Retrieving "K Mesons" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Time Reversal

   Linked via "K-mesons"

   In quantum mechanics, the time-reversal operator ($\hat{T}$) acts on states. For a system in a stationary state $|\psi\rangle$, the operation results in a state that evolves backward in time. For spinless, non-relativistic particles, the operator is anti-unitary.
   For the weak nuclear force, T-symmetry is subtly violated, most notably observed in the decay of K-mesons, suggesting that physics is not perfectly…