# XIIIth Quark Confinement and the Hadron Spectrum

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

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

Aug 3, 2018, 5:20 PM
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)