the University of Rome to locate the detector's center with GPS and standard topographical techniques. To topographically link the surface GPS location to the underground detector traffic had to be partially stopped on the access road to the lab. Combining the two location measurements, the researchers calculated the distance to an accuracy of 20 cm within the 730 km path.
CERN's beams department engineers worked with the OPERA team to provide a time measurement between the source at CERN and a point just before the OPERA detector's electronics, using accurate GPS receivers. At Gran Sasso, the GPS receiver was on the surface, and an 8 km fiber cable linked it to the underground detector. Special techniques were used to measure the length of the fiber and its consequent delay, required as part of the overall calculation. Researchers from OPERA measured the remaining delays and calibrations not included in the CERN calculation. To sharpen resolution from the standard GPS 100 ns to the 1 ns range metrology labs achieve, they used Septentrio
Septentrio
Septentrio is a designer and manufacturer of high-end multi-frequency GNSS receivers. Its main target is to provide GNSS receiver boards for further system integration by Original Equipment Manufacturers...
’s precise PolaRx2eTR GPS timing receiver which allowed measurement of the time offset between an atomic clock and each of the Global Navigation Satellite System satellite clocks, along with time calibration procedures which allowed for common-view time transfer
Time transfer
Time transfer is a scheme where multiple sites share a precise reference time. Time transfer solves problems such as astronomical observatories correlating observed flashes or other phenomenon with each other, as well as cell phone towers coordinating handoffs as a phone moves from one cell to...
. The equipment was taken to the Swiss Metrology Institute (METAS)
Federal administration of Switzerland
The federal administration of Switzerland is the ensemble of agencies that constitute, together with the Swiss Federal Council, the executive branch of the Swiss federal authorities...
for calibration. In addition, highly stable cesium clocks were installed both at LNGS and CERN to cross-check GPS timing and to increase its precision. After OPERA noted the superluminal result, the time calibration was rechecked both by a CERN engineer and the German Institute of Metrology (PTB)
Physikalisch-Technische Bundesanstalt
The Physikalisch-Technische Bundesanstalt is based in Braunschweig and Berlin. It is the national institute for natural and engineering sciences and the highest technical authority for metrology and physical safety engineering in Germany....
. Time-of-flight was eventually measured to an accuracy of 10 nanoseconds.
Internal replication
Two facets of the result particularly criticized by the neutrino community were the GPS synchronization system and the profile of the proton beam spill that generated neutrinos. OPERA scientists repeated the measurement over the same baseline without any assumptions about the details of neutrino production during the spill, such as energy distribution or production rate, by using a new CERN beam which provided proton pulses of 3 nanoseconds each with up to 524 nanosecond gaps. Beam time was allocated from 21 October to 7 November 2011. Without using the earlier statistical computation, the researchers measured twenty detection events indicating neutrinos had traveled faster than light by 60 ns, with 10 ns uncertainty. The error bounds for the original superluminal speed fraction were tightened further to (2.37 ± 0.32 (stat.Errors and residuals in statistics
In statistics and optimization, statistical errors and residuals are two closely related and easily confused measures of the deviation of a sample from its "theoretical value"...
) +0.34/ −0.24 (sys.
Systematic error
Systematic errors are biases in measurement which lead to the situation where the mean of many separate measurements differs significantly from the actual value of the measured attribute. All measurements are prone to systematic errors, often of several different types...
)). The new significance level became 6.2 sigma. The collaboration has submitted its results for peer review
Peer review
Peer review is a process of self-regulation by a profession or a process of evaluation involving qualified individuals within the relevant field. Peer review methods are employed to maintain standards, improve performance and provide credibility...
to the Journal of High Energy Physics
Journal of High Energy Physics
The Journal of High Energy Physics is a refereed scientific journal in the field of high energy physics, owned by the International School for Advanced Studies and published by Springer.The journal covers the following areas of theoretical and experimental physics:Collider PhysicsUnderground and...
.
