Flavor effects in leptogenesis

TL;DR

This paper reviews how flavor effects influence leptogenesis, emphasizing the importance of detailed flavor dynamics in accurately estimating matter-antimatter asymmetry and exploring their impact across various models.

Contribution

It provides a comprehensive overview of flavor effects in leptogenesis, including regimes of relevance, their impact on models, and methods to incorporate these effects accurately.

Findings

Flavor effects can significantly alter leptogenesis predictions.

Different models show varied sensitivity to flavor dynamics.

Methods to incorporate flavor effects include semi-classical and field-theoretic approaches.

Abstract

Flavor effects can have a significant impact on the final estimate of the lepton (and therefore baryon) asymmetry in scenarios of leptogenesis. It is therefore necessary to account fully for this flavor dynamics in the relevant transport equations that describe the production (and washout) of the asymmetry. Doing so can both open up and restrict viable regions of parameter space relative to the predictions of more approximate calculations. In this review, we identify the regimes in which flavor effects can be relevant and illustrate their impact in a number of phenomenological models. These include type I and type II seesaw embeddings, and low-scale resonant scenarios. In addition, we provide an overview of the semi-classical and field-theoretic methods that have been developed to capture flavor effects in a consistent way.