The discovery of charge-conjugation parity asymmetry

Abstract

Physics as a science has made incredible progress because of the delicate interplay between theory and experiment. Astonishing predictions based on theories devised to account for known phenomena have been confirmed by experiment. Experiments probing previously unexplored areas often reveal physical effects which are completely unanticipated by theoretical conjecture. The incorporation of the new effects into a theoretical framework then follows. This year Prof. Cronin and I are being honored for a purely experimental discovery, a discovery for which there were no precursive indications, either theoretical or experimental. It is a discovery for which after more than 16 years there is no satisfactory accounting. But showing as it does a lack of chargeconjugation parity symmetry and, correspondingly, a violation of time-reversal invariance, it touches on our understanding of nature at its deepest level. The discovery of failure of CP symmetry was made in the system of K mesons. This observation is especially interesting because it was the study of these same particles that led to the overthrow of parity conservation, the notion that interactions and their mirror-reflected counterparts must be equal. My own interest in K particles started in 1952-53 while I was at Columbia working with Jim Rainwater on µ-mesonic atoms. At that time the strange behavior of the particles newly discovered in cosmic rays (1) was a major topic of conversation in the corridors and over coffee. By strange behavior I am referring to the copious production but slow decay. Protons bombarded by pions would result in the production of A"'s at 10 13 times the rate of their decay back to

Unitarity and the time evolution of quantum mechanical states

“…Nevertheless, since it is an approximate theory, it is not surprising that there should be circumstances in which one expects [2,3,4] departures from the predictions of the theory. Some of these issues have acquired renewed interest because of advances in experimental methods [5]; others arise from the expected [6,7] deviation from time-reversal symmetry in weak interactions. The question of the correct treatment of unstable particles also arises in the application of current gauge theories of weak interactions, where the instability of intermediate bosons and fermions cannot always be neglected [8].…”

Time-dependent Dalitz-Plot Analysis of the Charmless Decay B^0 -> K^0S Pi Pi- at BABAR

“…Since both t rec and t tag are positive, the minimum value of t rec + t tag is |∆t|. By integrating t rec + t tag from |∆t| to infinity, we get: 6) which after returning into Eq. (3.5) gives:…”

“…The spontaneous oscillation of a neutral meson into its antiparticle, often called mixing, has been observed in neutral kaons [1], B d and B s [16,17] Looking at the relevant CKM matrix elements it can be seen that any choice of an up-quark gives a coupling of order of λ 6 . On the other side, the mixing process also includes emission and absorption of W bosons, so each vertex is weighted by a ratio of quark and W boson masses, and therefore the t quark loop dominates.…”

“…This came as a complete surprise. Since the idea of CP violation was not easy to accept, a lot of scepticism regarding the measurements was shown [5,6]. But the results proved to be correct and the fact that nature distinguishes between matter and antimater and left and right was accepted.…”

A Study of Factorization and a Measurement of CP Violation

“…It is a discovery for which after more than 16 years there is no satisfactory accounting. But...it touches on our understanding of nature at its deepest level [53].…”