1
$\begingroup$

In Leptogenesis, CP-asymetry arises due to the interference of the tree-level amplitude $N\rightarrow l_\alpha\phi$ (where $N$ is heavy sterile neutrino, $l_\alpha$ is a lepton flavour, and $\phi$ is the Higgs) with the higher order amplitudes (say, one-loop amplitude).

This was a decay. Let us consider an scattering so that there may me more than one diagrams at the tree level. For a given scattering $A+B\rightarrow C+D$, there may be two tree-level diagrams. Similarly for the process $\bar{A}+\bar{B}\rightarrow \bar{C}+\bar{D}$ where will be two again. Can we have CP-asymetry due to the interference between two different tree-level scattering amplitudes?

I believe the question makes sense. If not I shall try to clarify it further.

$\endgroup$
0
$\begingroup$

Generating CP asymmetry from scattering process is indeed possible. Actually, already in leptogenesis people have considered such processes because they dominate at high energy ($T>M_N$) but it turns out that they have negligible effects on the final asymmetry (e.g., hep-ph/0309342).

A field $\psi$, which has CP violating interactions with fermions $f$, can lead to different rates for the processes $\psi\psi\to \bar f$ and $\overline{\psi\psi}\to f$ provided departure from thermal (c.f. 1407.4566 and refs therein).

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.