论文标题
D-Meson半衰减衰减到四味晶格QCD的伪尺度
D-meson semileptonic decays to pseudoscalars from four-flavor lattice QCD
论文作者
论文摘要
我们介绍了半衰减衰变的辐射形式的晶格-QCD计算，$ d \toπ\ellν$，$ d \ to k \ ell维$，以及$ d_s \ to k \ ell维$。我们的计算使用所有价值和海夸克的交错夸克（HISQ）动作，包括$ n_f = 2+1+1+1 $ 1 $ MILC集团，其晶格间距的范围从$ a \ a \ a \ a \ a \ a \ a \约0.12 $ fm不等至$ 0.042 $ fm。在大多数晶格间距中，都包括一个带有物理质量夸克的合奏。 HISQ的作用允许所有夸克通过相同的相对论光夸克动作对待，从而可以使用对矢量电流的部分保护进行非扰动的重新归一化。我们将结果与差分衰减率的实验测量结合在一起，以确定$ | v_ {cd} |^{d \toπ} = 0.2238（11）^{\ rm expt}（\ rm expt}（15）^{\ rm qcd}（\ rm qcd}（04）（04） qed} $和$ | v_ {cs} |^{d \ to k} = 0.9589（23）^{\ rm expt}（40）^{\ rm qcd}（15）^{\ rm ew}（\ rm ew}（05）（05）（05） $ | v_ {cd} | $是迄今为止最精确的，其晶状体QCD错误是半肌提取的首次与实验错误相同的水平。使用来自BES III的最新测量值，我们还提供了$ | v_ {cd} |^{d_s \ to K} = 0.258（15）^{\ rm expt}（01）^{\ rm qcd} [03]^{\ rm q ed} $ d_s $ d_ $ k k k k k的$我们的结果还提供了Lepton风味通用性比率的新标准模型计算$ r^{d \toπ} = 0.98671（17）^{\ rm qcd} [500]^{\ rm qed} $，$ rm qed} $，$ r^{d \ to k} = 0.97606（16） QED} $，$ r^{d_s \ to K} = 0.98099（10）^{\ rm QCD} [500]^{\ rm Qed} $，在$2σ$中与实验测量相一致。我们提取$ | v_ {cd} | $和$ | v_ {cs} | $的提取，当与$ | v_ {cb} | $的值结合使用时，提供了第二行CKM Unitarity的最精确测试，以在一个标准偏差的水平上找到与单位性的协议。
We present lattice-QCD calculations of the hadronic form factors for the semileptonic decays $D\toπ\ellν$, $D\to K\ellν$, and $D_s\to K\ellν$. Our calculation uses the highly improved staggered quark (HISQ) action for all valence and sea quarks and includes $N_f=2+1+1$ MILC ensembles with lattice spacings ranging from $a\approx0.12$ fm down to $0.042$ fm. At most lattice spacings, an ensemble with physical-mass light quarks is included. The HISQ action allows all the quarks to be treated with the same relativistic light-quark action, allowing for nonperturbative renormalization using partial conservation of the vector current. We combine our results with experimental measurements of the differential decay rates to determine $|V_{cd}|^{D\toπ}=0.2238(11)^{\rm Expt}(15)^{\rm QCD}(04)^{\rm EW}(02)^{\rm SIB}[22]^{\rm QED}$ and $|V_{cs}|^{D\to K}=0.9589(23)^{\rm Expt}(40)^{\rm QCD}(15)^{\rm EW}(05)^{\rm SIB}[95]^{\rm QED}$ This result for $|V_{cd}|$ is the most precise to date, with a lattice-QCD error that is, for the first time for the semileptonic extraction, at the same level as the experimental error. Using recent measurements from BES III, we also give the first-ever determination of $|V_{cd}|^{D_s\to K}=0.258(15)^{\rm Expt}(01)^{\rm QCD}[03]^{\rm QED}$ from $D_s\to K \ellν$. Our results also furnish new Standard Model calculations of the lepton flavor universality ratios $R^{D\toπ}=0.98671(17)^{\rm QCD}[500]^{\rm QED}$, $R^{D\to K}=0.97606(16)^{\rm QCD}[500]^{\rm QED}$, and $R^{D_s\to K}=0.98099(10)^{\rm QCD}[500]^{\rm QED}$, which are consistent within $2σ$ with experimental measurements. Our extractions of $|V_{cd}|$ and $|V_{cs}|$, when combined with a value for $|V_{cb}|$, provide the most precise test of second-row CKM unitarity, finding agreement with unitarity at the level of one standard deviation.
