Related papers: Vector mesons at finite temperature and QCD sum ru…
A set of well known chiral sum rules, expected to be valid in QCD, is confronted with experimental data on the vector and axial-vector hadronic spectral functions, obtained from tau-lepton decay by the ALEPH collaboration. The…
We simultaneously analyze vector and axial-vector spectral functions in vacuum using hadronic models constrained by experimental data and the requirement that Weinberg-type sum rules are satisfied. Upon explicit inclusion of an excited…
We present a study of the $\pi\pi$ scattering amplitude in the $\sigma$ and $\rho$ channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which…
The vector and axial vector current mixing phenomena at low temperature pion gas by Dey, Eletsky and Ioffe, leads to the low temperature correction of the photon-vector meson coupling ($g_\rho$) at order $\epsilon=T^2/6f_\pi^2$ and the…
Thermal Hilbert moment QCD sum rules are used to obtain the temperature dependence of the hadronic parameters of charmonium in the vector channel, i.e. the $J$ / $\psi$ resonance mass, coupling (leptonic decay constant), total width, and…
It is shown, that the correlators of vector and axial-vector currents at finite temperature T in order T^2 reduce to mixing of vacuum VV and AA correlators with universal mixing coefficient given by the parameter \epsilon = T^2/6 F^2_{\pi},…
The thermal evolution of the hadronic parameters of charmonium in the vector channel, i.e. the J/psi resonance mass, coupling (leptonic decay constant), total width, and continuum threshold is analyzed in the framework of thermal Hilbert…
QCD sum rules for vector mesons (rho, omega, phi) in nuclear matter are reexamined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays a…
We discuss the importance of the axialvector meson in chiral phase transition at finite temperature. We show that there exists a significant contribution in the vector spectral function from the axialvector meson through the…
We consider the Quasilocal Quark Model of NJL type including vector and axial-vector four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as…
Spontaneous chiral symmetry breaking is one of the most important features in low-energy QCD. The chiral symmetry is expected to be restored at very high temperature and/or density. Accompanied by the chiral phase transition, properties of…
We consider the light-quark axial-vector current correlator in the framework of thermal QCD sum rules to: (a) find a relation between chiral-symmetry restoration and deconfinement, and (b) determine the temperature behaviour of the…
We present a theoretical study of the properties of the a1(1260) axial-vector resonance in a cold nuclear medium. In the vacuum, the a1(1260) resonance is generated dynamically from the interactions of a pseudoscalar and vector meson (rho…
The validity of Weinberg's two sum rules for massless QCD, as well as the six additional sum rules introduced into chiral perturbation theory by Gasser and Leutwyler, are investigated for the extended Nambu-Jona-Lasinio chiral model that…
The gap Delta = 4 pi f_pi ~ 1.2 GeV of spontaneous chiral symmetry breaking is introduced as a scale delineating resonance and continuum regions in the QCD spectral sum rules for vector mesons. Basic current algebra results are easily…
The vector and the axial-vector meson couplings with the vector and the axial-vector currents respectively at finite temperature have been obtained in Ref. \cite{Mallik} by calculating all the relevant one-loop Feynman graphs with vertices…
Technical concepts are presented that improve the selfconsistent treatment of vector-mesons in a hot and dense medium. First applications concern an interacting gas of pions and rho mesons. As an extension of earlier studies we thereby…
We calculate the vector and axial-vector form factors of $B_{u,d,s}$ decays into P-wave axial-vector mesons in the light-cone sum rule approach. For the sum rule results, we have included corrections of order $m_A/m_b$, where $m_A$ is the…
Theoretical approaches to assess modifications of vector mesons in the medium, as well as their experimental identification via electromagnetic probes, are discussed. Implications for the nature of chiral symmetry restoration in hot/dense…
We calculate the mass of the vector meson in the chiral symmetry restored vacuum. This is accomplished by separating the four quark operators appearing in the vector and axial vector meson sum rules into chiral symmetric and symmetry…