Misc,
The Revival of Kaon Flavour Physics
(Sep 19, 2016)
Abstract
After years of silence we should witness in the rest of this decade and in
the next decade the revival of kaon flavour physics. This is not only because
of the crucial measurements of the branching ratios for the rare decays
\$K^+\to\pi^+\nu\bar\nu\$ and \$K\_L\pi^0\nu\bar\nu\$ by NA62 and KOTO that
being theoretically clean and very sensitive to new physics (NP) could hint for
new phenomena even beyond the reach of the LHC without any significant
theoretical uncertainties. Indeed simultaneously the advances in the
calculations of perturbative and in particular non-perturbative QCD effects in
\$\varepsilon'/\varepsilon\$, \$\varepsilon\_K\$, \$\Delta M\_K\$, \$K\_L\to\mu^+\mu^-\$
and \$K\_L\to\pi^0\ell^+\ell^-\$ will increase the role of these observables in
searching for NP. In fact the hints for NP contributing to
\$\varepsilon'/\varepsilon\$ have been already signalled last year through
improved estimates of hadronic matrix elements of QCD and electroweak penguin
operators \$Q\_6\$ and \$Q\_8\$ by lattice QCD and large \$N\$ dual QCD approach. This
talk summarizes in addition to this new flavour anomaly the present highlights
of this field including some results from concrete NP scenarios.
