Sterile neutrino and the early universe?

In summary, the presence of sterile neutrinos in the early universe and during the neutrino decoupling era has various effects that depend on their mass and mixing with active neutrinos. The interpretation of these effects also varies depending on the epoch being considered. The existence of sterile neutrinos is still uncertain and their properties, such as right-handedness, are still being studied. However, it is believed that if sterile neutrinos do exist, they would likely only have right-handed chirality.
  • #1
kimmm
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What are the effects considered by the presence of sterile neutrinos and the early universe, and the neutrino decoupling era?
 
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  • #2
Is your question what types of early universe effects you need to consider if there are additional sterile neutrinos?

The answer to that question depends on its mass and mixing with the active neutrinos as well as what epoch of the early universe you are considering. Can you be more specific in your question?
 
  • #3
Orodruin said:
Is your question what types of early universe effects you need to consider if there are additional sterile neutrinos?

The answer to that question depends on its mass and mixing with the active neutrinos as well as what epoch of the early universe you are considering. Can you be more specific in your question?
So the thing I understand form your respond, you mean for any epoch of early universe there is a special kind of interpreration for the existence of sterile neutrinos?
for example if we consider the neutrino decoupling epoch, how we can explain them, and actually does it depend on the mass of we consider for the sterile neutrinos, as we do not know the mass, by the results of experiments they put bounds on that, and specially consider it 1eV^2?

And I have another question, since we talk about sterile neutrinos, we consider them just as a particle with right-handed chirality, not like other kind of particles both handed chirality?
thanks in advanced.
 
  • #4
kimmm said:
So the thing I understand form your respond, you mean for any epoch of early universe there is a special kind of interpreration for the existence of sterile neutrinos?
No, I mean that depending on the mass and mixing of the sterile neutrino it will have very different consequences that are relevant at different times.

kimmm said:
for example if we consider the neutrino decoupling epoch, how we can explain them, and actually does it depend on the mass of we consider for the sterile neutrinos, as we do not know the mass, by the results of experiments they put bounds on that, and specially consider it 1eV^2?
First of all, 1 eV^2 cannot be a mass, it is a mass squared. It also makes me think that you are thinking of the sterile neutrino interpretation of the LSND and MiniBooNE experiments. Such a sterile neutrino would be in conflict with standard cosmology and it is doubtful that it is the correct interpretation of the LSND and MiniBooNE results. We recently had a featured thread discussing this in connection to the latest release of MiniBooNE data.

kimmm said:
And I have another question, since we talk about sterile neutrinos, we consider them just as a particle with right-handed chirality, not like other kind of particles both handed chirality?
Normal neutrinos only have one chirality that we are aware of. Adding a right-handed neutrino to explain masses like for all other particles (via the Yukawa coupling to the Higgs), that right-handed neutrino would be sterile.
 
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  • #5
Orodruin said:
Normal neutrinos only have one chirality that we are aware of. Adding a right-handed neutrino to explain masses like for all other particles (via the Yukawa coupling to the Higgs), that right-handed neutrino would be sterile.

Is it correct to say, being right-handed is one of the properties of sterile neutrinos, or there may exist both right- and left- handed sterile neutrinos?
 

Related to Sterile neutrino and the early universe?

1. What is a sterile neutrino and how does it relate to the early universe?

A sterile neutrino is a hypothetical particle that does not interact with other particles via the weak nuclear force. It is believed to have a mass much higher than that of the other known neutrinos. In the early universe, sterile neutrinos may have played a role in the creation of matter and anti-matter imbalances.

2. How is the existence of sterile neutrinos supported by scientific evidence?

The existence of sterile neutrinos is currently supported by several experiments, including the LSND, MiniBooNE, and Daya Bay experiments, which have observed anomalies in the behavior of neutrinos that cannot be explained by the known types of neutrinos. Additionally, the presence of sterile neutrinos would help to explain the observed matter-antimatter asymmetry in the universe.

3. What role do sterile neutrinos play in the process of neutrino oscillation?

Neutrino oscillation is the phenomenon in which neutrinos can change from one type to another as they travel through space. Sterile neutrinos are believed to be involved in this process, as they can mix with the known types of neutrinos and cause them to change flavor. This has been observed in experiments such as the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE.

4. How do sterile neutrinos affect the formation and evolution of galaxies and other cosmic structures?

Sterile neutrinos have been proposed as a potential explanation for the observed "missing mass" in the universe, also known as dark matter. If they exist, they would have played a role in the early stages of galaxy formation and continue to influence the distribution of matter in the universe.

5. What are the current theories and research surrounding the properties and behavior of sterile neutrinos?

There are several theories and ongoing research efforts surrounding sterile neutrinos, including their potential role in dark matter, their effects on the cosmic microwave background, and their interactions with other particles. There are also ongoing experiments, such as the upcoming Short-Baseline Neutrino Program, that aim to further investigate the properties of sterile neutrinos and their potential impact on our understanding of the early universe.

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