AEg̅IS latest results

F Guatieri,G Nebbia,A Hinterberger,P Lebrun,L Di Noto,V Lagomarsino,N Pacifico,D Krasnický,H Holmestad,Z Mazzotta,P Lansonneur,J Fesel,F Prelz,M Fanì,G Testera,A Demetrio,S Haider,P Yzombard,C Amsler,R Caravita,G Consolati,S Gerber,G Bonomi,N Zurlo,L Smestad,A Fontana,A Gligorova,Simon Müller ,P Nédélec ,I C Tietje ,Christian Zimmer ,O Rhne ,M C Simon ,B Rienäcker ,R S Brusa ,Markus K Oberthaler ,V Petráček ,J Robert,L Penasa,S Aghion,M Sacerdoti,V Matveev,R Ferragut,C Malbrunot,M Giammarchi,M Doser,G Angela,A Rotondi,H Sandaker,A Kellerbauer,D Comparat,G Cerchiari,J Zmeskal,S Mariazzi,F Castelli,R Santoro,E Widmann,D Pagano,M Prevedelli,F Sorrentino,M Caccia,C Evans

doi:10.1051/epjconf/201718101037

Abstract

The validity of the Weak Equivalence Principle (WEP) as predicted by General Relativity has been tested up to astounding precision using ordinary matter. The lack hitherto of a stable source of a probe being at the same time electrically neutral, cold and stable enough to be measured has prevented highaccuracy testing of the WEP on anti-matter. The AEg̅IS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment located at CERN's AD (Antiproton Decelerator) facility aims at producing such a probe in the form of a pulsed beam of cold anti-hydrogen, and at measuring by means of a moiré deflectometer the gravitational force that Earth's mass exerts on it. Low temperature and abundance of the H̅ are paramount to attain a high precision measurement. A technique employing a charge-exchange reaction between antiprotons coming from the AD and excited positronium atoms is being developed at AEg̅IS and will be presented hereafter, alongside an overview of the experimental apparatus and the current status of the experiment

Highlights

Despite strong and electroweak matter-antimatter interactions being widely studied in the last 85 years, as of today nobody has been able to observe antimatter interact through gravity
To meet its demand of pulsed cold H, AEg IS employs the charge exchange production scheme shown in figure 2; it consists in having an antiproton react with a Rydberg excited positronium, producing an antihydrogen and freeing the electron as a result
We were able to employ the secondary positron chamber and the laser apparatus to produce and detect n = 3 states of positronium[14] by comparing the area under the Single Shot Positron Annihilation Lifetime Spectroscopy (SSPALS) spectrum in a region adjacent to the main prompt peak when the UV laser was shone onto the positronium cloud and when both the UV and the Ionization laser where shone onto it

Summary

Introduction

Despite strong and electroweak matter-antimatter interactions being widely studied in the last 85 years, as of today nobody has been able to observe antimatter interact through gravity. Gravitational pull will be measured directly by letting an uncollimated beam of cold antihydrogen travel through a moiré deflectometer[3] as shown in figure 1. Both the time of flight ∆t through the full deflectometer and the vertical displacement ∆t to which the particles were subject will need to be measured. To meet its demand of pulsed cold H , AEg IS employs the charge exchange production scheme shown in figure 2; it consists in having an antiproton react with a Rydberg excited positronium, producing an antihydrogen and freeing the electron as a result. When the cloud of excited positronium intersects the pcloud inside of the production trap the charge exchange reaction takes place and anithydrogen is produced which will be extracted by means of stark acceleration from the production trap and conveyed onto the deflectometer to perform the actual measurement

Commissioning of the positronium line