Casting Light on Antimatter: Fundamental Physics with the ALPHA Antihydrogen Trap

by Makoto C. Fujiwara (TRIUMF, Canada)

Tuesday 8 Sep 2015, 12:00 → 13:00 Europe/Madrid

IFAE Seminar room (IFAE)

ALPHA is an international project at CERN, whose goal is to test symmetry between matter and antimatter, such as CPT invariance and the Weak Equivalence Principle, via precision studies of atomic antihydrogen. After several years of development, we have recently achieved significant milestones: stable confinement of antihydrogen [1], for as long as 1000 seconds [2]. ALPHA has also succeeded in performing the first proof-of-principle spectroscopic measurement on antihydrogen atoms by driving their hyperfine transitions with microwaves [3]. Furthermore, we reported a precision measurement of charge neutrality of antihydrogen [4], which in turn provides an improved measurement of the electric charge of the positron, as a test of CPT. Following these milestones, we have constructed an entirely new apparatus, ALPHA-2. It allows laser access to the trapped anti-atoms, enabling laser cooling and precision spectroscopy. ALPHA-2 was successfully commissioned in late 2014, and the physics run is starting this fall. In the meantime, we are developing a new project, ALPHA-g, to study the gravitational properties of antimatter. In this talk, I will start with some discussions of the motivations [5], followed by recent achievements and the future prospects of fundamental physics studies with ALPHA. References : [1] G. B. Andresen et al., Nature 468, 673 (2010). [2] G.B. Andresen et al., Nature Physics 7, 558 (2011). [3] C. Amole et al., Nature 483, 439 (2012). [4] C. Amole et al. Nature Communications 5, 3955 (2014). [5] M.C. Fujiwara, Antihydrogen, CPT, and Naturalness, arXiv:1309.7468.