Neutrino Oscillations and Mass

In summary, neutrino oscillations would not occur if all three standard model neutrinos had the same mass, as the oscillation parameters depend on the differences between the squared masses. It is expected that all three mass eigenstates have a non-zero mass, but currently we are sure only for two of them. However, it is possible for one mass eigenstate to be massless, as seen in some models such as type I seesaw with only two righthanded neutrinos. The assumption of all three mass eigenstates having rest frames may not be necessary for deriving neutrino oscillations.
  • #1
Trixie Mattel
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Hello

Just wondering, would neutrino oscillations occur is the three standard model neutrinos were the same mass?

or are different masses needed in order to have different phases differences, as the phases differences are why the oscillations occur?Also why do neutrino oscillations prove that neutrinos are not massless. Is it because the weak eigenstates are a linear superposition of mass eigenstates?Thank you
 
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  • #2
Trixie Mattel said:
Just wondering, would neutrino oscillations occur is the three standard model neutrinos were the same mass?
If all three mass eigenstates have the same mass, there are no oscillations. The oscillation parameters depend on the differences between the squared masses. You have to have non-zero differences for oscillations.

One mass eigenstate could be massless, but that would be odd - it is expected that all three mass eigenstates have a non-zero mass, but currently we are sure only for two of them.
 
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  • #3
mfb said:
One mass eigenstate could be massless

Can it? I think the standard derivation assumes that all three mass eigenstates have rest frames. There may be some other way to approach it without this assumption.
 
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  • #4
As far as I know it is no problem to have one mass at exactly zero instead of a very small mass. @Orodruin knows it for sure.
 
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  • #5
It is perfectly fine to have one massless neutrino. It occurs in some (admittedly odd) models, eg, type I seesaw with only two righthanded neutrinos.
 
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A number of problematic and/or off topic posts and responses have been deleted. Thread re-opened.
 
Last edited:

1. What are neutrino oscillations and why are they important?

Neutrino oscillations refer to the phenomenon in which neutrinos change from one type (flavor) to another as they travel through space. This is important because it provides evidence that neutrinos have mass, which was previously thought to be massless according to the Standard Model of particle physics.

2. How do neutrinos change flavor during oscillations?

Neutrinos have three different flavors: electron, muon, and tau. During oscillations, a neutrino of one flavor can change into a neutrino of a different flavor. This is possible because neutrinos have a small amount of mass, allowing them to interact with each other and change flavors.

3. What is the role of neutrino mass in oscillations?

The mass of a neutrino determines how quickly it can change flavors during oscillations. The greater the mass, the slower the oscillation rate. This is due to the fact that higher mass neutrinos have a shorter wavelength, making it more difficult for them to interact and change flavors.

4. How do scientists study neutrino oscillations and mass?

Scientists use various experiments, such as the Super-Kamiokande and IceCube detectors, to study neutrino oscillations and mass. These experiments involve observing the different flavors of neutrinos and measuring the changes in their oscillation patterns over time.

5. What implications do neutrino oscillations and mass have for our understanding of the universe?

Neutrino oscillations and mass have significant implications for our understanding of the universe. They provide evidence for the existence of dark matter and may help explain the matter-antimatter asymmetry in the universe. Additionally, they could potentially lead to the discovery of new physics beyond the Standard Model.

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