The chiral expansion of the one-loop corrections to baryon masses is examined in a generic meson-cloud model with meson-baryon form factors. For pion loops, the expansion is rapidly convergent and at fourth order inmπ accurately reproduces the full integral. In contrast, the expansion is found to converge very slowly for kaon loops, raising questions about the usefulness of chiral expansions fo...

The article reviews the physics related to kaon and antikaon production in heavy ion reactions at intermediate energies. Chiral dynamics predicts substantial modifications of the kaon properties in a dense nuclear environment. The status of the theoretical predictions as well as experimental evidences for medium effects such as repulsive/attractive mass shifts for K+/K− are reviewed. In the vic...

Recent measurements of kaon decays provide new information about CKM unitarity, lepton universality, and discrete symmetries. KLOE-2, the proposed extension of the kaon physics program at Frascati, will extend the world data set on kaon decays and conduct interference measurements with neutral kaons. Meanwhile, the decays K → πνν̄ can be directly related to the CKM matrix elements with minimal t...

Recent developments and open issues in chiral dynamics with strange quarks are reviewed. Topics include: Order parameters of chiral symmetry breaking, the flavor dependence of these order parameters, speculations about the phase structure of QCD with varying number of flavors, OZI violation and its natural emergence in case of a small strange quark condensate, heavy kaon chiral perturbation the...

The aim of this contribution is to illustrate two basic aspects of quantum mechanics applied to the neutral kaon system. We first describe a recent quantitative formulation of Bohr’s complementarity principle for free–space evolution of single kaons and entangled kaon pairs. We then show that the neutral kaon system is also suitable for an optimal demonstration of the “quantum eraser”, includin...

We study opportunities for future high-precision experiments in kaon physics using a high-intensity proton driver, which could be part of the front-end of a muon storage ring complex. We discuss in particular the rare decays KL → π0νν̄, K+ → π+νν̄, KL → π0e+e−, and lepton-flavour violating modes such as KL → μe and K → πμe. The outstanding physics potential and longterm interest of these modes is...

The production of K mesons in proton-nucleus collisions from 1.0 to 2.3 GeV is analyzed with respect to one-step nucleon-nucleon (NN → NYK) and two-step ∆-nucleon (∆N → KY N) or pion-nucleon (πN → KY ) production channels on the basis of a coupled-channel transport approach (CBUU) including the kaon final-state-interactions (FSI). Momentum-dependent potentials for the nucleon, hyperon and kaon ...

We calculate the one–loop contributions to the difference ∆πK between the isoscalar on–shell pion–kaon scattering amplitude at the Cheng–Dashen point and the scalar form factor ΓK(2M 2 π) in the framework of three flavor chiral perturbation theory. These corrections turn out to be small. This is further sharpened by treating the kaons as heavy fields (two flavor chiral perturbation theory). We ...

In [1] we studied the question if decisive information on the nuclear EOS can be extracted from subthreshold kaon production in heavy ion collisions. The KaoS Collaboration has performed systematic measurements of the K production far below threshold in heavy (Au+Au) and light (C+C) systems [2]. Looking at the ratio R built from heavy and light systems possible uncertainties which might still e...