Anticipating the important role of tree level FCNC processes in the indirect search for new physics at distance scales as short as 10^-19-10^-21 m, we present complete NLO QCD corrections to tree level Delta F=2 processes mediated by heavy colourless gauge bosons and scalars. Such contributions can be present at the fundamental level when GIM mechanism is absent as in numerous Z' models, gauged flavour models with new heavy neutral gauge bosons and Left-Right symmetric models with heavy neutral scalars. They can also be generated at one loop in models having GIM at the fundamental level and MFV of which Two-Higgs Doublet models with and without SUSY are the best known examples. In models containing vectorial heavy fermions that mix with the standard chiral quarks and models in which Z and SM neutral Higgs H mix with new heavy gauge bosons and scalars also tree-level Z and SM neutral Higgs contributions to Delta F=2 processes are possible. In all these extensions new local operators are generated having Wilson coefficients that are generally much stronger affected by RG QCD effects than it is the case of the SM operators. The new aspect of our work is the calculation of O(alpha_s) corrections to matching conditions for the Wilson coefficients of the contributing operators in the NDR-MS scheme that can be used in all models listed above. This allows to reduce certain unphysical scale and renormalization scheme dependences in the existing NLO calculations. We show explicitly how our results can be combined with the analytic formulae for the P_i^a QCD factors that include both hadronic matrix elements of contributing operators and RG evolution from high energy to low energy scales. For the masses of heavy gauge bosons and scalars O(1)TeV the remaining unphysical scale dependences for the mixing amplitudes are reduced typically from 10-25%, depending on the operator considered, down to 1-2%.
Next-to-leading order QCD corrections to the top quark associated with $γ$ production via model-independent flavor-changing neutral-current couplings at hadron colliders
Chirally enhanced corrections to FCNC processes in the generic MSSM
Chirally enhanced supersymmetric QCD corrections to FCNC processes are investigated in the framework of the MSSM with generic sources of flavor violation. These corrections arise from flavor-changing self-energy diagrams and can be absorbed into a finite renormalization of the squark-quark-gluino vertex. In this way enhanced two-loop and even three-loop diagrams can be efficiently included into a leading-order (LO) calculation. Our corrections substantially change the values of the parameters delta^{d,LL}_{23}, delta^{d,LR}_{23}, delta^{d,RL}_{23}, and delta^{d,RR}_{23} extracted from Br[B->X_…
Left-handed Z' and Z FCNC quark couplings facing new b -> s mu^+ mu^- data
鉴于最近关于B_{s,d}-> mu ^+ mu ^-和B_d-> K ^* mu ^+ mu ^-的改进的数据，我们重新审视两个简单的NP方案，其中b-> s mu ^+ mu ^-跃迁中的新FCNC电流完全由中性重规范玻色子Z '介导，具有纯LH复合耦合Δ_L ^{qb}（Z'）（q = d，s）以及与μ子的耦合Δ_A ^{mu mu}（Z '）和Δ_V ^{mu mu}（Z'）或SM Z玻色子与LH复合耦合Δ_L ^{qb}（Z）。我们演示了如何通过未来的Delta F = 2和b-> s mu ^+ mu ^-可观测量来确定这些耦合。各种可观测量之间的相关性可以测试这些NP场景。我们把结果作为Δ M_q/Δ M_q ^SM，S_{psi phi}和S_{psi K_S}的函数给出，这三个函数在这十年内应该得到精确的测定。我们计算在这些场景中BR（B_{s,d}-> mu ^+ mu ^-）和Delta M_{s,d}之间CMFV关系的违反。我们发现CMS和LHCb的B_{s,d}-> mu ^+ mu ^-的数据在两种情况下都可以重现，但在Z的情况下，Delta M_s和S_{psi phi}必须非常接近它们的SM值。对于B_d-> K ^* μ ^+ μ ^-反常，Z '方案可以显著地软化这些反常，而Z玻色子由于与μ子的小矢量耦合而失效。我们还指出，最近的建议，解释这些异…
NLO calculation of the Delta F = 2 Hamiltonians in the MSSM and phenomenological analysis of the B - Bbar mixing
我们给出了对MSSM强相互作用区中Delta F = 2哈密顿量Wilson系数的非线性光学修正，这是中性介子振荡的原因。这种修正，结合Delta F = 2算符的NLO异常维度矩阵和在晶格上计算的相应强子矩阵元，首次允许对与介子振荡相关的可观测量进行完整的NLO唯象分析。我们提出了在B_d - B_d棒扇区中的初步结果.
