相对论重夸克格点量子色动力学的$Λ_b \to p \ell^- \barν_\ell$和$Λ_b \to Λ_c \ell^- \barν_\ell$形状因子
$Λ_b \to p \ell^- \barν_\ell$ and $Λ_b \to Λ_c \ell^- \barν_\ell$ form factors from lattice QCD with relativistic heavy quarks
William Detmold, Christoph Lehner, Stefan Meinel
备注：
40 pages, 15 figures, form factor parameters included as ancillary files. v3: new definitions of z-expansion parameters t_+ and other minor improvements
Measurements of the $Λ_b \to p \ell^- \barν_\ell$ and $Λ_b \to Λ_c \ell^- \barν_\ell$ decay rates can be used to determine the magnitudes of the CKM matrix elements $V_{ub}$ and $V_{cb}$, provided that the relevant hadronic form factors are known. Here we present a precise calculation of these form factors using lattice QCD with 2+1 flavors of dynamical domain-wall fermions. The $b$ and $c$ quarks are implemented with relativistic heavy-quark actions, allowing us to work directly at the physical heavy-quark masses. The lattice computation is performed for six different pion masses and two different lattice spacings, using gauge-field configurations generated by the RBC and UKQCD collaborations. The $b \to u$ and $b \to c$ currents are renormalized with a mostly nonperturbative method. We extrapolate the form factor results to the physical pion mass and the continuum limit, parametrizing the $q^2$-dependence using $z$-expansions. The form factors are presented in such a way as to enable the correlated propagation of both statistical and systematic uncertainties into derived quantities such as differential decay rates and asymmetries. Using these form factors, we present predictions for the $Λ_b \to p \ell^- \barν_\ell$ and $Λ_b \to Λ_c \ell^- \barν_\ell$ differential and integrated decay rates. Combined with experimental data, our results enable determinations of $|V_{ub}|$, $|V_{cb}|$, and $|V_{ub}/V_{cb}|$ with theory uncertainties of 4.4%, 2.2%, and 4.9%, respectively.
Evidence for the existence of $u d \bar{b} \bar{b}$ and the non-existence of $s s \bar{b} \bar{b}$ and $c c \bar{b} \bar{b}$ tetraquarks from lattice QCD
The search for new physics in $B \to K \ell^+\ell^-$ and $B \to K ν\barν$ using precise lattice QCD form factors
我们提出了HPQCD的改进的标量，矢量和张量形状因子的$B \to K$半轻子衰变，使用重HISQ形式主义更准确的归一化的弱电流。工作质量接近物理$b$上最好的合奏，包括三个合奏与物理轻夸克，我们涵盖了整个物理$q^2$范围内具有良好的精度。我们在$q^2=0$中的不确定性比以前的工作好三倍。我们比较标准模型的观测值，使用我们的形状因子的实验测量罕见的味道改变中性电流过程$B \to K \ell^+\ell^-$和$B \to K ν\barν$，并讨论出现的紧张局势的意义。
Inclusive semileptonic $D_s\to X_s\ell\barν$ decays from lattice QCD: continuum and chiral extrapolation
High Energy Accelerator Research Organization (KEK)（高能加速器研究机构）；PRISMA++ Cluster of Excellence & Institut für Kernphysik, Johannes-Gutenberg-Universität Mainz（美因茨约翰内斯·古腾堡大学 PRISMA++ 卓越集群与核物理研究所）；School of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学院）；STAG Research Center, University of Southampton（南安普顿大学 STAG 研究中心）；School of High Energy Accelerator Science, SOKENDAI (The Graduate University for Advanced Studies)（高级研究院（SOKENDAI）高能加速器科学学校）；RIKEN Center for Computational Science (R-CCS)（理化学研究所计算科学中心）；CERN, Theoretical Physics Department（欧洲核子研究中心理论物理部）
Rare kaon decays $K^- \to \ell^- \barν_\ell \ell'^{+} \ell'^{-}$: Standard Model predictions from lattice QCD
Dipartimento di Matematica e Fisica, Università Roma Tre（罗马第三大学数学与物理系）；INFN, Sezione di Roma Tre（意大利国家核物理研究所罗马三分部）；Dipartimento di Fisica and INFN, Università di Roma “Tor Vergata”（罗马托维加塔大学物理系及意大利国家核物理研究所）；Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre（意大利国家核物理研究所罗马三分部）；Physics Department and INFN Sezione di Roma La Sapienza（罗马第一大学物理系及意大利国家核物理研究所罗马分部）；Department of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学系）
Theoretical framework for lattice QCD computations of $B\to K \ell^+ \ell^-$ and $\bar{B}_s\to \ell^+\ell^- γ$ decays rates, including contributions from charming penguin diagrams
Università di Roma “Tor Vergata”（罗马托尔维加塔大学）；INFN, Sezione di Roma Tre（意大利国家核物理研究所罗马三分所）；INFN, Sezione di Roma（意大利国家核物理研究所罗马分所）；Università di Roma La Sapienza（罗马第一大学）；University of Southampton（南安普顿大学）
