Nutrino Mass and Oscillation problem

In summary: However, the energy is so high that the atmospheric neutrino background is very low.In summary, the conversation discusses the speed of neutrinos and their potential for oscillation between different flavors. While it is generally accepted that neutrinos do have mass and travel slightly below the speed of light, some theories suggest the possibility of them traveling at or above the speed of light. However, current experiments do not have the sensitivity to accurately measure the speed of neutrinos. The conversation also briefly touches on the topic of whether gamma ray flashes emit neutrinos, with the conclusion that if they do, they are likely to be at a very high energy level and difficult to detect.
  • #1
FeynmanIsCool
121
0
I have a question:

Excuse me if this has been answered on here. Neutrino's are said to travel at the speed of light. As we know anything with mass cannot travel at c. We have also observed neutrino "influxes" at the same time we observe a super nova, which means that neutrino's and photons are traveling at the same speed.

BUT

What about Neutrino oscillations? Neutrino's are said to change from electron neutrino --> tau neutrino --> muon neutrino, and so on. In order for these oscillations to happen, the neutrino must experience time, because these oscillations are time dependent. But we also know due to Relativity that time stops when you travel at c. If time was "stopped" for a neutrino, how can it oscillate?
Has this dilemma been answered already, and I have not done enough research?
Thanks in advance!
 
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  • #2
Neutrino's are said to travel at the speed of light.
Where?
"Close to the speed of light" is not "at the speed of light".

We have also observed neutrino "influxes" at the same time we observe a super nova, which means that neutrino's and photons are traveling at the same speed.
Nearly the same, which is a completely different statement. The difference is too small to observe it with current experiments.
 
  • #3
"In the early 1980s, first measurements of neutrino speed were done using pulsed pion beams (produced by pulsed proton beams hitting a target). The pions decayed producing neutrinos, and the neutrino interactions observed within a time window in a detector at a distance were consistent with the speed of light. This measurement was repeated in 2007 using the MINOS detectors, which found the speed of 3 GeV neutrinos to be 1.000051(29) c at 68% confidence level, and at 99% confidence level a range between 0.999976 c to 1.000126 c. The central value is higher than the speed of light and is consistent with superluminal velocity; however, the uncertainty is great enough that the result also does not rule out speeds less than or equal to light at this high confidence level" -wiki on neutrinos

so what is the speed?? is it close to light or what?
 
  • #4
mfb said:
Where?
"Close to the speed of light" is not "at the speed of light".


Nearly the same, which is a completely different statement. The difference is too small to observe it with current experiments.

"The same observation was made, on a somewhat larger scale, with supernova 1987A (SN 1987A). 10-MeV antineutrinos from the supernova were detected within a time window that was consistent with a speed of light for the neutrinos. So far, the question of neutrino masses cannot be decided based on measurements of the neutrino speed." - wiki on neutrinos
 
  • #5
Im not paying any attention to claims that neutrinos can travel faster than C, I know all those claims are miss calculations, and have since been proven wrong, so you don't need to bring that up.
 
  • #6
With neutrino masses of the order of some milli-electron volt and neutrino energies of some MeV, the neutrino speed is about c*(1-10-18) or 0.999999999999999999 c.

SN1987 A was about 150,000 light years away, the sub-luminal speed corresponds to a time difference of the order of some microseconds.
No experiment has the sensitivity to see that small deviation from c, even if the deviation is crucial for mixing.
 
  • #7
ok, thanks! So basically, it comes down to: We know that neutrino's don't travel at c, but our experiments don't have the sensitivity to tell how close to c neutrino's are traveling...slightly un-settling
 
  • #8
I believe the general consensus at this point is that neutrinos do have mass. They are almost massless, and travel at a velocity very near C. But as you mentioned, the fact that they oscillate between flavors implies V<C. Although this is the generally accepted stance, there are apparently types of Lorentz-violations in some quantum gravity theories that could allow for neutrino velocity at or above C. My understanding (someone correct me if I'm wrong), is that they aren't very viable at this point (in the sense of being testable/falsifiable), but you might find them interesting nonetheless: http://en.wikipedia.org/wiki/Lorentz-violating_neutrino_oscillations#General_predictions
 
  • #9
FeynmanIsCool said:
ok, thanks! So basically, it comes down to: We know that neutrino's don't travel at c, but our experiments don't have the sensitivity to tell how close to c neutrino's are traveling...slightly un-settling
Right.
And without a method to produce collimated low-energy neutrinos or without very distant supernovae, I don't expect changes in that respect.

Direct mass measurements (beta decay) could measure the electron neutrino mass, and mixing experiments can give mass differences.
 
  • #10
So, do gamma ray flashes emit neutrinos?
 
  • #11
snorkack said:
So, do gamma ray flashes emit neutrinos?

http://arxiv.org/abs/0907.2227
In none of the three time windows do we find a deviation from the background-only hypothesis.

The bad news: If there are neutrinos, they are even more high-energetic, and they can be produced at a different time.
 

1. What is the Nutrino Mass and Oscillation problem?

The Nutrino Mass and Oscillation problem refers to the observed phenomenon of nutrinos, which are subatomic particles with very little or no mass, changing from one type to another as they travel through space. This is known as nutrino oscillation and it challenges our understanding of the Standard Model of particle physics.

2. How do nutrinos change from one type to another?

Nutrinos have three different types or flavors: electron, muon, and tau. According to the Standard Model, they should maintain a specific type as they travel, but studies have shown that nutrinos can change from one type to another due to quantum mechanical effects.

3. Why is the Nutrino Mass and Oscillation problem important?

The Nutrino Mass and Oscillation problem is important because it challenges our current understanding of the fundamental particles and forces that make up our universe. It also has implications for cosmology, as the behavior of nutrinos could have played a role in the evolution of the universe.

4. How do scientists study nutrino oscillation?

Scientists study nutrino oscillation by observing the interactions of nutrinos in large detectors, such as the Super-Kamiokande and IceCube experiments. They also use powerful particle accelerators, such as the Large Hadron Collider, to produce and study nutrinos.

5. What is the current status of the Nutrino Mass and Oscillation problem?

While there is still much to learn about nutrino oscillation, significant progress has been made in recent years. Scientists have observed and measured nutrino oscillation, providing evidence for the existence of nutrino mass. However, there are still unanswered questions and ongoing research in this field.

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