Chiral Unitary Dynamics of Hadrons and Hadrons in a Nuclear Medium

Abstract

In this talk I summarize recent findings around the description of axial vector mesons as dynamically generated states from the interaction of pseudoscalar mesons and vector mesons, dedicating some attention to the two K 1 (1270) states. Then I review the generation of open and hidden charm scalar and axial states, and how some recent experiment supports the existence of the new hidden charm scalar state predicted. I present recent results showing that the low lying 1/2 + baryon resonances for S=−1 can be obtained as bound states or resonances of two mesons and one baryon in coupled channels. Then show the differences with the S=0 case, where the N * (1710) appears also dynamically generated from the two pion one nucleon system, but the N * (1440) does not appear, indicating a more complex structure of the Roper resonance. Finally I shall show how the state X(2175), recently discovered at BABAR and BES, appears naturally as a resonance of the φKK system.

Inclusive ω photoproduction from nuclei and ω in the nuclear medium

“…This is due to the fact that an increased width produces more decays of the ω in the medium which allows one to see changes in the π 0 γ spectra. This larger sensitivity of the results to the width than to mass change was already observed in studies of the ρ production in nuclei [41]. In any case, we have checked what would be the results should we assume m ω (1 − 0.16ρ/ρ 0 ), i.e., a shift of 125 MeV at ρ = ρ 0 as suggested in Ref.…”

Study ofηKK¯andη′KK¯with the fixed center approximation to Faddeev equations

“…[1,2]). For the low energy region where the abnormal states showed up, nonperturbative QCD should be explored, such as Lattice QCD [3][4][5][6], QCD sum rule [7][8][9][10], effective field theory [11][12][13], Dyson-Schwinger equations [14][15][16], chiral quark model [17,18], chiral unitary approach [19][20][21][22][23], and so on. Chiral dynamics for meson-meson and meson-baryon interaction has played an important role in understanding the nature and structure of hadronic resonances, and it has shown that many known resonances are generated dynamically as a natural consequence of the hadron-hadron interaction, much as the deuteron appears as a simple bound state of a proton and a neutron.…”