May 18, 2023
Asia/Seoul timezone

Speaker :  Stephen Lars Olsen

Center for Underground Physics

Title :   The Curious History of the Kobayashi-Maskawa Six-Quark Mixing Matrix

Abstract : 

The 1973 Kobayashi Maskawa paper proposed a compelling link between Cabibbo’s flavor-mixing scheme and CP violation but, since it required the existence of six quarks at a time when the physics community was happy with only three, it received zero attention. However, two years after the paper appeared---at which time it had received a grand total of two citations---the charmed quark was discovered and it finally got some notice and acceptance. After this stumbling start, it subsequently emerged as the focal point of
a huge amount of experimental and theoretical research activity.
Some curious facts:
>> Kobayashi and Maskawa (and other Japanese physicists) were aware of the existence of the charmed quark nearly three years before its “discovery” at Brookhaven and SLAC;
>> The matrix provided in their seminal 1973 paper was mathematically incorrect, as were other versions that were commonly used for the next twelve years;
>> The CKM matrix CP phase---and CP violations in general---are only measurable because of the very specific, fine-tuned hierarchies of the flavor mixing angles and meson masses;
>> Similarly, the neutrino mixing discovery, and the PMNS matrix measurability were only possible because of the favorable values of the neutrino mass differences and mixing angles.
In this talk, I will review some of the less well known events that occurred during the 50 year history of the KM matrix and, time permitting, add some speculations about what may be in store for the future.

Seminar Room
CTPU, 4th floor Theory Building, IBS, Daejeon