Sterile neutrino and the early universe?

[kimmm]

What are the effects considered by the presence of sterile neutrinos and the early universe, and the neutrino decoupling era?

 

[Orodruin]

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?

 

[kimmm]

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.

 

[Orodruin]

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.

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.

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.

 

[kimmm]

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?