Neutrino physics with the PTOLEMY project: active neutrino properties and the light sterile case

TL;DR

The PTOLEMY project aims to develop a detector capable of directly observing the Cosmic Neutrino Background, exploring neutrino mass properties, and investigating light sterile neutrinos through beta decay spectrum analysis.

Contribution

This paper provides a detailed theoretical framework for PTOLEMY, assessing its sensitivity to neutrino mass scales and sterile neutrino properties, advancing neutrino detection methods.

Findings

PTOLEMY can potentially detect the CNB with sufficient energy resolution.

The experiment's sensitivity to active neutrino mass scale is evaluated.

Sterile neutrino effects could be observed via distortions in the beta decay spectrum.

Abstract

The PTOLEMY project aims to develop a scalable design for a Cosmic Neutrino Background (CNB) detector, the first of its kind and the only one conceived that can look directly at the image of the Universe encoded in neutrino background produced in the first second after the Big Bang. The scope of the work for the next three years is to complete the conceptual design of this detector and to validate with direct measurements that the non-neutrino backgrounds are below the expected cosmological signal. In this paper we discuss in details the theoretical aspects of the experiment and its physics goals. In particular, we mainly address three issues. First we discuss the sensitivity of PTOLEMY to the standard neutrino mass scale. We then study the perspectives of the experiment to detect the CNB via neutrino capture on tritium as a function of the neutrino mass scale and the energy resolution of the apparatus. Finally, we consider an extra sterile neutrino with mass in the eV range, coupled to the active states via oscillations, which has been advocated in view of neutrino oscillation anomalies. This extra state would contribute to the tritium decay spectrum, and its properties, mass and mixing angle, could be studied by analyzing the features in the beta decay electron spectrum.