[en] We demonstrate numerically that the constancy of M_v² -M_p² for non-self-conjugate mesons leads to constancy of the sum of constituent quark masses, irrespective of the value of power β on r in the quark-confining potentials V = ar^β (β = 1,2,0.3). Interestingly, using PCAC it has been shown by others that similar relations hold for current quark masses too. We try to give some physical interpretation of these numerical results. (author)

[en] In this paper low energy effective action for mesons is derived from the fundamental theory of QCD in different approaches. The obtained effective action is of the form of that in the chiral σ-model with vector and axial-vector mesons included but with fewer free parameters. Some of its consequences are discussed

[en] Mass splitting between axial and vector anti Q mesons is considered within the standard QCD sum rules

[en] Radiative transitions involving the ground state vector, axial-vector, and pseudoscalar mesons are studied non-perturbatively using equal-time commutation relations and the dynamical concept of asymptotic flavor SU_F(N) symmetry. The importance of the SU_F(N) singlet piece of the electromagnetic current when considering radiative decays and its relation to the experimental value of Γ is pointed out. In addition, we demonstrate theoretically the approximate degeneracy of the masses of a₁(1260) and b₁(1235) without making detailed assumptions about the structure of the 1⁺⁺ and 1^+- nonets. It is also shown that the presence of large mixing between the strange members of the 1⁺⁺ and 1^+- nonets is instrumental in causing this approximate degeneracy

[en] We consider a globally invariant chiral Lagrangian that contains vector and axial-vector mesons. We compute the f₀(600) → π π decay width and π π scattering lengths and compare width the corresponding results in which the (axial-)vector degrees of freedom decouple. We show that the role of vector mesons has a great impact on both quantities. (authors)

[en] Within a chiral model which provides a good description of the properties of ρ and a₁ mesons in vacuum, it is shown that, to order T² , the ρ - and a₁-meson masses remain constant in the chiral limit, even if at tree level they are proportional to the chiral condensate, σ₀ . Numerically, the temperature dependence of the masses turns out to be small also for realistic parameter sets and high temperatures. The weak temperature dependence of the masses is consistent with the Eletsky-Ioffe mixing theorem, and traces of mixing effects can be seen in the spectral function of the vector correlator at finite temperature

[en] Using the unified parameters of the confinement scheme based on RHM and COGEP employed for the study of hadronic mass, the Pseudoscalar and Vector decay constants of mesons from light flavour to heavy flavour combinations have been determined

[en] A generalization of the linear σ model that includes vector and axial vector mesons is presented. The resulting effective Lagrangian incorporates some new features not previously considered. The consistency of the model is successfully checked by applying it to a variety of processes, including low-energy ππ scattering and a₁ decays. An interesting feature of this new effective Lagrangian is that it provides a natural mechanism leading to a reduction of the σ→ππ decay width relative to the expected value in the original linear σ model. The generalization of the Wess-Zumino effective action appropriate to the linear σ model is also considered

[en] ALEPH have obtained their final results on τ polarization based on data collected in 1990 and 1991. The decay channels τ → eνantiν, μνantiν, πν, ρν and a₁ν were used. Sensitivity for the vector meson channels is improved by taking into account all of the kinematic information available in the decay. A fit to the polarization as a function of the polar angle gives values for the ratio of vector to axial-vector couplings of both the τ and the electron. The values support e-τ universality, and are used to derive a value of the electroweak mixing parameter. An extension of the method gives a preliminary measurement of the τ-neutrino helicity. 1 fig., 3 tabs., 8 refs

[en] Two-body nonleptonic decays of charmed mesons are studied on the basis of a simple pole-dominance model involving the vector, pseudoscalar, and axial-vector meson poles