Can neutrinos undergo elastic backscatter collisions and what happens to their spin?

[snorkack]

Can a neutrino undergo elastic collision with a particle participating in weak interaction, such as an electron, a nucleon, or other lepton or a hadron, such that the direction of neutrino movement changes by 180 degrees?

If yes, what is the direction of the neutrino spin relative to its direction of movement before and after the collision?
What is the direction of neutrino spin relative to outside frame of reference before and after collision?

Can a neutrino be reflected by a pi meson, seeing that the pi meson has no spin and therefore cannot change it?

 

[Vanadium 50]

Can a neutrino undergo elastic collision with a particle participating in weak interaction, such as an electron, a nucleon, or other lepton or a hadron

Yes

such that the direction of neutrino movement changes by 180 degrees?

No. The probability for exactly 180 degrees is zero. The probability for around 180 is very low. This is just Rutherford scattering.

What is the direction of neutrino spin relative to outside frame of reference before and after collision?

It sounds like you are getting confused with helicity and chirality. The helicity of the neutrino doesn't matter when determining what the interactions are. That's the chirality.

 

[snorkack]

It sounds like you are getting confused with helicity and chirality. The helicity of the neutrino doesn't matter when determining what the interactions are. That's the chirality.

So what exactly is the spin constraint on neutrinos, which is not shared by e. g. an electron scattering under electromagnetic interaction?

 

[Vanadium 50]

Active neutrinos have left-handed chirality.

 

[snorkack]

Active neutrinos have left-handed chirality.

So in which frame does neutrino spin have to be left-handed?

 

[Vanadium 50]

Chirality is frame independent.

 

[snorkack]

Then do other massive particles possesses frame independent chirality?

 

[Vanadium 50]

Chirality is frame independent. Not "chirality for neutrinos". Just plain old chirality.

 

[snorkack]

Then which interactions are right chiral neutrons capable of?

 

[Vanadium 50]

None. They're sterile.

 

[snorkack]

Are right chiral neutrons and protons then also incapable of strong interaction?

 

[mfb]

No, this chirality-dependence is a unique feature of the weak interaction.

 

[snorkack]

Then would a right chiral neutron be able to be included in nuclei (under strong interaction) but barred from weak interaction... and therefore beta decay?

 

[mfb]

The W couples to the quarks, not to the neutron.

 

[Vanadium 50]

Snorkack, it feels like you are playing 20 questions with us. What is it that you are trying to figure out?

And there is no such thing as a "right chiral neutron". With questions like this, I get the feeling you don't understand either helicity or chirality. If that's the case, reading up on them is probably more helpful than asking questions intended to illuminate the difference. It's like trying to explain the difference between an orange and a tangerine to someone struggling with the concept of "fruit".

 

[snorkack]

Does chirality place any spin constraints on neutrino? If yes, which ones?