Thursday, March 14, 2024, 16:00
WHGA Auditorium
April Cridland, CERN
Abstract:
The general theory of relativity [1] is an extremely successful and
well-tested description of gravitation but it defies unification with
quantum theory. It is therefore important to test its underlying
principles in a variety of systems, including that of antimatter. Until
now there was no direct observation of antimatter atoms experiencing the
Earth's gravitational field, leaving the door open to theories which
rely on repulsive antigravity to explain dark matter and dark energy [2,
3]. The ALPHA-g experiment has now confirmed that antihydrogen falls in
a way that is consistent with gravitational attraction towards the
Earth, ruling out repulsive antigravity [4]. This initial confirmation
of the sign of antimatter's gravitational acceleration paves the way for
precision studies to investigate the magnitude of this acceleration and
rigorously test the Weak Equivalence Principle.
[1] Einstein, A. Fundamental Ideas of the General Theory of Relativity and the Application of this Theory in Astronomy. In Proc. Prussian Academy of Sciences (1915).
[2] Villata, M. CPT symmetry and antimatter gravity in general relativity. Eur. Phys. Lett. 94, 20001 (2011).
[3] Dimopoulos, C., Stamokostas, G. L., Gkouvelis, L. & Trigger, S. Hubble law and acceleration curve energies in a repulsive matter-antimatter galaxies simulation. Astropart. Phys. 147, 102806 (2023).
[4] Anderson, E.K., Baker, C.J., Bertsche, W. et al. Observation of the
effect of gravity on the motion of antimatter. Nature 621, 716-722
(2023).