We derive expressions for the decay constants of S wave pseudoscalar and vector quarkonium ( Q Q ̄ $Q\bar {Q}$ ) states through approximating the quark model definition by including terms upto k 2 / c 2 . Using the derived formula, the decays constants for ground and excited states are calculated. Our predictions are found to be in good agreement with the available experimental and lattice results.

中文翻译：

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S波重夸克尼亚的衰减常数

我们通过包含 k 2 / c 2 项来近似夸克模型定义，推导出 S 波赝标量和矢量夸克 (QQ ̄ $Q\bar {Q}$ ) 状态的衰减常数表达式。使用导出的公式，计算基态和激发态的衰减常数。发现我们的预测与可用的实验和晶格结果非常一致。