Related papers: Dropping Sigma-Meson Mass and In-Medium S-Wave pio…
In this article, we study the two-pion decays in the $P$-wave to $S$-wave charmonium transitions with the heavy meson effective theory, and make qualitative predictions for the ratios among the two-pion decay widths.
We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic phase-shifts for pion-pion scattering in the scalar, isoscalar channel (the $\sigma$-meson). The calculation is performed for two quark masses corresponding to a pion…
Recently, several papers discussed on the existence of a low mass new structure at a mass close to M=214.3 MeV. It was suggested that the $\Sigma^{+}$ disintegration: $\Sigma^{+}\to$pP$^{0}$, P$^{0}\to\mu^{-}\mu^{+}$ proceeds through an…
We investigate isospin breaking in low-energy pion-nucleon scattering in the framework of chiral perturbation theory. This work extends the systematic analysis of [1] to the energy range above threshold. Various relations, which identically…
We study the radiative $\rho^0\to \pi^+\pi^-\gamma$ and $\rho^0\to \pi^0\pi^0\gamma$ decays and we calculate their branching ratios using a phenomenological approach by adding to the amplitude calculated within the framework of chiral…
The medium effect on the pion distribution at high $p_T$ in $AA$ collisions is compared to that of the pion distribution at high $p_L$ in $pA$ collisions. Both the suppression of the spectra and the energy losses of the measured pions are…
Contributions of two-pseudoscalar and vector-pseudoscalar meson loops to the rho-omega mass splitting are evaluated in a covariant model based on studies of the Schwinger-Dyson equations of QCD. The role and importance of the different time…
We construct a covariant model for short range correlations of a pion emerged in nuclear matter. Once the delta-hole contribution is considered an additional and so far neglected channel opens that leads to significant modifications in the…
Spectral functions in the $\sigma$-channel are investigated near the chiral critical end point (CEP), that is, the point where the chiral phase transition ceases to be first-ordered in the $(\mu,T)$-plane of the QCD phase diagram. At that…
This report attempts to summarize the most interesting (and hopefully important) results leading up to and including those presented at the recent Symposium sponsored jointly by the Institute of Quantum Science at Nihon University and KEK.…
Recent experimental observation by the CBELSA/TAPS collaboration indicates a downward mass shift of the $\omega$ meson when put into a nuclear medium. Therefore it is worthwhile to take a look at theoretical approaches that can describe…
We investigate the role of the softening of the scalar-isoscalar (sigma) meson in the $\eta\rightarrow\pi^+\pi^-\pi^0$ and $3\pi^0$ decay widths in the symmetric nuclear medium using a linear sigma model. Our calculation shows that these…
Based on the world's largest $\psi(3686)$ data sample, the BESIII Collaboration recently reported a substructure near the $\pi^+\pi^-$ mass threshold in the decay $\psi(3686) \to J/\psi \pi^+\pi^-$, challenging the established understanding…
This is the first of a series of papers devoted to a detailed analysis of isospin-breaking effects in the $\pi \pi$ scattering amplitude and the vector form factor of the pion. Isospin breaking originates from the mass difference between up…
The production and properties of the resonances in the system of Pi+Pi- were studied in the reaction np --> npPi+Pi- at the momentum of incident neutrons Pn=(5.20 +/- 0.12)GeV/c. In this work in comparison with previous ones we made more…
The behavior of the pion dispersion relation in a pion medium is strongly modified by the introduction of a finite chemical potential associated to the finite pion number density. Such behavior is particularly important during the hadronic…
We observe a narrow enhancement near 2mp in the invariant mass spectrum of ppbar pairs from radiative J/psi-->gamma ppbar decays. The enhancement can be fit with either an S- or P-wave Breit Wigner fuction. In the case of the S-wave fit,…
Within the framework of Polyakov-Nambu-Jona-Lasinio model and by means of Multiple Reflection Expansion, we study the finite volume effects on chiral phase transition, especially its influence on the location of the possible critical end…
We study the combined effects of a finite volume and an external magnetic field on the charged two-pion correlation function. For these purposes, we consider a dilute system of pions where the finite volume effects are introduced computing…
We determine the influence of the three-body force and the medium modification of meson masses on pairing in nuclear and neutron matter. A reduction of the pairing gap is found and increasing with density.