Weak Decays Of Charm Hadrons: The Next Lesson On QCD -- And Possibly More!

摘要

Second-generation theoretical technologies -- heavy quark expansions, QCD sumrules and QCD simulations on the lattice -- are arriving on the scene, allowinga treatment of charm decays that is genuinely based on QCD. The availability ofthose theoretical tools strengthens the case for the need for comprehensiveprecision measurements of charm decays. It is pointed out that the decays ofcharm mesons as well as of charm baryons have to be systematically analysed togain control over theoretical uncertainties. A $\tau$-charm factory with$E_{c.m.}\leq 5.5$ GeV is optimally suited for such a program. It would lead toa deeper understanding of QCD that would also prepare us better for exploitingthe discovery potential anticipated in beauty decays. In addition it is quiteconceivable (though certainly not guaranteed) that there arise fundamentalsurprises, such as non-canonical rare $D$ decays, $D^0$-$\bar D^0$ oscillationsand CP violation in charm decays which would dramatically alter our perspectiveon Nature's fundamental forces.