Previous measurements
Previous experiments have not detected statistically significant deviations of neutrino speeds from the speed of light; for instance, observations from the SN 1987ASN 1987A
SN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. It occurred approximately 51.4 kiloparsecs from Earth, approximately 168,000 light-years, close enough that it was visible to the naked eye. It could be seen from the Southern...
supernova restricted 10 MeV anti-neutrino speed to less than 20 parts per billion (ppb) over lightspeed. Fermilab
Fermilab
Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...
's MINOS
MINOS
MINOS is a particle physics experiment designed to study the phenomena of neutrino oscillations, first discovered by a Super-Kamiokande experiment in 1998...
collaboration (2007) reported results measuring the flight-time of 3 GeV neutrinos yielding a speed , thus faster than that of light at 68% confidence level. However, at 99% confidence level including all margins of error, a range between (slower than light) to (faster than light) was given; thus within the margins of error the result was consistent with both slower and faster than light speed, although the central value was higher than the speed of light.
Reception by the physics community
NobelNobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
laureates Steven Weinberg
Steven Weinberg
Steven Weinberg is an American theoretical physicist and Nobel laureate in Physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interaction between elementary particles....
, and George Smoot
George Smoot
George Fitzgerald Smoot III is an American astrophysicist, cosmologist, Nobel laureate, and $1 million TV quiz show prize winner . He won the Nobel Prize in Physics in 2006 for his work on COBE with John C...
, as well as other physicists not affiliated with the experiment, including Martin Rees, Lawrence Krauss, and Michio Kaku
Michio Kaku
is an American theoretical physicist, the Henry Semat Professor of Theoretical Physics in the City College of New York of City University of New York, the co-founder of string field theory, and a "communicator" and "popularizer" of science...
, expressed skepticism about the accuracy of the original experiment on the basis that the results challenged a long-held theory consistent with the results of many other experiments. Even after OPERA's replication, most in the field disbelieve the light-speed limit has been truly broken. Nevertheless, Ereditato, the OPERA spokesperson, states no one has an explanation that invalidates the experiment's results.
Physicists affiliated with the experiment have refrained from interpreting the result, stating in their paper:
More than 80 papers discussing the experiment have been posted on the arXiv
ArXiv
The arXiv |Chi]], χ) is an archive for electronic preprints of scientific papers in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance which can be accessed online. In many fields of mathematics and physics, almost all...
website for electronic preprint
Preprint
A preprint is a draft of a scientific paper that has not yet been published in a peer-reviewed scientific journal.-Role:Publication of manuscripts in a peer-reviewed journal often takes weeks, months or even years from the time of initial submission, because manuscripts must undergo extensive...
s. Most try to explain the anomaly theoretically, while a small minority claim the experiment has problems.
CERN theorists held a workshop on October 14 to discuss the OPERA results. Ignatios Antoniadis, head of CERN’s theory group, states the view of CERN theorists was that "there [was] no consistent theoretical model that [could] accommodate the measurement."
OPERA versus SN1987A
The neutrino superluminality reported by MINOS and OPERA appears to be inconsistent with values obtained from SN1987A (see previous measurements). For example, if the SN1987A neutrinos had the same speed as OPERA's, they would have arrived years earlier. However, SN1987A neutrinos differ from the ones detected by OPERA in lepton numberLepton number
In particle physics, the lepton number is the number of leptons minus the number of antileptons.In equation form,so all leptons have assigned a value of +1, antileptons −1, and non-leptonic particles 0...
(anti-neutrino as against neutrino), flavor (electron versus muon neutrino), energy, and medium of travel (interstellar space versus solid rock).
Cohen-Glashow effect
Andrew Cohen and Sheldon Lee GlashowSheldon Lee Glashow
Sheldon Lee Glashow is a Nobel Prize winning American theoretical physicist. He is the Metcalf Professor of Mathematics and Physics at Boston University.-Birth and education:...
have predicted superluminal neutrinos would radiate electrons and positrons and lose energy through vacuum Cherenkov effects. This energy attrition is seen neither in the OPERA experiment, nor in the colocated ICARUS experiment using the same CNGS beam as OPERA. This is considered by Cohen and Glashow as a significant challenge to the superluminal interpretation of the OPERA data. Autiero has responded that Cohen and Glashow's premises may not be universally valid. Sergio Bertolucci, director of research at CERN, contends if every new measurement is interpreted with older theories, a new theory is impossible. Cohen and Glashow themselves note, toward the end of their paper, that the energy-loss mechanism they posit may not happen if light itself travels faster than its nominal value in vacuum, for the energy domain considered by the OPERA experiment.
