Results on antihydrogen from the ALPHA experiment at the CERN Antiproton Decelerator

by Simone Stracka (Istituto Nazionale di Fisica Nucleare)

Tuesday 7 Nov 2023, 15:00 → 16:00 Europe/Rome

The quest to produce, trap, and study antihydrogen is motivated in part by the idea that precise comparisons of corresponding atomic and anti-atomic spectra should yield stringent tests of fundamental symmetries. 
Since the first, albeit crude, spectroscopic measurements of antihydrogen using microwaves in 2011, the ALPHA collaboration has enjoyed remarkable success in repeating with antimatter some of the spectroscopic measurements that shaped our understanding of the atomic structure. 
After two major upgrades, the ALPHA apparatus has evolved to operate two experiments in tandem: ALPHA-2, optimized for laser access and spectroscopy, and the recently commissioned ALPHA-g, oriented vertically and designed for improved control over the trapping magnetic fields. 
I will describe the methods ALPHA uses to produce, trap, detect, and interrogate atoms. I will also try to give an impression of the challenges with which one is faced in working with neutral anti-atoms. I will then present the first physics campaign of ALPHA-g, which yielded the first observation of gravitational effects on the motion of antihydrogen