ah ok. So we know the universe is neutral, therefore we know we have more charged leptons (negative) in the form of electrons than we do charged antileptons (positive). So we must have a charged lepton asymmetry.
But since neutrinos are neutral, and we have not yet measured the relic neutrino...
Thank you very much for the replies.
You mention deltaCP has no limit and that it could be large - sure, and for neutrino oscillation physics this is a big focus. Some experiments have started to rule out certain values with at least 2 sigma, and one of the big selling points of obtaining...
Thanks for the reply. I am being a bit slow here, but I still don't understand, could you please give me an example of an interaction that creates a lepton excess?
Are you suggesting a negative baryon decays somehow to give an electron??I would have guessed a lepton asym would need the same...
Ah ok. Right. Thanks for the reply. So I'll go back to my original way of thinking, only 1/3 of antileptons are converted.
The sphaleron interactions reach chemical equilibrium as 1/3 of the antilepton excess is converted to baryons.
So at the end of leptogenesis, you are left with an...
I have a slightly related question (although I guess its more general in the sense it could apply to any particles before EWSB)
Before EWSB the neutrinos do not have mass. But to thermally produce the heavy neutrinos, we consider the temperature of the universe relative to the mass (which is...
Hello
In sphaleron interactions (B - L) is conserved.
So we need an antilepton excess (provided by decay of heavy RH neutrinos in leptogenesis).
This is then converted to a baryon excess, via sphalerons, to explain the baryon excess that we observe.
But the conversion factor is ~1/3.
For...
ahhhh, ok yes, so when i swap the round the ## m_D ## and ## m_D^T## I then get ## m_{\nu} ## which is the same in the two conventions, so i just diagonlise the same and carry on from there. Ok great. Thanks for the help, sorry this was more drawn out than it probably needed to be!
So when I say they have real values, I meant because you chose to do a rephasing of the fields such that you decide ## m_D ## and ## D_M ## are real. (and you let ## m_L ## stay complex but you set this to zero anyway ).
But yes, sorry, I should be careful as this is a convention which may not...
Hello, thanks for the reply.
All the terms in A and B are matrices with real values.
the right hand side of A is the hermitian conjugate of B
so I think it comes from in the lagranian and the hermitian conjugate L = mass_term + h.c.
So if you work with 'mass_term' and rearrange to find...
ok so this is a bit of a boring question, so sorry in advance, but for some reason I am struggling with this.
I am deriving the seesaw formula.
Now I have gone through the derivivate and I get A : ## m_{\nu} = - m_D^T M^{-1} m_D ##
Now I have seen other derivations where they get B ...
Sorry I thought about it some more and I'm still a bit confused.
If the prime and non-prime are different basis, why do they keep the flavour index in both?
##\nu'_{e L} = A\nu_{eL} + B\nu_{\mu L} + C\nu_{\tau L} ##
-> which looks weird... e is a flavour state on the right ... why would you...
Oh, ok, well I guess that's simple enough then!
I was reading the 'Fundamentals of neutrino physics and astrophysics' book, seesaw chapter, and always they start everything with primed basis then convert to un-primed so I thought it must have some meaning, then I looked in earlier chapters and...
To determine the mass of charged leptons, we rotate such that the matrix of yukawa couplings (which gives the mass matrix after EWSB) is diagonal.
We also call this flavour basis for neutrinos, because the flavoured neutrinos couple directly to the correspondong flavoured lepton in weak charged...