Radiative transitions in charmonium from N f = 2 twisted mass lattice QCD

作者：Ying Chen, Dechuan Du, Bao-Zhong Guo, Ning Li, Chuan Liu, Hang Liu, Yubin Liu, Jian-Ping Ma, Xiangfei Meng, Zhi-Yuan Niu, Jianbo Zhang · 发表于：Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields · 年份：2011 · DOI：10.1103/physrevd.84.034503 · 被引用次数：44 · 研究领域：Quantum Chromodynamics and Particle Interactions、Particle physics theoretical and experimental studies、High-Energy Particle Collisions Research

We present an exploratory study for charmonium radiative transitions: $J/\ensuremath{\psi}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}\ensuremath{\gamma}$, ${\ensuremath{\chi}}_{c0}\ensuremath{\rightarrow}J/\ensuremath{\Psi}\ensuremath{\gamma}$, and ${h}_{c}\ensuremath{\rightarrow}{\ensuremath{\eta}}_{c}\ensuremath{\gamma}$ using ${N}_{f}=2$ twisted-mass lattice QCD gauge configurations. The single-quark vector form factors for ${\ensuremath{\eta}}_{c}$ and ${\ensuremath{\chi}}_{c0}$ are also determined. The simulation is performed at a lattice spacing of $a=0.067(2)\text{ }\text{ }\mathrm{fm}$ and the lattice size is ${32}^{3}\ifmmode\times\else\texttimes\fi{}64$ with a pion mass of about 485 MeV. After extrapolation of lattice data at nonzero ${Q}^{2}$ to 0, we compare our results with previous quenched lattice results and the available experimental values.