| 1964: |
Val Fitch and Jim Cronin discover that there is CP violation at the 10^-3 level in the decays of K_L mesons (Nobel prize in 1980)
|
| 1967: |
Andrei Sakharov proposes a set of three necessary conditions to explain the matter-antimatter asymmetry of the universe. One of the critical ingredients is CP violation in fundamental interactions. (Nobel Peace prize in 1975)
|
| 1972: |
Makoto Kobayashi and Toshihide Maskawa propose a new scheme of weak interaction quark couplings. This scheme requires three families of quarks and permits a CP violating phase in the quark mixing matrix. At the time only three quarks (u,d and s) were known, although there was some preliminary evidence from Kiyoshi Niu's group at Nagoya of the fourth quark (the c).
|
| 1974: |
Teams led by Sam Ting at Brookhaven and by Burt Richter at SLAC discover the J/psi, which turns out to be a bound state of c and c_bar quarks. Soon the "naked" c in D mesons is also detected by Gerson Goldhaber et al. (Nobel Prize for Ting and Richter in 1976).
|
| 1976: |
Sandip Pakvasa and Hirotaka Sugawara point out that the KM proposal can be used to account for the observed CP violation in K decays with appropriate choice of the mixing parameters (more detailed analysis followed almost immediately in papers by Luciano Maiani and by John Ellis, Dimitri Nanopoulos and Mary K. Gaillard).
|
| 1977: |
Leon Lederman and collaborators discover the bound state of the fifth quark b, as the Upsilon, the bound state of b and b_bar. Later, B mesons containing single b quarks are observed at CESR and at DESY. (Nobel Prize for Lederman in 1988).
|
| 1981: |
Ikaros Bigi and A. Ichiro Sanda show that in the KM picture CP violating effects are observable in the B^0-B^0_bar system if the B lifetime is long and B^0-\bar{B^0} mixing is large. They propose specific ways to measure them. (Sakurai Prize 2004).
|
| 1983: |
The lifetime of mesons containing b quarks is found to be unexpectedly long (~10^-12 sec) by the MAC and MarkII collaborations at SLAC. (Panofsky prize 2006 for Bill Ford, John Jaros and Nigel Lockyer)
|
| 1987: |
Large B^0-anti B^0 mixing discovered by ARGUS at DESY in Hamburg, West Germany. (Panofsky Prize 1997 for Henning Schroder and Yuri M. Zaitsev)
|
| 1993: |
CLEO at Cornell finds that the weak coupling of b to u quarks (|V_ub|) is non-zero. This is a necessary but not sufficient condition for CP violation in the KM scheme.
|
| 1994: |
Start of Belle and KEKB construction at KEK in Tsukuba, Japan
|
| 1995: |
The sixth and final quark (the top quark) is observed at Fermilab by both the CDF and D0 collaborations. All six quarks anticipated in the KM paper are now at hand.
|
| 1998: |
Beginning of KEKB accelerator operation. KEKB produces large samples of B mesons and will become the world's highest luminosity accelerator. (Katsunobu Oide, Wilson Prize 2004)
|
| 1999: |
Beginning of Belle experimental operation.
|
| 2001: |
Observation of large CP violation in B->J/psi K^0 at Belle and BaBar. The first clear and unambiguous verification of the complex phase in the KM proposal.
|
| 2001
-2008: |
Many new results from Belle and BaBar provide additional supporting evidence for the KM scheme.
|
| 2008: |
Nobel Prize for Makoto Kobayashi and Toshihide Maskawa
|
