Tachyonic Neutrinos

[elas]

this will not mean a rewrite of physics.

 

it means there will need to be a theory to replace relativity(both special and general) but it will replace relativity in the same way general relativity replaced newtonian gravity.

 

In most cases, the new theory would reduce to relativity.

 

Precisely, the key observation is that neutrinos created outside a magnetic ring travel at close to the speed of light; neutrinos created within a magnetic ring travel faster than the speed of light (on exiting). The cause is that actions within a magnetic ring occur in a different (i.e. non-universal) time frame where c in the universal time frame becomes '0' in the internal time frame of the magnetic ring. The momentum generated within the ring continues when the neutrinos leave the ring and enter the universal time frame. All that is needed is an extension to relativity that takes into account non-universal time frames.

Edited October 20, 2011 by elas

[Enthalpy]

The experiment has been improved using short pulses of about 3ns:

http://arxiv.org/abs/1109.4897

and gives the same result, which removes many interrogations about the setup, including mines about dispersion in the current transformer and the transmission line.

 

Next step shall add a muon detector at the source, to obtain a more direct measure of the start time (remember the chain is proton -> muon -> neutrino).

 

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Apparently, the experiment now takes short pulses with slow (500ns) repetition rate, maybe to avoid aliasing between the pulses.

 

Signal processing techniques from radar and sonar, like frequency chirp or pseudo-random sequences or spread spectrum would still prevent confusion between the pulses but allow closely spaced pulses. For instance 50 times more pulses in the same duration would shorten the measurement campaign 50 times provided the modulator achieves it.

 

Marc Schaefer, aka Enthalpy

[Cap'n Refsmmat]

How would you detect a frequency chirp in a neutrino detection? Neutrinos are very difficult to detect, so out of many pulses you may only detect one neutrino. With only one neutrino, you can't reconstruct any clever pulses.

[imatfaal]

How would you detect a frequency chirp in a neutrino detection? Neutrinos are very difficult to detect, so out of many pulses you may only detect one neutrino. With only one neutrino, you can't reconstruct any clever pulses.

 

You use the same profile chirp (proton pulse) to create your neutrinos every run - over tens of thousands of chirps you plot the number of signals received against time delay of receipt, if you have done it correctly the profile of your chirp is recreated in the distribution of individual signals received. to an extent the first Gran Sasso results did this to an extent - the time distribution profile of neutrinos detected matched the profile of the (two different) proton pulses creating cascades which lead to neutrinos.

[Enthalpy]

Yes, that's it.

 

Over two weeks, 3ns pulses separated by 500ns allowed to accumulate some 15 neutrino detections.

(remember the original experiment detects the mu to tau neutrino oscillation. It's less difficult to detect the produced mu neutrinos in the flight time experiment)

 

Their proton beam is modulated at 5ns, so if the modulator permits it, a pseudo-random sequence that keeps nearly 50% of all pulses would emit 50 pulses in 500ns, not just one. Over the same time, they would detect 750 neutrinos instead of 15, improving accuracy or waiting time.

 

Now, if one wants to imagine what happens during the mathematical de-convolution, it's not very intuitive...

People with a background for signal processing need several hours to get a usable mental image of it.

But pulse compression does work in countless uses, including cell phones, and with a few particle detections as well as with a noisy signal.

 

Imagine the experimenters want to keep two weeks integration:

they get 750 detections within 40ns or 8 time bins, giving almost 100 neutrinos per bin.

The mathematical pulse compression operation will produce noise in the wrong time bins, but this noise accumulates as sqrt(100)=10.

(This is because, in a sequence composed of +1 and -1, a detected particle sometime adds, sometimes subtract, at the wrong bins)

In the proper time bins, the signal accumulates as 100, giving 10 sigma signal-to-noise. Better than 1 event per bin as of today.

This permits to interpolate the flight time to less than one time bin, and compare the distribution with the one expected from detector behaviour.

 

Radar and sonar do this for the same reason the neutrino experiment should:

they want to transmit a limited power over a longer time to increase the pulse energy, but keep time accuracy.

[Tres Juicy]

Sorry about the offtopic but this is a good one:

 

 

Bartender says: "We don't serve neutrinos here."

 

A neutrino walks into a bar.

 

 

 

A neutron walks into a bar and says "how much for a drink?"

 

Bartender says "for you? - No charge"

Edited December 8, 2011 by Tres Juicy