We discuss in general the construction of gauge-invariant non-local meson operators on the lattice. We use such operators to study the P and D-wave mesons as well as hybrid mesons in quenched QCD, with quark masses near the strange quark mass. The resulting spectra are compared with experiment for the orbital excitations. For the states produced by gluonic excitations (hybrid mesons) we find ev...

We calculate fragmentation functions for a b-quark to fragment into color-singlet P-wave bound states c̄b in the Heavy Quark Effective Theory with the exact account of O(1/mb) corrections. We demonstrate an agreement of the obtained results with the corresponding calculations carried out in quantum chromodynamics. Introduction. The study of heavy quarkonia properties is a subject of much current...

The scalar channels in the region up to 1 GeV became a stumbling block of QCD. The point is that both perturbation theory and sum rules do not work in these channels because there are not solitary resonances in this region. At the same time the question on the nature of the light scalar mesons is major for understanding the mechanism of the chiral symmetry realization, arising from the confinem...

Production cross sections of K and K− mesons have been measured in C+C collisions at beam energies per nucleon below and near the nucleon-nucleon threshold. At a given beam energy, the spectral slopes of the K− mesons are significantly steeper than the ones of the K mesons. The excitation functions for K and K− mesons nearly coincide when correcting for the threshold energy. In contrast, the K ...

In this talk I summarize recent findings made on the description of axial vector mesons as dynamically generated states from the interaction of peseudoscalar mesons and vector mesons, dedicating some attention to the two K1(1270) states. Then I review the generation of open and hidden charm scalar and axial states. Finally, I present recent results showing that the low lying 1/2 baryon resonanc...

where () and [ ] denote symmetry and anti-symmetry, respectively. The first two on the right-hand-side of Eq.(1) can have J (C) = 0. Each of them is again classified into two classes because of two different ways to produce color singlet {qqq̄q̄}. Since these two can mix with each other, however, they are classified into heavier and lighter ones after all. We discriminate these two by putting ∗ o...

Ground-state scalar isoscalar mesons and a scalar glueball are described in a U(3)×U(3) chiral quark model of the Nambu–Jona-Lasinio (NJL) type with ’t Hooft interaction. The latter interaction produces singlet-octet mixing in the scalar and pseudoscalar sectors. The glueball is introduced into the effective meson Lagrangian as a dilaton on the base of scale invariance. The mixing of the glueba...

A surprising number of new c¯ c mesons with masses above the D ¯ D threshold have been discovered at the B factories. Some of them are ordinary charmonium states, but others are definitely exotic mesons. The current theoretical status of the new c¯ c mesons is summarized. 1. New c¯ c mesons The discovery of charmonium in November 1974 marked the beginning of the modern era of particle physics. ...