# Fundamental Physics with High-Energy Cosmic Neutrinos

## TL;DR

High-energy cosmic neutrinos offer a unique window into fundamental physics, enabling tests of new particles and interactions at scales unreachable by current laboratories through detailed measurements of their properties.

## Contribution

This white paper outlines the potential of high-energy cosmic neutrinos to address key particle physics questions and guides future experimental efforts.

## Key findings

- Neutrino observations can probe physics beyond the Standard Model.
- Energy spectrum and flavor measurements are crucial for new physics searches.
- Cosmic neutrinos can test fundamental interactions at extreme energies.

## Abstract

High-energy cosmic neutrinos can reveal new fundamental particles and interactions, probing energy and distance scales far exceeding those accessible in the laboratory. This white paper describes the outstanding particle physics questions that high-energy cosmic neutrinos can address in the coming decade. A companion white paper discusses how the observation of cosmic neutrinos can address open questions in astrophysics. Tests of fundamental physics using high-energy cosmic neutrinos will be enabled by detailed measurements of their energy spectrum, arrival directions, flavor composition, and timing.