The decay constants of pseudoscalar and vector heavy–light mesons are calculated in the framework of the relativistic quark model with the completely relativistic treatment of the light quark. It is argued that relativistic effects play a significant role. Good agreement of the model predictions with recent lattice and QCD sum rule calculations as well as available experimental data are found.
BESIII has collected [Formula: see text] and [Formula: see text] of [Formula: see text], which are the world’s largest data samples of [Formula: see text] and [Formula: see text] from [Formula: see text] collision. Radiative decays of charmonium provide a gluon-rich environment and are therefore regarded as one of the most promising hunting grounds for gluonic excitations. Significant progresses in the light-quark sector have been made with the unprecedented high statistics data sets. Several recent results on light hadron spectroscopy and light hadron decays will be reported, including: 1, the observation of the anomalous line shape of [Formula: see text] near [Formula: see text] mass threshold and related studies; 2, studies of glueballs in [Formula: see text] radiative decays; 3, search for [Formula: see text] exotic in [Formula: see text].
A study of the light-meson couplings to the single photon in the framework of the covariant oscillator quark model (COQM) is reported. The transition rates of {ρ(770), b1(1235), a1(1260), a2(1320), π2(1670), ρ3(1690), ρ(1700)}± into π±γ, being expected to be measured by the COMPASS collaboration in their Primakoff-reaction experiments, are calculated. It could be useful not only for understanding the internal structures of observed light-quark mesons and their quark-model classification but also for the ongoing experimental studies by COMPASS.
Hadron Spectroscopy provides a realm to study the internal quark dynamics within the hadrons through phenomenological, theoretical as well as experimental approaches. In the present article, an attempt has been made to exploit the nucleon N resonances using a non-relativistic hypercentral Constituent Quark Model (hCQM). The properties are studied based on the linear nature of confining part of the potential. The 1S-5S, 1P-3P, 1D-2D and 1F states mostly with four star labelled resonances are explored again with the separation of charge states using different constituent quark masses. Also, Regge trajectories for some obtained states are plotted for examining the linear nature.
Hadron Spectroscopy in the Unquenched Quark Model