The Phantom of the Opera: OPERA is repeating the faster-than-light neutrino experiment following the criticisms

The saga of the tachyon neutrino continues. As you remember, the Oprah group published a pre-print article on arXiv - which is a database of non-scientific articles. The decision to repeat the experiment means that the group will delay submitting its result in an article to the Shefit journal by about a month.

The OPERA group, the Oscillation Project with Emulsion-Tracking Apparatus, which made headlines around the world last month when it announced it had allegedly observed neutrinos traveling faster than light, decided to make new, very precise measurements to re-examine its controversial result. The measurements will probably be carried out next week and will probably last for ten days.

The saga of the tachyon neutrino continues. As you remember, the Oprah group published a pre-print article on arXiv - which is a database of non-scientific articles. The decision to repeat the experiment means that the group will delay submitting its result in an article to the Shefit journal by about a month.

This step also followed the wave of articles that flowed into arXiv - including forum discussions and blog posts - where most of them strongly disagreed with the group's claim that the speed of neutrinos can exceed that of light by even a few nanoseconds. The strong objection was especially to the claim that perhaps this result was announced too quickly before it was thoroughly tested.

The next time you think you may have discovered that "Einstein was wrong", first go back to the lab a few times before you go out with this announcement, because the arXiv server will be filled with masses of opposing and angry articles if you don't.
The OPERA detector is located under Mount Gran Sesso in central Italy. This detector studies the properties of neutrinos that travel 730 kilometers through the Earth's crust after being created at the CERN laboratory in Geneva. In a paper by the OPERA group uploaded to the arXiv repository on September 22, the group reported that the neutrinos observed between 2009 and 2011 appeared to be moving faster than light, arriving about 60 nanoseconds earlier than expected from the exact calculations.

Some of the members of the 160-person group believe that additional tests are needed to be completely sure that indeed the result obtained is not due to a measurement error. Indeed, there was a heated debate within the group itself, whether these additional tests should be performed before the article is submitted for publication to the Shefit journal.

Out of the group some of the 30 group leaders in general opposed the preprint being released to the arXiv server and also opposed the seminars that followed the release of this article and also opposed the press conference. They objected to publication before further tests were carried out to make sure that no systematic errors (that is, errors originating from the experimental system) entered the experiment. Now it seems that those who urged that extra caution should have been taken as well as performing these necessary tests, are the ones who tipped the scales; After all, half of the members of the group oppose the submission for publication of the article, and a new series of tests will indeed be performed before the article is submitted for publication.

The new experiment that will be performed in the coming week will be related to the change of the experimental set-up: the neutrinos beam from CERN will be changed. CERN produces the particles at the SPS Super Proton Synchrotron (the last stage in the production of the energetic protons) by sending bursts of proton pulses that hit a graphite target, while each pulse is 10,500 nanoseconds long. In this way, unstable nutrients are formed that decay into ionized nitrites. Protons travel close to the speed of light, but not at the speed of light. But the neutrinos, whose mass is so tiny, are supposed to move at a speed equal to that of light or very close to it.

Below is an explanation of creation Proton beam at the Large Hadron Collider at: CERN
The researchers first calculated the distribution of protons over time (which created the neutrinos beam). And these correspond to the interactions of the nitrites collected in the OPERA detector. All this in order to get the approximate time when the nitrites were emitted in the range in which they were formed in the SPS.

Below is a detailed explanation:

The goal is to measure the travel time of the neutrinos from CERN to Gran Sasso, assuming that the speed of light is constant. The travel time was measured by the fact that the researchers compared two distributions, the distribution of protons over time - the protons created at CERN, and the distribution of neutrinos over time - the neutrinos discovered at OPERA. When the two distributions exactly match the travel time is obtained. What is the problem with this move?

Let's say that we are performing an ideal experiment and we are not required to calculate the distribution of the many proton pulses on one side and match it to the distribution of the neutrinos pulses on the other side. But instead we measure each and every proton on one side and match it to every neutrino we detect on the other side. Or then the researchers' move would have worked XNUMX percent.

The problem starts when the SPS sends protons in pulses, 1020 protons in each pulse, and these create masses of neutrinos. The nitrites created race across the 730 km distance towards the Gran Sesso laboratory. But only a very small percentage of the neutrinos generated on the CERN side pass by the OPERA detector and are collected by it. It turns out that only about 16,000 neutrinos interacted in OPERA during the three years that the experiment was carried out. And this is a very tiny percentage of the neutrinos that were created on the CERN side. Now we calculate the distribution of protons over time on the CERN side and we calculate the distribution of neutrinos over the time that passed in the OPERA detector on the Gran Sasso side.

The critics argued that it was not really possible to correlate the two distributions, that of the protons produced by CERN and that of the neutrinos that arrived at OPERA. At CERN all protons are included in the measurement. However, by the time the beam reached Gran Sesso, it had already weakened and the OPERA detector is only interacting with some of the neutrinos in the beam. Therefore, a correlation between the time when the neutrinos were created and the time when they actually arrived at OPERA can distort the fit between the two distributions and introduce uncertainty into the calculation of the velocity of the neutrinos.

Repeating the experiment, CERN decided to split the pulses of the protons so that each pulse is divided into pulses of 1 to 2 nanoseconds in length. Between each such pulse there will be an interval of 500 nanoseconds. The change means that it will be possible to connect each neutrino event recorded in the OPERA detector to a specific proton pulse. This will allow a very precise measurement of the travel time of the neutrinos, the time it takes for the neutrinos to travel between the two laboratories, CERN and Gran Sasso. Still the critics are not satisfied and suspect that this measurement may not be reliable...
Sources suggest the group perform the measurements over a few days only, probably starting next week, during which time it may intercept about 12 neutrinos in OPERA. It is possible that by doing this the group will generate enough data to either disprove or verify the bulk of what is behind their result.

In the meantime, a number of tests are being carried out following several articles that have been uploaded to the arXiv server by other physicists as a response to the first experiment in question. Some have suggested the theoretical implications of neutrinos moving at superluminal speeds and some have argued that the result must be wrong for some reason. As I recall, one oral article was by Andrew Cohen and Sheldon Glasho from Boston University. The ICARUS detector team tried to check the OPERA result based on Cohen's article and looked at the data collected in the ICARUS detector since 2010. The ICARUS detector does not directly measure the velocity of neutrinos, but instead the spectral energy of the neutrinos beam that travels from CERN to Gran Sasso. The ICARUS team found that although the effect described by Cohen and Galusho - and they expected that in the OPERA experiment they would discover it to the extent that the neutrinos move quickly on Orit - does not occur in the CERN neutrino beam for OPERA. OPERA did not see this effect and Cohen and Galusho's claim was that the neutrinos therefore do not move quickly On Orit. The ICARUS team explained: such an effect does not exist, therefore OPERA did not observe it.

The ICARUS experiment:

For information on the subject in Nature