Next-to-leading order QCD corrections to the single top quark production via model-independent t-q-g flavor-changing neutral-current couplings at hadron colliders
Z-Z' Mixing and Z-Mediated FCNCs in SU(3)_C x SU(3)_L x U(1)_X Models
在规范群SU（3）_C x SU（3）_L x U（1）_X的基础上，现有的对331模型中FCNC过程的分析大多只考虑了一种新的重中性规范玻色子Z '的三能级交换。然而，由于Z-Z'混合，Z玻色子的相应贡献也存在，通常被忽略。我们计算了这些贡献对Delta F=2过程和稀有K，B_s和B_d衰变的影响，其中参数β的不同值区分了不同的331模型和SU（3）_L群下不同的费米子表示。我们找到了Z-Z'混合的一个一般表达式，它用beta，M_Z，M_Z'和tan（bar{beta}）表示，与2个Higgs Doublet模型相似，但与文献中所引用的不同。我们特别研究了beta=+-n/sqrt{3}（n= 1，2）的模型，这些模型是我们最近在关于B_{s,d} ->mu^+ mu^-和B_d->K^*（K）mu^+ mu^-的新数据的背景下研究的。我们发现，在Δ F=2跃迁和衰变的情况下，如B_d->K^*mu^+mu^-，这些新的贡献确实可以忽略不计，因为它们被带电轻子的小矢量Z耦合所抑制。然而，树能级Z交换对轴矢量耦合敏感的衰变的贡献，如B_{s,d} ->mu^+ mu^-和B_d->K mu^+ mu^-，以及中微子处于末态的衰变的贡献，如b->s nu bar{nu}跃迁，K^+->pi^+ nu bar{nu}和K_L-> pi ^0 nu bar{nu}，一般不能忽略，Z贡…
B-parameters of the complete set of matrix elements of (Delta B = 2) operators from the lattice
我们计算晶格上的“袋”参数的五个（Δ B = 2）运营商的超对称基础，通过结合它们的值确定在全QCD和静态限制HQET。从可及的重-轻介子质量到B介子质量的QCD结果的外推受到静态结果的限制。在MSbar（NDR）重整化方案中，HQET和QCD中相应结果的匹配首次在NLO精度下进行。所有结果都是在猝灭近似下得到的。
Constraints on flavor-changing neutral-current $Htq$ couplings from the signal of $tH$ associated production with QCD next-to-leading order accuracy at the LHC
The Anatomy of Z' and Z with Flavour Changing Neutral Currents in the Flavour Precision Era
SM的最简单的扩展通常会引入新的味源和CP破坏以及右手流，这就是在SM规范群中加入U（1）规范对称性。如果相应的重规范玻色子Z'介导的FCNC过程中的夸克部门在树级，这些新的物理贡献意味着一种模式的偏差，从SM的预期FCNC过程只取决于Z'耦合到费米子和它的质量。这意味着Δ F=2和Δ F=1观测值之间的严格相关性，这些观测值决定了Z '模型允许的参数空间的景观。预计风味精度时代（FPE）摆在我们面前，我们说明了这一点，通过搜索允许绿洲在这一景观假设显着较小的不确定性CKM和强子参数比目前可用。为此，我们分析了K^0-bar K^0和B^0_{s，d}-bar B^0_{s，d}系统中的Delta F=2观测值，以及罕见的K和B衰变，包括各种组合的左手和右手Z '-夸克耦合。我们确定了各种风味可观察值之间的一些相关性，这些风味可观察值可以测试和区分这些不同的Z'场景。强调了b->s l^+ l^-和b->s nu bar nu跃迁在这些研究中的重要作用。在M_Z '<3 TeV的条件下，在B_{s,d}和K介子系统中，由于施加了现有的味约束，出现了与SM期望值偏离的丰富模式.当M_Z '> 5 TeV时，在罕见的B_{s,d}衰变中发现Z'效应通常低于10%，甚至在FPE中也很难测量，而K->pi nu bar nu和K_L-> pi ^0 l^+ l^-衰变则提供了一个重要的入口…
$B_{(s)} \to S(a_0(1450), K_0^*(1430), f_0(1500))$ helicity form factors within QCD light-cone sum rules
Beihang University（北京航空航天大学）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；Chongqing University of Posts and Telecommunications（重庆邮电大学）；Chongqing University of Science and Technology（重庆科技大学）；Guizhou Minzu University（贵州民族大学）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）
