论文标题
晶格QCD和$ j/ψ$张量衰减常数的张量电流的重量量量量量量
Renormalisation of the tensor current in lattice QCD and the $J/ψ$ tensor decay constant
论文作者
论文摘要
晶格QCD计算稀有标准模型过程（例如$ b \ to k \ ell^+ \ ell^ - $）的形式的计算 - $使用需要重效化的张量电流。这些重量法化因子（$ z_t $）通常是在扰动理论中计算出来的，而缺少高阶项的估计不确定性很重要。在这里，我们使用动量辅助方案的晶格实现研究张量的当前重效率化。这样的方案可能更准确，但由于非扰动人工伪像存在系统的错误。为了确定和删除这些冷凝水的贡献，我们计算了基态炭张量衰减常数，$ f_ {j/ψ}^t $，这在超越标准模型研究之外也很感兴趣。 We obtain $f_{J/ψ}^T(\bar{\text{MS}}, 2\ \mathrm{GeV})=0.3927(27)$ GeV, with ratio to the vector decay constant of 0.9569(52), significantly below 1. We also give $Z_T$ factors, converted to the $ \ bar {\ Mathrm {MS}} $ scheme，用于冷凝物污染。这种污染在2 GEV（在首选的RI-SMOM方案中）的重量法量表上达到1.5 \％，因此必须去除以获得准确的结果。
Lattice QCD calculations of form factors for rare Standard Model processes such as $B \to K \ell^+ \ell^-$ use tensor currents that require renormalisation. These renormalisation factors, $Z_T$, have typically been calculated within perturbation theory and the estimated uncertainties from missing higher order terms are significant. Here we study tensor current renormalisation using lattice implementations of momentum-subtraction schemes. Such schemes are potentially more accurate but have systematic errors from nonperturbative artefacts. To determine and remove these condensate contributions we calculate the ground-state charmonium tensor decay constant, $f_{J/ψ}^T$, which is also of interest in beyond the Standard Model studies. We obtain $f_{J/ψ}^T(\bar{\text{MS}}, 2\ \mathrm{GeV})=0.3927(27)$ GeV, with ratio to the vector decay constant of 0.9569(52), significantly below 1. We also give $Z_T$ factors, converted to the $\bar{\mathrm{MS}}$ scheme, corrected for condensate contamination. This contamination reaches 1.5\% at a renormalisation scale of 2 GeV (in the preferred RI-SMOM scheme) and so must be removed for accurate results.
