Testing the Weak Equivalence Principle with an antimatter beam at CERN

Mitsuhiro Kimura ,F Castelli ,A Demetrio ,A Ariga ,P Nédélec ,H Sandaker ,N Pacifico ,Markus K Oberthaler ,D Comparat ,J W Storey ,G Cerchiari ,А С Белов ,S Gerber ,A Ereditato ,E Widmann ,A Fontana ,S Aghion ,A Kellerbauer ,V Petráček ,R Caravita ,S Rosenberger ,L Di Noto ,T Huse ,H Holmestad ,F Sorrentino ,L Ravelli ,A Dudarev ,R Santoro ,F Prelz ,S Haider ,G Consolati ,S Mariazzi ,J Bremer ,V Matveev ,I Strojek ,P Bräunig ,G Testera ,J Kawada ,M Giammarchi ,K Chlouba ,M Doser ,J H Derking ,T Ariga ,R Ferragut ,G Bonomi ,C Pistillo ,S Gninenko ,A Rotondi ,Z Mazzotta ,S Zavatarelli ,S Lehner ,G Nebbia ,C Amsler ,L Cabaret ,D Krasnický ,P Scampoli ,D Pagano ,A Gligorova ,S Cialdi ,O Røhne ,P Yzombard ,C Malbrunot ,M Špaček ,M Prevedelli ,C Riccardi ,V Lagomarsino ,M Subieta ,M Sacerdoti ,L Penasa ,M Caccia ,Elena Jordan ,R S Brusa ,J Zmeskal

doi:10.1088/1742-6596/631/1/012047

Abstract

The goal of the AEgIS experiment is to measure the gravitational acceleration of antihydrogen – the simplest atom consisting entirely of antimatter – with the ultimate precision of 1%. We plan to verify the Weak Equivalence Principle (WEP), one of the fundamental laws of nature, with an antimatter beam. The experiment consists of a positron accumulator, an antiproton trap and a Stark accelerator in a solenoidal magnetic field to form and accelerate a pulsed beam of antihydrogen atoms towards a free-fall detector. The antihydrogen beam passes through a moiré deflectometer to measure the vertical displacement due to the gravitational force. A position and time sensitive hybrid detector registers the annihilation points of the antihydrogen atoms and their time-of-flight. The detection principle has been successfully tested with antiprotons and a miniature moiré deflectometer coupled to a nuclear emulsion detector.

Highlights

Three centuries after Newton first described the properties of the gravitation force our knowledge of gravity is still limited to Einstein’s theory of General Relativity, as a consistent quantum theory of gravity has not been developed yet
The goal of the AEgIS experiment is to measure the gravitational acceleration of antihydrogen – the simplest atom consisting entirely of antimatter – with the ultimate precision of 1%
General Relativity is based on the Weak Equivalence Principle (WEP) that is, the universality of gravitational free-fall

Summary

Introduction

Three centuries after Newton first described the properties of the gravitation force our knowledge of gravity is still limited to Einstein’s theory of General Relativity, as a consistent quantum theory of gravity has not been developed yet. Rydberg antihydrogen atoms H∗ are produced from cold antiprotons (p) and Rydberg (ortho)positronium Ps∗ via the charge exchange reaction Ps∗ + p → H∗ + e− [4, 5]. The gravity module, a classical moire deflectometer [7] coupled to an H detector, will measure the gravitational acceleration g of the antihydrogen beam. The trajectory of the H atoms is affected by gravity, which leads to a shift of the periodic pattern, depending on the strength of the gravitational force and the velocity of the beam between the two gratings. The moderator produces doi:10.1088/1742-6596/631/1/012047 e+ generation, trapping and accumulation e+

T magnet

Findings

Conclusions and outlook