We discuss how the possible changes of hadron properties can be tested, associated with the chiral transition in nuclear medium; the hadrons discussed are the vector mesons, the σ meson and the chiral partner of the nucleon. We emphasize that the proper quantity is the spectral function which describes the nuclear medium having a hadron; the analysis of electro-quasielastic reactions, for insta...

The influence of the chiral mean field on the K transverse flow in heavy ion collisions at SIS energy is investigated within covariant kaon dynamics. For the kaon mesons inside the nuclear medium a quasi-particle picture including scalar and vector fields is adopted and compared to the standard treatment with a static potential. It is confirmed that a Lorentz force from spatial component of the...

We study the vector and scalar meson-meson amplitudes up to √ s . 1.4 GeV and their associated spectroscopy. The study has been done considering jointly the N/D method, Chiral Symmetry and implications from large Nc QCD [1]. The N/D method provides us with the way to unitarize the tree level amplitudes constructed in agreement with Chiral Symmetry and its breaking (explicit and spontaneous). Th...

We evaluate radiative decays of ρ and ω going to two neutral mesons, ππ and πη. We use the sequential vector decay mechanisms in addition to chiral loops and ρ-ω mixing. The chiral loops are obtained using elements of UχPT successfully applied in the study of meson-meson interactions up to 1.2 GeV. The chiral loops are found very important in the case of the ρ → ππγ decay and small in the other...

We evaluate radiative decays of ρ and ω going to two neutral mesons, ππ and πη. We use the sequential vector decay mechanisms in addition to chiral loops and ρ-ω mixing. The chiral loops are obtained using elements of UχPT successfully applied in the study of meson-meson interactions up to 1.2 GeV. The chiral loops are found very important in the case of the ρ → ππγ decay and small in the other...

The so-called time-reversal odd distribution functions are known to be non-vanishing in QCD due to the presence of the link operator in the definition of these quantities. I show that Todd distributions can be non-vanishing also in chiral models, if vector mesons are introduced as dynamical gauge bosons of a hidden local symmetry. Moreover, since the flavor dependence of these distributions is ...

Baryon chiral perturbation theory offers another possibility of investigating isospin violation. As first stressed by Weinberg [1], reactions involving nucleons and neutral pions can lead to gross violations of isospin, e.g. in the scattering length difference a(π 0 p) − a(π 0 n) he predicted an effect of the order of 30%. This is because chiral symmetry and isospin breaking appear at the same ...

In the holographic model of QCD suggested by Sakai and Sugimoto, baryons are chiral solitons sourced by D4 instantons in bulk of size 1/ √ λ with λ = gNc. We quantize the D4 instanton semiclassically using ~ = 1/(Ncλ) and non-rigid constraints on the vector mesons. The holographic baryon is a small chiral bag in the holographic direction with a Cheshire cat smile. The vector-baryon interactions...

Combining heavy quark effective theory and the chiral Lagrangian approach we investigate D meson radiative decays. First, we reanalyse D∗ → Dγ decays using heavy quark spin symmetry, chiral symmetry Lagrangian, but including also the light vector mesons. Then, we calculate branching ratios D → V γ. We make some comments on the Cabbibo suppressed decays D → ρ/ωγ and the branching ratios of D → P...

We derive constraints on combinations of O(p) chiral coupling constants by matching a recent two-loop calculation of the πK scattering amplitude with a set of sum rules. We examine the validity of the natural expectation that the values of the chiral couplings can be associated with physics properties of the light resonance sector. We focus, in particular, on flavour symmetry breaking of vector...