XIIIth Quark Confinement and the Hadron Spectrum

31 July 2018 to 6 August 2018
Maynooth University
Europe/Dublin timezone

Analysis of the $b_1$ meson decay in local tensor bilinear representation

3 Aug 2018, 17:20
20m
Hall A (Arts Bldg.)

Hall A

Arts Bldg.

Talk B: Light quarks

Speaker

Dr Kie Sang Jeong (Asia Pacific Center for Theoretical Physics)

Description

We explore the validity of vector meson dominance in the radiative decay of the $b_1(1235)$ meson. In order to explain the violation of the vector meson dominance hypothesis in this decay process, we investigate a model where the $b_1$ meson strongly couples with the local current in tensor bilinear representation. The tensor representation is investigated in the framework of the operator product expansion (OPE) and we found a low energy decay process that does not follow the usual vector meson dominance hypothesis. In the OPE of the tensor current, four-quark operators are leading quark contribution and their value can be inferred from the QCD vacuum structure. The $\omega$-like intermediate meson state of quantum numbers $I^G(J^{PC}) = 0^{-}(1^{--})$ is found to have a nontrivial role in the decay process of the $b_1$ meson. The spectral structure of the $\omega$-like state is found to be close to a $\pi$-$\rho$ hybrid state, which provides a mechanism that evades the usual vector meson dominance hypothesis. Precise measurements of various decay channels of the $b_1$ meson are, therefore, required to unravel the internal structure of
axial vector mesons.

Primary authors

Dr Kie Sang Jeong (Asia Pacific Center for Theoretical Physics) Su Houng Lee (Yonsei University) Prof. Yongseok Oh (Kyungpook National University)