Introduction to direct neutrino mass measurements and KATRIN

TL;DR

This paper introduces KATRIN, a leading experiment designed to measure the neutrino rest mass with high precision by analyzing beta decay electrons near their endpoint, contributing significantly to understanding neutrino properties.

Contribution

It presents the design, capabilities, and current status of the KATRIN experiment, a novel and advanced approach to directly measure neutrino mass in a model-independent way.

Findings

KATRIN aims for 0.2 eV/c sensitivity at 90% C.L.

It uses an ultra-luminous gaseous tritium source and MAC-E filter spectrometer.

The experiment is in the advanced commissioning stage.

Abstract

The properties of neutrinos and especially their rest mass play an important role at the intersections of cosmology, particle physics and astroparticle physics. At present there are two complementary approaches to address this topic in laboratory experiments. The search for neutrinoless double beta decay probes whether neutrinos are Majorana particles and determines an effective neutrino mass value. On the other hand experiments such as MARE, KATRIN and the recently proposed Project 8 will investigate the spectral shape of beta-decay electrons close to their kinematic endpoint in order to determine the neutrino rest mass with a model-independent method. Here, because of neutrino flavour mixing, the neutrino mass appears as an average of all neutrino mass eigenstates contributing to the electron neutrino. The KArlsruhe TRItium Neutrino experiment (KATRIN) is currently the experiment in the most advanced status of commissioning. It combines an ultra-luminous molecular windowless gaseous tritium source with an integrating high-resolution spectrometer of MAC-E filter type. It will investigate the neutrino rest mass with 0.2 eV/c (90% C.L.) sensitivity and allow beta spectroscopy close to the tritium endpoint at 18.6 keV with unprecedented precision.