Prospects for measuring the gravitational free-fall of antihydrogen with emulsion detectors

TL;DR

This paper evaluates the use of emulsion detectors in measuring the gravitational free-fall of antihydrogen at CERN, aiming to test the weak equivalence principle with high precision.

Contribution

It demonstrates the feasibility of using emulsion detectors operated in vacuum for precise vertex measurements in antihydrogen experiments.

Findings

Emulsion detectors achieved 1-2 micron vertex resolution.

Results align with Monte Carlo simulations.

Implications for improving gravitational acceleration measurements.

Abstract

The main goal of the AEgIS experiment at CERN is to test the weak equivalence principle for antimatter. AEgIS will measure the free-fall of an antihydrogen beam traversing a moir\'e deflectometer. The goal is to determine the gravitational acceleration g for antihydrogen with an initial relative accuracy of 1% by using an emulsion detector combined with a silicon micro-strip detector to measure the time of flight. Nuclear emulsions can measure the annihilation vertex of antihydrogen atoms with a precision of about 1 - 2 microns r.m.s. We present here results for emulsion detectors operated in vacuum using low energy antiprotons from the CERN antiproton decelerator. We compare with Monte Carlo simulations, and discuss the impact on the AEgIS project.