Giacomo Cacciapaglia, a theoretical physicist at King's College London
King's College London
King's College London is a public research university located in London, United Kingdom and a constituent college of the federal University of London. King's has a claim to being the third oldest university in England, having been founded by King George IV and the Duke of Wellington in 1829, and...
, has suggested that the neutrinos might take "shortcuts" through extra dimensions
Extra dimensions
Several speculative physical theories have introduced extra dimensions of space for various reasons:*Kaluza-Klein theory introduces extra dimensions to explain the fundamental forces other than gravity ....
, bypassing the Cohen-Glashow effect. Jorge Páramos, a theoretical physicist at the Higher Technical Institute
Instituto Superior Técnico
Instituto Superior Técnico is a reputed school of engineering, part of Universidade Técnica de Lisboa . IST is the largest and the most prestigious school of engineering in Portugal...
in Lisbon, counters that tinkering with the current theory in this way is difficult.
Discussions within the OPERA collaboration
Around 15 of the almost 195 researchers in the OPERA collaboration had not signed on to the first preprint of the paper, since they thought the publication was premature and further experimental checks were required.OPERA spokesperson Ereditato says that all the researchers have signed the final submission to JHEP
Journal of High Energy Physics
The Journal of High Energy Physics is a refereed scientific journal in the field of high energy physics, owned by the International School for Advanced Studies and published by Springer.The journal covers the following areas of theoretical and experimental physics:Collider PhysicsUnderground and...
. Other sources had previously reported that some of the original dissenters had signed that paper, while others who had signed the first paper removed their names from the final one. The current dissenters in the collaboration are concerned the time window for neutrino detection was initially assumed to be 10 ns but revealed by Dario Autiero to be 50 ns after the tests were done. While the discrepancy does not affect the test results, the dissenters consider this poor experimental procedure. They are also unhappy that only a small fraction of the analysis, carried out by Autiero, has been independently checked by others, leaving open the possibility of errors in the analysis.
Independent replication
The key test of the result is expected to be replication by an independent experiment. Following OPERA's and CERN's request, both FermilabFermilab
Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...
and the T2K experiment have announced they intend to test the OPERA result in coming months. Fermilab has stated that the detectors for the MINOS project are being upgraded, and new results are not expected until at least 2012. A result based on already recorded data collected in the last five years is expected to be available in mid to end 2012. Fermilab scientists hope to closely analyze and bound the errors in their timing system to achieve a precision of 15 ns, enough to confirm or refute the OPERA early-arrival central value of about 60 ns.
The Borexino
Borexino
Borexino is a particle physics experiment to study low energy solar neutrinos. The primary aim of the experiment is to make a precise measurement of the beryllium-7 neutrino flux from the sun and comparing it to the Standard solar model prediction...
and ICARUS experiments (both located at Gran Sasso) will begin independent checks of OPERA's results in 2012. OPERA itself will cross check clock synchronization between CERN and LNGS, perhaps by using an optical fiber. The researchers will also continue to take data into 2012, expecting to collect around a hundred neutrino events in a couple of months, to improve the accuracy of the results.
Peer reviewed publications
(SpringerLink)(accepted)
External links
- OPERA Main Page
- CNGS Neutrino beam at CERN
- OPERA publications
- Webcast of OPERA neutrino anomaly presentation by Dario Autiero
- arXiv preprints about OPERA
- Resource list of The Net Advance of Physics
- CERN OPERA neutrinos travel faster that light, 22 September 2011, YouTube
- The Neutrinos CERN interview.faster than light Einstein might have been wrong?! HD, YouTube, 23 September 2011
- CERN/LNGS researchers' discussion of how to check the time transfer