# Sterile Neutrino. A short introduction

## TL;DR

This pedagogical paper introduces sterile neutrinos, discussing their theoretical motivation, potential observational signatures, and current experimental searches, highlighting their significance in resolving neutrino anomalies.

## Contribution

It provides a comprehensive overview of sterile neutrino concepts, anomalies, and detection methods, emphasizing the importance of coherence effects in oscillation models.

## Key findings

- Sterile neutrinos could explain existing neutrino anomalies.
- Loss of coherence may significantly impact oscillation interpretations.
- Current searches have yet to confirm sterile neutrino existence.

## Abstract

This is a pedagogical introduction to the main concepts of the sterile neutrino - a hypothetical particle, coined to resolve some anomalies in neutrino data and retain consistency with observed widths of the $W$ and $Z$ bosons. We briefly review existing anomalies and the oscillation parameters that best describe these data. We discuss in more detail how sterile neutrino can be observed, as well as the consequences of its possible existence. In particular, we pay attention to a possible loss of coherence in a model of neutrino oscillations with sterile neutrinos, where this effect might be of a major importance with respect to the 3$\nu$ model. The current status of searches for a sterile neutrino state is also briefly reviewed.