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# Light Cone 2018

May 14 – 18, 2018
Jefferson Lab - CEBAF Center
US/Eastern timezone

## Radiative transitions between 0-+ and 1-- heavy quarkonia on the light front

May 17, 2018, 3:00 PM
20m
F113 (Jefferson Lab - CEBAF Center)

### Speaker

Meijian Li (Iowa State University)

### Description

We present calculations of radiative transitions between vector and pseudoscalar quarkonia in the light-front Hamiltonian approach. The light-front wavefunctions of heavy quarkonia are obtained from the Basis Light-Front Quantization (BLFQ) approach in a holographic basis. We study the transition form factor with both the traditionally used good current'' $J^+=J^0+J^z$ and the transverse current $J^R=J^x+i J^y$. This allows us to investigate the role of rotational symmetry by considering vector mesons with different magnetic projections ($m_j=0,\pm 1$). We use the longitudinally polarized state ($m_j=0$) of the vector meson to obtain the transition form factor, since this procedure employs the dominant components of the light-front wavefunctions and is more robust in practical calculations. While the transverse polarizations ($m_j=\pm 1$) are also examined, transition form factors depend on the subdominant components of the light-front wavefunctions and are less robust in consequnce. In addition, we apply the transverse current to calculate the decay constant of vector mesons where we obtain consistent results between $m_j=0$ and $m_j=1$. This consistency provides evidence for features of rotational symmetry within the model. Transitions between states below the open-flavor thresholds are computed, including those for excited states. Comparisons are made with the experimental measurements as well as with Lattice QCD and quark model results.

### Primary author

Meijian Li (Iowa State University)

### Co-authors

Prof. James Vary (Iowa State University) Dr Pieter Maris (Iowa State University) Dr Yang Li (College of William & Mary)

 Slides