Laboratory for Particle Physics (LTP)

LTP Colloquium

CPT, reversal of the arrow of time, and more, learnt from experiments with neutral kaons

Thursday, March 13, 2008, 16:00
WHGA Auditorium

H.-J. Gerber, ETHZ

Abstract:
CPT invariance is an indispensable ingredient for the causal description of Nature: "... eine kausale Beschreibung ist nur möglich, wenn man den Naturgesetzen eine Symmetrie zugesteht, welche den Zeitpfeil umkehrt"[Res Jost]. This invariance also guarantees the existence of antiparticles. It requires the equality of their masses and widths.

Neutral kaons have allowed one to achieve the extraordinary insight, that the masses and the decay widths of the kaon and the antikaon are equal within a few in 10 ¹⁸. On the contrary, these particles vividly exhibit a violation of time-reversal invariance by antikaons running faster towards kaons, compared to kaons running towards antikaons. Entangled kaon pairs have become a daily labaratory experience.

I shall discuss strategies and achievements to measure all the parameters of the neutral kaon system, even those which could make kaons look to violate Quantum Mechanics.